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mariadb/storage/maria/ma_pagecache.c
unknown 212313de55 Optimisation todo for loghandler added. 
Debug output information fixed.
Fixed direct page referencing in write mode.


storage/maria/ma_loghandler.c:
  TODO added.
storage/maria/ma_pagecache.c:
  Debug output information fixed.
  Fixed direct page referencing in write mode.
2007-10-07 23:27:03 +03:00

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/* Copyright (C) 2000-2006 MySQL AB
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
/*
These functions handle page cacheing for Maria tables.
One cache can handle many files.
It must contain buffers of the same blocksize.
init_pagecache() should be used to init cache handler.
The free list (free_block_list) is a stack like structure.
When a block is freed by free_block(), it is pushed onto the stack.
When a new block is required it is first tried to pop one from the stack.
If the stack is empty, it is tried to get a never-used block from the pool.
If this is empty too, then a block is taken from the LRU ring, flushing it
to disk, if necessary. This is handled in find_block().
With the new free list, the blocks can have three temperatures:
hot, warm and cold (which is free). This is remembered in the block header
by the enum PCBLOCK_TEMPERATURE temperature variable. Remembering the
temperature is necessary to correctly count the number of warm blocks,
which is required to decide when blocks are allowed to become hot. Whenever
a block is inserted to another (sub-)chain, we take the old and new
temperature into account to decide if we got one more or less warm block.
blocks_unused is the sum of never used blocks in the pool and of currently
free blocks. blocks_used is the number of blocks fetched from the pool and
as such gives the maximum number of in-use blocks at any time.
*/
#include "maria_def.h"
#include <m_string.h>
#include "ma_pagecache.h"
#include <my_bit.h>
#include <errno.h>
#include <stdarg.h>
/*
Some compilation flags have been added specifically for this module
to control the following:
- not to let a thread to yield the control when reading directly
from page cache, which might improve performance in many cases;
to enable this add:
#define SERIALIZED_READ_FROM_CACHE
- to set an upper bound for number of threads simultaneously
using the page cache; this setting helps to determine an optimal
size for hash table and improve performance when the number of
blocks in the page cache much less than the number of threads
accessing it;
to set this number equal to <N> add
#define MAX_THREADS <N>
- to substitute calls of pthread_cond_wait for calls of
pthread_cond_timedwait (wait with timeout set up);
this setting should be used only when you want to trap a deadlock
situation, which theoretically should not happen;
to set timeout equal to <T> seconds add
#define PAGECACHE_TIMEOUT <T>
- to enable the module traps and to send debug information from
page cache module to a special debug log add:
#define PAGECACHE_DEBUG
the name of this debug log file <LOG NAME> can be set through:
#define PAGECACHE_DEBUG_LOG <LOG NAME>
if the name is not defined, it's set by default;
if the PAGECACHE_DEBUG flag is not set up and we are in a debug
mode, i.e. when ! defined(DBUG_OFF), the debug information from the
module is sent to the regular debug log.
Example of the settings:
#define SERIALIZED_READ_FROM_CACHE
#define MAX_THREADS 100
#define PAGECACHE_TIMEOUT 1
#define PAGECACHE_DEBUG
#define PAGECACHE_DEBUG_LOG "my_pagecache_debug.log"
*/
/*
In key cache we have external raw locking here we use
SERIALIZED_READ_FROM_CACHE to avoid problem of reading
not consistent data from the page.
(keycache functions (key_cache_read(), key_cache_insert() and
key_cache_write()) rely on external MyISAM lock, we don't)
*/
#define SERIALIZED_READ_FROM_CACHE yes
#define PCBLOCK_INFO(B) \
DBUG_PRINT("info", \
("block: 0x%lx file: %lu page: %lu s: %0x hshL: 0x%lx req: %u/%u " \
"wrlocks: %u pins: %u", \
(ulong)(B), \
(ulong)((B)->hash_link ? \
(B)->hash_link->file.file : \
0), \
(ulong)((B)->hash_link ? \
(B)->hash_link->pageno : \
0), \
(B)->status, \
(ulong)(B)->hash_link, \
(uint) (B)->requests, \
(uint)((B)->hash_link ? \
(B)->hash_link->requests : \
0), \
block->wlocks, \
(uint)(B)->pins))
/* TODO: put it to my_static.c */
my_bool my_disable_flush_pagecache_blocks= 0;
/**
when flushing pages of a file, it can happen that we take some dirty blocks
out of changed_blocks[]; Checkpoint must not run at this moment.
*/
uint changed_blocks_is_incomplete= 0;
#define STRUCT_PTR(TYPE, MEMBER, a) \
(TYPE *) ((char *) (a) - offsetof(TYPE, MEMBER))
/* types of condition variables */
#define COND_FOR_REQUESTED 0 /* queue of thread waiting for read operation */
#define COND_FOR_SAVED 1 /* queue of thread waiting for flush */
#define COND_FOR_WRLOCK 2 /* queue of write lock */
#define COND_SIZE 3 /* number of COND_* queues */
/* offset of LSN on the page */
#define PAGE_LSN_OFFSET 0
typedef pthread_cond_t KEYCACHE_CONDVAR;
/* descriptor of the page in the page cache block buffer */
struct st_pagecache_page
{
PAGECACHE_FILE file; /* file to which the page belongs to */
pgcache_page_no_t pageno; /* number of the page in the file */
};
/* element in the chain of a hash table bucket */
struct st_pagecache_hash_link
{
struct st_pagecache_hash_link
*next, **prev; /* to connect links in the same bucket */
struct st_pagecache_block_link
*block; /* reference to the block for the page: */
PAGECACHE_FILE file; /* from such a file */
pgcache_page_no_t pageno; /* this page */
uint requests; /* number of requests for the page */
};
/* simple states of a block */
#define PCBLOCK_ERROR 1 /* an error occurred when performing disk i/o */
#define PCBLOCK_READ 2 /* the is page in the block buffer */
#define PCBLOCK_IN_SWITCH 4 /* block is preparing to read new page */
#define PCBLOCK_REASSIGNED 8 /* block does not accept requests for old page */
#define PCBLOCK_IN_FLUSH 16 /* block is in flush operation */
#define PCBLOCK_CHANGED 32 /* block buffer contains a dirty page */
/* page status, returned by find_block */
#define PAGE_READ 0
#define PAGE_TO_BE_READ 1
#define PAGE_WAIT_TO_BE_READ 2
/* block temperature determines in which (sub-)chain the block currently is */
enum PCBLOCK_TEMPERATURE { PCBLOCK_COLD /*free*/ , PCBLOCK_WARM , PCBLOCK_HOT };
/* debug info */
#ifndef DBUG_OFF
static const char *page_cache_page_type_str[]=
{
/* used only for control page type changing during debugging */
"EMPTY",
"PLAIN",
"LSN",
"READ_UNKNOWN"
};
static const char *page_cache_page_write_mode_str[]=
{
"DELAY",
"DONE"
};
static const char *page_cache_page_lock_str[]=
{
"free -> free",
"read -> read",
"write -> write",
"free -> read",
"free -> write",
"read -> free",
"write -> free",
"write -> read"
};
static const char *page_cache_page_pin_str[]=
{
"pinned -> pinned",
"unpinned -> unpinned",
"unpinned -> pinned",
"pinned -> unpinned"
};
typedef struct st_pagecache_pin_info
{
struct st_pagecache_pin_info *next, **prev;
struct st_my_thread_var *thread;
} PAGECACHE_PIN_INFO;
/*
st_pagecache_lock_info structure should be kept in next, prev, thread part
compatible with st_pagecache_pin_info to be compatible in functions.
*/
typedef struct st_pagecache_lock_info
{
struct st_pagecache_lock_info *next, **prev;
struct st_my_thread_var *thread;
my_bool write_lock;
} PAGECACHE_LOCK_INFO;
/* service functions maintain debugging info about pin & lock */
/*
Links information about thread pinned/locked the block to the list
SYNOPSIS
info_link()
list the list to link in
node the node which should be linked
*/
static void info_link(PAGECACHE_PIN_INFO **list, PAGECACHE_PIN_INFO *node)
{
if ((node->next= *list))
node->next->prev= &(node->next);
*list= node;
node->prev= list;
}
/*
Unlinks information about thread pinned/locked the block from the list
SYNOPSIS
info_unlink()
node the node which should be unlinked
*/
static void info_unlink(PAGECACHE_PIN_INFO *node)
{
if ((*node->prev= node->next))
node->next->prev= node->prev;
}
/*
Finds information about given thread in the list of threads which
pinned/locked this block.
SYNOPSIS
info_find()
list the list where to find the thread
thread thread ID (reference to the st_my_thread_var
of the thread)
RETURN
0 - the thread was not found
pointer to the information node of the thread in the list
*/
static PAGECACHE_PIN_INFO *info_find(PAGECACHE_PIN_INFO *list,
struct st_my_thread_var *thread)
{
register PAGECACHE_PIN_INFO *i= list;
for(; i != 0; i= i->next)
if (i->thread == thread)
return i;
return 0;
}
#endif /* !DBUG_OFF */
/* page cache block */
struct st_pagecache_block_link
{
struct st_pagecache_block_link
*next_used, **prev_used; /* to connect links in the LRU chain (ring) */
struct st_pagecache_block_link
*next_changed, **prev_changed; /* for lists of file dirty/clean blocks */
struct st_pagecache_hash_link
*hash_link; /* backward ptr to referring hash_link */
#ifndef DBUG_OFF
PAGECACHE_PIN_INFO *pin_list;
PAGECACHE_LOCK_INFO *lock_list;
#endif
KEYCACHE_CONDVAR *condvar; /* condition variable for 'no readers' event */
uchar *buffer; /* buffer for the block page */
PAGECACHE_FILE *write_locker;
ulonglong last_hit_time; /* timestamp of the last hit */
WQUEUE
wqueue[COND_SIZE]; /* queues on waiting requests for new/old pages */
uint requests; /* number of requests for the block */
uint status; /* state of the block */
uint pins; /* pin counter */
uint wlocks; /* write locks counter */
enum PCBLOCK_TEMPERATURE temperature; /* block temperature: cold, warm, hot */
enum pagecache_page_type type; /* type of the block */
uint hits_left; /* number of hits left until promotion */
/** @brief LSN when first became dirty; LSN_MAX means "not yet set" */
LSN rec_lsn;
};
#ifndef DBUG_OFF
/* debug checks */
#ifdef NOT_USED
static my_bool info_check_pin(PAGECACHE_BLOCK_LINK *block,
enum pagecache_page_pin mode
__attribute__((unused)))
{
struct st_my_thread_var *thread= my_thread_var;
PAGECACHE_PIN_INFO *info= info_find(block->pin_list, thread);
DBUG_ENTER("info_check_pin");
DBUG_PRINT("enter", ("thread: 0x%lx pin: %s",
(ulong) thread, page_cache_page_pin_str[mode]));
if (info)
{
if (mode == PAGECACHE_PIN_LEFT_UNPINNED)
{
DBUG_PRINT("info",
("info_check_pin: thread: 0x%lx block: 0x%lx ; LEFT_UNPINNED!!!",
(ulong)thread, (ulong)block));
DBUG_RETURN(1);
}
else if (mode == PAGECACHE_PIN)
{
DBUG_PRINT("info",
("info_check_pin: thread: 0x%lx block: 0x%lx ; PIN!!!",
(ulong)thread, (ulong)block));
DBUG_RETURN(1);
}
}
else
{
if (mode == PAGECACHE_PIN_LEFT_PINNED)
{
DBUG_PRINT("info",
("info_check_pin: thread: 0x%lx block: 0x%lx ; LEFT_PINNED!!!",
(ulong)thread, (ulong)block));
DBUG_RETURN(1);
}
else if (mode == PAGECACHE_UNPIN)
{
DBUG_PRINT("info",
("info_check_pin: thread: 0x%lx block: 0x%lx ; UNPIN!!!",
(ulong)thread, (ulong)block));
DBUG_RETURN(1);
}
}
DBUG_RETURN(0);
}
/*
Debug function which checks current lock/pin state and requested changes
SYNOPSIS
info_check_lock()
lock requested lock changes
pin requested pin changes
RETURN
0 - OK
1 - Error
*/
static my_bool info_check_lock(PAGECACHE_BLOCK_LINK *block,
enum pagecache_page_lock lock,
enum pagecache_page_pin pin)
{
struct st_my_thread_var *thread= my_thread_var;
PAGECACHE_LOCK_INFO *info=
(PAGECACHE_LOCK_INFO *) info_find((PAGECACHE_PIN_INFO *) block->lock_list,
thread);
DBUG_ENTER("info_check_lock");
switch(lock)
{
case PAGECACHE_LOCK_LEFT_UNLOCKED:
if (pin != PAGECACHE_PIN_LEFT_UNPINNED ||
info)
goto error;
break;
case PAGECACHE_LOCK_LEFT_READLOCKED:
if ((pin != PAGECACHE_PIN_LEFT_UNPINNED &&
pin != PAGECACHE_PIN_LEFT_PINNED) ||
info == 0 || info->write_lock)
goto error;
break;
case PAGECACHE_LOCK_LEFT_WRITELOCKED:
if (pin != PAGECACHE_PIN_LEFT_PINNED ||
info == 0 || !info->write_lock)
goto error;
break;
case PAGECACHE_LOCK_READ:
if ((pin != PAGECACHE_PIN_LEFT_UNPINNED &&
pin != PAGECACHE_PIN) ||
info != 0)
goto error;
break;
case PAGECACHE_LOCK_WRITE:
if (pin != PAGECACHE_PIN ||
info != 0)
goto error;
break;
case PAGECACHE_LOCK_READ_UNLOCK:
if ((pin != PAGECACHE_PIN_LEFT_UNPINNED &&
pin != PAGECACHE_UNPIN) ||
info == 0 || info->write_lock)
goto error;
break;
case PAGECACHE_LOCK_WRITE_UNLOCK:
if (pin != PAGECACHE_UNPIN ||
info == 0 || !info->write_lock)
goto error;
break;
case PAGECACHE_LOCK_WRITE_TO_READ:
if ((pin != PAGECACHE_PIN_LEFT_PINNED &&
pin != PAGECACHE_UNPIN) ||
info == 0 || !info->write_lock)
goto error;
break;
}
DBUG_RETURN(0);
error:
DBUG_PRINT("info",
("info_check_lock: thread: 0x%lx block 0x%lx: info: %d wrt: %d,"
"to lock: %s, to pin: %s",
(ulong)thread, (ulong)block, test(info),
(info ? info->write_lock : 0),
page_cache_page_lock_str[lock],
page_cache_page_pin_str[pin]));
DBUG_RETURN(1);
}
#endif /* NOT_USED */
#endif /* !DBUG_OFF */
#define FLUSH_CACHE 2000 /* sort this many blocks at once */
static void free_block(PAGECACHE *pagecache, PAGECACHE_BLOCK_LINK *block);
#ifndef DBUG_OFF
static void test_key_cache(PAGECACHE *pagecache,
const char *where, my_bool lock);
#endif
#define PAGECACHE_HASH(p, f, pos) (((ulong) (pos) + \
(ulong) (f).file) & (p->hash_entries-1))
#define FILE_HASH(f) ((uint) (f).file & (PAGECACHE_CHANGED_BLOCKS_HASH - 1))
#define DEFAULT_PAGECACHE_DEBUG_LOG "pagecache_debug.log"
#if defined(PAGECACHE_DEBUG) && ! defined(PAGECACHE_DEBUG_LOG)
#define PAGECACHE_DEBUG_LOG DEFAULT_PAGECACHE_DEBUG_LOG
#endif
#if defined(PAGECACHE_DEBUG_LOG)
static FILE *pagecache_debug_log= NULL;
static void pagecache_debug_print _VARARGS((const char *fmt, ...));
#define PAGECACHE_DEBUG_OPEN \
if (!pagecache_debug_log) \
{ \
pagecache_debug_log= fopen(PAGECACHE_DEBUG_LOG, "w"); \
(void) setvbuf(pagecache_debug_log, NULL, _IOLBF, BUFSIZ); \
}
#define PAGECACHE_DEBUG_CLOSE \
if (pagecache_debug_log) \
{ \
fclose(pagecache_debug_log); \
pagecache_debug_log= 0; \
}
#else
#define PAGECACHE_DEBUG_OPEN
#define PAGECACHE_DEBUG_CLOSE
#endif /* defined(PAGECACHE_DEBUG_LOG) */
#if defined(PAGECACHE_DEBUG_LOG) && defined(PAGECACHE_DEBUG)
#define KEYCACHE_DBUG_PRINT(l, m) \
{ if (pagecache_debug_log) \
fprintf(pagecache_debug_log, "%s: ", l); \
pagecache_debug_print m; }
#define KEYCACHE_DBUG_ASSERT(a) \
{ if (! (a) && pagecache_debug_log) \
fclose(pagecache_debug_log); \
assert(a); }
#else
#define KEYCACHE_DBUG_PRINT(l, m) DBUG_PRINT(l, m)
#define KEYCACHE_DBUG_ASSERT(a) DBUG_ASSERT(a)
#endif /* defined(PAGECACHE_DEBUG_LOG) && defined(PAGECACHE_DEBUG) */
#if defined(PAGECACHE_DEBUG) || !defined(DBUG_OFF)
#ifdef THREAD
static long pagecache_thread_id;
#define KEYCACHE_THREAD_TRACE(l) \
KEYCACHE_DBUG_PRINT(l,("|thread %ld",pagecache_thread_id))
#define KEYCACHE_THREAD_TRACE_BEGIN(l) \
{ struct st_my_thread_var *thread_var= my_thread_var; \
pagecache_thread_id= thread_var->id; \
KEYCACHE_DBUG_PRINT(l,("[thread %ld",pagecache_thread_id)) }
#define KEYCACHE_THREAD_TRACE_END(l) \
KEYCACHE_DBUG_PRINT(l,("]thread %ld",pagecache_thread_id))
#else /* THREAD */
#define KEYCACHE_THREAD_TRACE(l) KEYCACHE_DBUG_PRINT(l,(""))
#define KEYCACHE_THREAD_TRACE_BEGIN(l) KEYCACHE_DBUG_PRINT(l,(""))
#define KEYCACHE_THREAD_TRACE_END(l) KEYCACHE_DBUG_PRINT(l,(""))
#endif /* THREAD */
#else
#define KEYCACHE_THREAD_TRACE_BEGIN(l)
#define KEYCACHE_THREAD_TRACE_END(l)
#define KEYCACHE_THREAD_TRACE(l)
#endif /* defined(PAGECACHE_DEBUG) || !defined(DBUG_OFF) */
#define PCBLOCK_NUMBER(p, b) \
((uint) (((char*)(b)-(char *) p->block_root)/sizeof(PAGECACHE_BLOCK_LINK)))
#define PAGECACHE_HASH_LINK_NUMBER(p, h) \
((uint) (((char*)(h)-(char *) p->hash_link_root)/ \
sizeof(PAGECACHE_HASH_LINK)))
#if (defined(PAGECACHE_TIMEOUT) && !defined(__WIN__)) || defined(PAGECACHE_DEBUG)
static int pagecache_pthread_cond_wait(pthread_cond_t *cond,
pthread_mutex_t *mutex);
#else
#define pagecache_pthread_cond_wait pthread_cond_wait
#endif
#if defined(PAGECACHE_DEBUG)
static int ___pagecache_pthread_mutex_lock(pthread_mutex_t *mutex);
static void ___pagecache_pthread_mutex_unlock(pthread_mutex_t *mutex);
static int ___pagecache_pthread_cond_signal(pthread_cond_t *cond);
#define pagecache_pthread_mutex_lock(M) \
{ DBUG_PRINT("lock", ("mutex lock 0x%lx %u", (ulong)(M), __LINE__)); \
___pagecache_pthread_mutex_lock(M);}
#define pagecache_pthread_mutex_unlock(M) \
{ DBUG_PRINT("lock", ("mutex unlock 0x%lx %u", (ulong)(M), __LINE__)); \
___pagecache_pthread_mutex_unlock(M);}
#define pagecache_pthread_cond_signal(M) \
{ DBUG_PRINT("lock", ("signal 0x%lx %u", (ulong)(M), __LINE__)); \
___pagecache_pthread_cond_signal(M);}
#else
#define pagecache_pthread_mutex_lock pthread_mutex_lock
#define pagecache_pthread_mutex_unlock pthread_mutex_unlock
#define pagecache_pthread_cond_signal pthread_cond_signal
#endif /* defined(PAGECACHE_DEBUG) */
extern my_bool translog_flush(LSN lsn);
/*
Write page to the disk
SYNOPSIS
pagecache_fwrite()
pagecache - page cache pointer
filedesc - pagecache file descriptor structure
buffer - buffer which we will write
type - page type (plain or with LSN)
flags - MYF() flags
RETURN
0 - OK
!=0 - Error
*/
static uint pagecache_fwrite(PAGECACHE *pagecache,
PAGECACHE_FILE *filedesc,
uchar *buffer,
pgcache_page_no_t pageno,
enum pagecache_page_type type,
myf flags)
{
DBUG_ENTER("pagecache_fwrite");
DBUG_ASSERT(type != PAGECACHE_READ_UNKNOWN_PAGE);
if (type == PAGECACHE_LSN_PAGE)
{
LSN lsn;
DBUG_PRINT("info", ("Log handler call"));
/* TODO: integrate with page format */
lsn= lsn_korr(buffer + PAGE_LSN_OFFSET);
DBUG_ASSERT(LSN_VALID(lsn));
translog_flush(lsn);
}
DBUG_RETURN(my_pwrite(filedesc->file, buffer, pagecache->block_size,
(pageno)<<(pagecache->shift), flags));
}
/*
Read page from the disk
SYNOPSIS
pagecache_fread()
pagecache - page cache pointer
filedesc - pagecache file descriptor structure
buffer - buffer in which we will read
pageno - page number
flags - MYF() flags
*/
#define pagecache_fread(pagecache, filedesc, buffer, pageno, flags) \
my_pread((filedesc)->file, buffer, pagecache->block_size, \
(pageno)<<(pagecache->shift), flags)
/*
next_power(value) is 2 at the power of (1+floor(log2(value)));
e.g. next_power(2)=4, next_power(3)=4.
*/
static inline uint next_power(uint value)
{
return (uint) my_round_up_to_next_power((uint32) value) << 1;
}
/*
Initialize a page cache
SYNOPSIS
init_pagecache()
pagecache pointer to a page cache data structure
key_cache_block_size size of blocks to keep cached data
use_mem total memory to use for the key cache
division_limit division limit (may be zero)
age_threshold age threshold (may be zero)
block_size size of block (should be power of 2)
RETURN VALUE
number of blocks in the key cache, if successful,
0 - otherwise.
NOTES.
if pagecache->inited != 0 we assume that the key cache
is already initialized. This is for now used by myisamchk, but shouldn't
be something that a program should rely on!
It's assumed that no two threads call this function simultaneously
referring to the same key cache handle.
*/
ulong init_pagecache(PAGECACHE *pagecache, size_t use_mem,
uint division_limit, uint age_threshold,
uint block_size)
{
ulong blocks, hash_links, length;
int error;
DBUG_ENTER("init_pagecache");
DBUG_ASSERT(block_size >= 512);
PAGECACHE_DEBUG_OPEN;
if (pagecache->inited && pagecache->disk_blocks > 0)
{
DBUG_PRINT("warning",("key cache already in use"));
DBUG_RETURN(0);
}
pagecache->global_cache_w_requests= pagecache->global_cache_r_requests= 0;
pagecache->global_cache_read= pagecache->global_cache_write= 0;
pagecache->disk_blocks= -1;
if (! pagecache->inited)
{
pagecache->inited= 1;
pagecache->in_init= 0;
pthread_mutex_init(&pagecache->cache_lock, MY_MUTEX_INIT_FAST);
pagecache->resize_queue.last_thread= NULL;
}
pagecache->mem_size= use_mem;
pagecache->block_size= block_size;
pagecache->shift= my_bit_log2(block_size);
DBUG_PRINT("info", ("block_size: %u",
block_size));
DBUG_ASSERT(((uint)(1 << pagecache->shift)) == block_size);
blocks= (ulong) (use_mem / (sizeof(PAGECACHE_BLOCK_LINK) +
2 * sizeof(PAGECACHE_HASH_LINK) +
sizeof(PAGECACHE_HASH_LINK*) *
5/4 + block_size));
/*
We need to support page cache with just one block to be able to do
scanning of rows-in-block files
*/
if (blocks >= 1)
{
for ( ; ; )
{
/* Set my_hash_entries to the next bigger 2 power */
if ((pagecache->hash_entries= next_power(blocks)) <
(blocks) * 5/4)
pagecache->hash_entries<<= 1;
hash_links= 2 * blocks;
#if defined(MAX_THREADS)
if (hash_links < MAX_THREADS + blocks - 1)
hash_links= MAX_THREADS + blocks - 1;
#endif
while ((length= (ALIGN_SIZE(blocks * sizeof(PAGECACHE_BLOCK_LINK)) +
ALIGN_SIZE(hash_links * sizeof(PAGECACHE_HASH_LINK)) +
ALIGN_SIZE(sizeof(PAGECACHE_HASH_LINK*) *
pagecache->hash_entries))) +
(blocks << pagecache->shift) > use_mem)
blocks--;
/* Allocate memory for cache page buffers */
if ((pagecache->block_mem=
my_large_malloc((ulong) blocks * pagecache->block_size,
MYF(MY_WME))))
{
/*
Allocate memory for blocks, hash_links and hash entries;
For each block 2 hash links are allocated
*/
if ((pagecache->block_root=
(PAGECACHE_BLOCK_LINK*) my_malloc((size_t) length, MYF(0))))
break;
my_large_free(pagecache->block_mem, MYF(0));
pagecache->block_mem= 0;
}
if (blocks < 8)
{
my_errno= ENOMEM;
goto err;
}
blocks= blocks / 4*3;
}
pagecache->blocks_unused= blocks;
pagecache->disk_blocks= (long) blocks;
pagecache->hash_links= hash_links;
pagecache->hash_root=
(PAGECACHE_HASH_LINK**) ((char*) pagecache->block_root +
ALIGN_SIZE(blocks*sizeof(PAGECACHE_BLOCK_LINK)));
pagecache->hash_link_root=
(PAGECACHE_HASH_LINK*) ((char*) pagecache->hash_root +
ALIGN_SIZE((sizeof(PAGECACHE_HASH_LINK*) *
pagecache->hash_entries)));
bzero((uchar*) pagecache->block_root,
pagecache->disk_blocks * sizeof(PAGECACHE_BLOCK_LINK));
bzero((uchar*) pagecache->hash_root,
pagecache->hash_entries * sizeof(PAGECACHE_HASH_LINK*));
bzero((uchar*) pagecache->hash_link_root,
pagecache->hash_links * sizeof(PAGECACHE_HASH_LINK));
pagecache->hash_links_used= 0;
pagecache->free_hash_list= NULL;
pagecache->blocks_used= pagecache->blocks_changed= 0;
pagecache->global_blocks_changed= 0;
pagecache->blocks_available=0; /* For debugging */
/* The LRU chain is empty after initialization */
pagecache->used_last= NULL;
pagecache->used_ins= NULL;
pagecache->free_block_list= NULL;
pagecache->time= 0;
pagecache->warm_blocks= 0;
pagecache->min_warm_blocks= (division_limit ?
blocks * division_limit / 100 + 1 :
blocks);
pagecache->age_threshold= (age_threshold ?
blocks * age_threshold / 100 :
blocks);
pagecache->cnt_for_resize_op= 0;
pagecache->resize_in_flush= 0;
pagecache->can_be_used= 1;
pagecache->waiting_for_hash_link.last_thread= NULL;
pagecache->waiting_for_block.last_thread= NULL;
DBUG_PRINT("exit",
("disk_blocks: %ld block_root: 0x%lx hash_entries: %ld\
hash_root: 0x%lx hash_links: %ld hash_link_root: 0x%lx",
pagecache->disk_blocks, (long) pagecache->block_root,
pagecache->hash_entries, (long) pagecache->hash_root,
pagecache->hash_links, (long) pagecache->hash_link_root));
bzero((uchar*) pagecache->changed_blocks,
sizeof(pagecache->changed_blocks[0]) *
PAGECACHE_CHANGED_BLOCKS_HASH);
bzero((uchar*) pagecache->file_blocks,
sizeof(pagecache->file_blocks[0]) *
PAGECACHE_CHANGED_BLOCKS_HASH);
}
pagecache->blocks= pagecache->disk_blocks > 0 ? pagecache->disk_blocks : 0;
DBUG_RETURN((ulong) pagecache->disk_blocks);
err:
error= my_errno;
pagecache->disk_blocks= 0;
pagecache->blocks= 0;
if (pagecache->block_mem)
{
my_large_free((uchar*) pagecache->block_mem, MYF(0));
pagecache->block_mem= NULL;
}
if (pagecache->block_root)
{
my_free((uchar*) pagecache->block_root, MYF(0));
pagecache->block_root= NULL;
}
my_errno= error;
pagecache->can_be_used= 0;
DBUG_RETURN(0);
}
/*
Flush all blocks in the key cache to disk
*/
#ifdef NOT_USED
static int flush_all_key_blocks(PAGECACHE *pagecache)
{
#if defined(PAGECACHE_DEBUG)
uint cnt=0;
#endif
while (pagecache->blocks_changed > 0)
{
PAGECACHE_BLOCK_LINK *block;
for (block= pagecache->used_last->next_used ; ; block=block->next_used)
{
if (block->hash_link)
{
#if defined(PAGECACHE_DEBUG)
cnt++;
KEYCACHE_DBUG_ASSERT(cnt <= pagecache->blocks_used);
#endif
if (flush_pagecache_blocks_int(pagecache, &block->hash_link->file,
FLUSH_RELEASE))
return 1;
break;
}
if (block == pagecache->used_last)
break;
}
}
return 0;
}
#endif /* NOT_USED */
/*
Resize a key cache
SYNOPSIS
resize_pagecache()
pagecache pointer to a page cache data structure
use_mem total memory to use for the new key cache
division_limit new division limit (if not zero)
age_threshold new age threshold (if not zero)
RETURN VALUE
number of blocks in the key cache, if successful,
0 - otherwise.
NOTES.
The function first compares the memory size parameter
with the key cache value.
If they differ the function free the the memory allocated for the
old key cache blocks by calling the end_pagecache function and
then rebuilds the key cache with new blocks by calling
init_key_cache.
The function starts the operation only when all other threads
performing operations with the key cache let her to proceed
(when cnt_for_resize=0).
Before being usable, this function needs:
- to receive fixes for BUG#17332 "changing key_buffer_size on a running
server can crash under load" similar to those done to the key cache
- to have us (Sanja) look at the additional constraints placed on
resizing, due to the page locking specific to this page cache.
So we disable it for now.
*/
#if NOT_USED /* keep disabled until code is fixed see above !! */
ulong resize_pagecache(PAGECACHE *pagecache,
size_t use_mem, uint division_limit,
uint age_threshold)
{
ulong blocks;
#ifdef THREAD
struct st_my_thread_var *thread;
WQUEUE *wqueue;
#endif
DBUG_ENTER("resize_pagecache");
if (!pagecache->inited)
DBUG_RETURN(pagecache->disk_blocks);
if(use_mem == pagecache->mem_size)
{
change_pagecache_param(pagecache, division_limit, age_threshold);
DBUG_RETURN(pagecache->disk_blocks);
}
pagecache_pthread_mutex_lock(&pagecache->cache_lock);
#ifdef THREAD
wqueue= &pagecache->resize_queue;
thread= my_thread_var;
wqueue_link_into_queue(wqueue, thread);
while (wqueue->last_thread->next != thread)
{
pagecache_pthread_cond_wait(&thread->suspend, &pagecache->cache_lock);
}
#endif
pagecache->resize_in_flush= 1;
if (flush_all_key_blocks(pagecache))
{
/* TODO: if this happens, we should write a warning in the log file ! */
pagecache->resize_in_flush= 0;
blocks= 0;
pagecache->can_be_used= 0;
goto finish;
}
pagecache->resize_in_flush= 0;
pagecache->can_be_used= 0;
#ifdef THREAD
while (pagecache->cnt_for_resize_op)
{
KEYCACHE_DBUG_PRINT("resize_pagecache: wait",
("suspend thread %ld", thread->id));
pagecache_pthread_cond_wait(&thread->suspend, &pagecache->cache_lock);
}
#else
KEYCACHE_DBUG_ASSERT(pagecache->cnt_for_resize_op == 0);
#endif
end_pagecache(pagecache, 0); /* Don't free mutex */
/* The following will work even if use_mem is 0 */
blocks= init_pagecache(pagecache, pagecache->block_size, use_mem,
division_limit, age_threshold);
finish:
#ifdef THREAD
wqueue_unlink_from_queue(wqueue, thread);
/* Signal for the next resize request to proceeed if any */
if (wqueue->last_thread)
{
KEYCACHE_DBUG_PRINT("resize_pagecache: signal",
("thread %ld", wqueue->last_thread->next->id));
pagecache_pthread_cond_signal(&wqueue->last_thread->next->suspend);
}
#endif
pagecache_pthread_mutex_unlock(&pagecache->cache_lock);
DBUG_RETURN(blocks);
}
#endif /* 0 */
/*
Increment counter blocking resize key cache operation
*/
static inline void inc_counter_for_resize_op(PAGECACHE *pagecache)
{
pagecache->cnt_for_resize_op++;
}
/*
Decrement counter blocking resize key cache operation;
Signal the operation to proceed when counter becomes equal zero
*/
static inline void dec_counter_for_resize_op(PAGECACHE *pagecache)
{
#ifdef THREAD
struct st_my_thread_var *last_thread;
if (!--pagecache->cnt_for_resize_op &&
(last_thread= pagecache->resize_queue.last_thread))
{
KEYCACHE_DBUG_PRINT("dec_counter_for_resize_op: signal",
("thread %ld", last_thread->next->id));
pagecache_pthread_cond_signal(&last_thread->next->suspend);
}
#else
pagecache->cnt_for_resize_op--;
#endif
}
/*
Change the page cache parameters
SYNOPSIS
change_pagecache_param()
pagecache pointer to a page cache data structure
division_limit new division limit (if not zero)
age_threshold new age threshold (if not zero)
RETURN VALUE
none
NOTES.
Presently the function resets the key cache parameters
concerning midpoint insertion strategy - division_limit and
age_threshold.
*/
void change_pagecache_param(PAGECACHE *pagecache, uint division_limit,
uint age_threshold)
{
DBUG_ENTER("change_pagecache_param");
pagecache_pthread_mutex_lock(&pagecache->cache_lock);
if (division_limit)
pagecache->min_warm_blocks= (pagecache->disk_blocks *
division_limit / 100 + 1);
if (age_threshold)
pagecache->age_threshold= (pagecache->disk_blocks *
age_threshold / 100);
pagecache_pthread_mutex_unlock(&pagecache->cache_lock);
DBUG_VOID_RETURN;
}
/*
Removes page cache from memory. Does NOT flush pages to disk.
SYNOPSIS
end_pagecache()
pagecache page cache handle
cleanup Complete free (Free also mutex for key cache)
RETURN VALUE
none
*/
void end_pagecache(PAGECACHE *pagecache, my_bool cleanup)
{
DBUG_ENTER("end_pagecache");
DBUG_PRINT("enter", ("key_cache: 0x%lx", (long) pagecache));
if (!pagecache->inited)
DBUG_VOID_RETURN;
if (pagecache->disk_blocks > 0)
{
if (pagecache->block_mem)
{
my_large_free((uchar*) pagecache->block_mem, MYF(0));
pagecache->block_mem= NULL;
my_free((uchar*) pagecache->block_root, MYF(0));
pagecache->block_root= NULL;
}
pagecache->disk_blocks= -1;
/* Reset blocks_changed to be safe if flush_all_key_blocks is called */
pagecache->blocks_changed= 0;
}
DBUG_PRINT("status", ("used: %lu changed: %lu w_requests: %lu "
"writes: %lu r_requests: %lu reads: %lu",
pagecache->blocks_used, pagecache->global_blocks_changed,
(ulong) pagecache->global_cache_w_requests,
(ulong) pagecache->global_cache_write,
(ulong) pagecache->global_cache_r_requests,
(ulong) pagecache->global_cache_read));
if (cleanup)
{
pthread_mutex_destroy(&pagecache->cache_lock);
pagecache->inited= pagecache->can_be_used= 0;
PAGECACHE_DEBUG_CLOSE;
}
DBUG_VOID_RETURN;
} /* end_pagecache */
/*
Unlink a block from the chain of dirty/clean blocks
*/
static inline void unlink_changed(PAGECACHE_BLOCK_LINK *block)
{
if (block->next_changed)
block->next_changed->prev_changed= block->prev_changed;
*block->prev_changed= block->next_changed;
}
/*
Link a block into the chain of dirty/clean blocks
*/
static inline void link_changed(PAGECACHE_BLOCK_LINK *block,
PAGECACHE_BLOCK_LINK **phead)
{
block->prev_changed= phead;
if ((block->next_changed= *phead))
(*phead)->prev_changed= &block->next_changed;
*phead= block;
}
/*
Unlink a block from the chain of dirty/clean blocks, if it's asked for,
and link it to the chain of clean blocks for the specified file
*/
static void link_to_file_list(PAGECACHE *pagecache,
PAGECACHE_BLOCK_LINK *block,
PAGECACHE_FILE *file, my_bool unlink)
{
if (unlink)
unlink_changed(block);
link_changed(block, &pagecache->file_blocks[FILE_HASH(*file)]);
if (block->status & PCBLOCK_CHANGED)
{
block->status&= ~PCBLOCK_CHANGED;
block->rec_lsn= LSN_MAX;
pagecache->blocks_changed--;
pagecache->global_blocks_changed--;
}
}
/*
Unlink a block from the chain of clean blocks for the specified
file and link it to the chain of dirty blocks for this file
*/
static inline void link_to_changed_list(PAGECACHE *pagecache,
PAGECACHE_BLOCK_LINK *block)
{
unlink_changed(block);
link_changed(block,
&pagecache->changed_blocks[FILE_HASH(block->hash_link->file)]);
block->status|=PCBLOCK_CHANGED;
pagecache->blocks_changed++;
pagecache->global_blocks_changed++;
}
/*
Link a block to the LRU chain at the beginning or at the end of
one of two parts.
SYNOPSIS
link_block()
pagecache pointer to a page cache data structure
block pointer to the block to link to the LRU chain
hot <-> to link the block into the hot subchain
at_end <-> to link the block at the end of the subchain
RETURN VALUE
none
NOTES.
The LRU chain is represented by a curcular list of block structures.
The list is double-linked of the type (**prev,*next) type.
The LRU chain is divided into two parts - hot and warm.
There are two pointers to access the last blocks of these two
parts. The beginning of the warm part follows right after the
end of the hot part.
Only blocks of the warm part can be used for replacement.
The first block from the beginning of this subchain is always
taken for eviction (pagecache->last_used->next)
LRU chain: +------+ H O T +------+
+----| end |----...<----| beg |----+
| +------+last +------+ |
v<-link in latest hot (new end) |
| link in latest warm (new end)->^
| +------+ W A R M +------+ |
+----| beg |---->...----| end |----+
+------+ +------+ins
first for eviction
*/
static void link_block(PAGECACHE *pagecache, PAGECACHE_BLOCK_LINK *block,
my_bool hot, my_bool at_end)
{
PAGECACHE_BLOCK_LINK *ins;
PAGECACHE_BLOCK_LINK **ptr_ins;
PCBLOCK_INFO(block);
KEYCACHE_DBUG_ASSERT(! (block->hash_link && block->hash_link->requests));
#ifdef THREAD
if (!hot && pagecache->waiting_for_block.last_thread)
{
/* Signal that in the LRU warm sub-chain an available block has appeared */
struct st_my_thread_var *last_thread=
pagecache->waiting_for_block.last_thread;
struct st_my_thread_var *first_thread= last_thread->next;
struct st_my_thread_var *next_thread= first_thread;
PAGECACHE_HASH_LINK *hash_link=
(PAGECACHE_HASH_LINK *) first_thread->opt_info;
struct st_my_thread_var *thread;
do
{
thread= next_thread;
next_thread= thread->next;
/*
We notify about the event all threads that ask
for the same page as the first thread in the queue
*/
if ((PAGECACHE_HASH_LINK *) thread->opt_info == hash_link)
{
KEYCACHE_DBUG_PRINT("link_block: signal", ("thread: %ld", thread->id));
pagecache_pthread_cond_signal(&thread->suspend);
wqueue_unlink_from_queue(&pagecache->waiting_for_block, thread);
block->requests++;
}
}
while (thread != last_thread);
hash_link->block= block;
KEYCACHE_THREAD_TRACE("link_block: after signaling");
#if defined(PAGECACHE_DEBUG)
KEYCACHE_DBUG_PRINT("link_block",
("linked,unlinked block: %u status: %x #requests: %u #available: %u",
PCBLOCK_NUMBER(pagecache, block), block->status,
block->requests, pagecache->blocks_available));
#endif
return;
}
#else /* THREAD */
KEYCACHE_DBUG_ASSERT(! (!hot && pagecache->waiting_for_block.last_thread));
/* Condition not transformed using DeMorgan, to keep the text identical */
#endif /* THREAD */
ptr_ins= hot ? &pagecache->used_ins : &pagecache->used_last;
ins= *ptr_ins;
if (ins)
{
ins->next_used->prev_used= &block->next_used;
block->next_used= ins->next_used;
block->prev_used= &ins->next_used;
ins->next_used= block;
if (at_end)
*ptr_ins= block;
}
else
{
/* The LRU chain is empty */
pagecache->used_last= pagecache->used_ins= block->next_used= block;
block->prev_used= &block->next_used;
}
KEYCACHE_THREAD_TRACE("link_block");
#if defined(PAGECACHE_DEBUG)
pagecache->blocks_available++;
KEYCACHE_DBUG_PRINT("link_block",
("linked block: %u:%1u status: %x #requests: %u #available: %u",
PCBLOCK_NUMBER(pagecache, block), at_end, block->status,
block->requests, pagecache->blocks_available));
KEYCACHE_DBUG_ASSERT((ulong) pagecache->blocks_available <=
pagecache->blocks_used);
#endif
}
/*
Unlink a block from the LRU chain
SYNOPSIS
unlink_block()
pagecache pointer to a page cache data structure
block pointer to the block to unlink from the LRU chain
RETURN VALUE
none
NOTES.
See NOTES for link_block
*/
static void unlink_block(PAGECACHE *pagecache, PAGECACHE_BLOCK_LINK *block)
{
DBUG_ENTER("unlink_block");
DBUG_PRINT("unlink_block", ("unlink 0x%lx", (ulong)block));
if (block->next_used == block)
{
/* The list contains only one member */
pagecache->used_last= pagecache->used_ins= NULL;
}
else
{
block->next_used->prev_used= block->prev_used;
*block->prev_used= block->next_used;
if (pagecache->used_last == block)
pagecache->used_last= STRUCT_PTR(PAGECACHE_BLOCK_LINK,
next_used, block->prev_used);
if (pagecache->used_ins == block)
pagecache->used_ins= STRUCT_PTR(PAGECACHE_BLOCK_LINK,
next_used, block->prev_used);
}
block->next_used= NULL;
KEYCACHE_THREAD_TRACE("unlink_block");
#if defined(PAGECACHE_DEBUG)
KEYCACHE_DBUG_ASSERT(pagecache->blocks_available != 0);
pagecache->blocks_available--;
KEYCACHE_DBUG_PRINT("unlink_block",
("unlinked block: 0x%lx (%u) status: %x #requests: %u #available: %u",
(ulong)block, PCBLOCK_NUMBER(pagecache, block),
block->status,
block->requests, pagecache->blocks_available));
PCBLOCK_INFO(block);
#endif
DBUG_VOID_RETURN;
}
/*
Register requests for a block
SYNOPSIS
reg_requests()
pagecache this page cache reference
block the block we request reference
count how many requests we register (it is 1 everywhere)
NOTE
Registration of request means we are going to use this block so we exclude
it from the LRU if it is first request
*/
static void reg_requests(PAGECACHE *pagecache, PAGECACHE_BLOCK_LINK *block,
int count)
{
DBUG_ENTER("reg_requests");
DBUG_PRINT("enter", ("block: 0x%lx (%u) status: %x reqs: %u",
(ulong)block, PCBLOCK_NUMBER(pagecache, block),
block->status, block->requests));
PCBLOCK_INFO(block);
if (! block->requests)
/* First request for the block unlinks it */
unlink_block(pagecache, block);
block->requests+= count;
DBUG_VOID_RETURN;
}
/*
Unregister request for a block
linking it to the LRU chain if it's the last request
SYNOPSIS
unreg_request()
pagecache pointer to a page cache data structure
block pointer to the block to link to the LRU chain
at_end <-> to link the block at the end of the LRU chain
RETURN VALUE
none
NOTES.
Every linking to the LRU chain decrements by one a special block
counter (if it's positive). If the at_end parameter is TRUE the block is
added either at the end of warm sub-chain or at the end of hot sub-chain.
It is added to the hot subchain if its counter is zero and number of
blocks in warm sub-chain is not less than some low limit (determined by
the division_limit parameter). Otherwise the block is added to the warm
sub-chain. If the at_end parameter is FALSE the block is always added
at beginning of the warm sub-chain.
Thus a warm block can be promoted to the hot sub-chain when its counter
becomes zero for the first time.
At the same time the block at the very beginning of the hot subchain
might be moved to the beginning of the warm subchain if it stays untouched
for a too long time (this time is determined by parameter age_threshold).
*/
static void unreg_request(PAGECACHE *pagecache,
PAGECACHE_BLOCK_LINK *block, int at_end)
{
DBUG_ENTER("unreg_request");
DBUG_PRINT("enter", ("block 0x%lx (%u) status: %x reqs: %u",
(ulong)block, PCBLOCK_NUMBER(pagecache, block),
block->status, block->requests));
PCBLOCK_INFO(block);
DBUG_ASSERT(block->requests > 0);
if (! --block->requests)
{
my_bool hot;
if (block->hits_left)
block->hits_left--;
hot= !block->hits_left && at_end &&
pagecache->warm_blocks > pagecache->min_warm_blocks;
if (hot)
{
if (block->temperature == PCBLOCK_WARM)
pagecache->warm_blocks--;
block->temperature= PCBLOCK_HOT;
KEYCACHE_DBUG_PRINT("unreg_request", ("#warm_blocks: %lu",
pagecache->warm_blocks));
}
link_block(pagecache, block, hot, (my_bool)at_end);
block->last_hit_time= pagecache->time;
pagecache->time++;
block= pagecache->used_ins;
/* Check if we should link a hot block to the warm block */
if (block && pagecache->time - block->last_hit_time >
pagecache->age_threshold)
{
unlink_block(pagecache, block);
link_block(pagecache, block, 0, 0);
if (block->temperature != PCBLOCK_WARM)
{
pagecache->warm_blocks++;
block->temperature= PCBLOCK_WARM;
}
KEYCACHE_DBUG_PRINT("unreg_request", ("#warm_blocks: %lu",
pagecache->warm_blocks));
}
}
DBUG_VOID_RETURN;
}
/*
Remove a reader of the page in block
*/
static inline void remove_reader(PAGECACHE_BLOCK_LINK *block)
{
DBUG_ENTER("remove_reader");
PCBLOCK_INFO(block);
DBUG_ASSERT(block->hash_link->requests > 0);
#ifdef THREAD
if (! --block->hash_link->requests && block->condvar)
pagecache_pthread_cond_signal(block->condvar);
#else
--block->hash_link->requests;
#endif
DBUG_VOID_RETURN;
}
/*
Wait until the last reader of the page in block
signals on its termination
*/
static inline void wait_for_readers(PAGECACHE *pagecache
__attribute__((unused)),
PAGECACHE_BLOCK_LINK *block)
{
#ifdef THREAD
struct st_my_thread_var *thread= my_thread_var;
while (block->hash_link->requests)
{
KEYCACHE_DBUG_PRINT("wait_for_readers: wait",
("suspend thread: %ld block: %u",
thread->id, PCBLOCK_NUMBER(pagecache, block)));
block->condvar= &thread->suspend;
pagecache_pthread_cond_wait(&thread->suspend, &pagecache->cache_lock);
block->condvar= NULL;
}
#else
KEYCACHE_DBUG_ASSERT(block->hash_link->requests == 0);
#endif
}
/*
Add a hash link to a bucket in the hash_table
*/
static inline void link_hash(PAGECACHE_HASH_LINK **start,
PAGECACHE_HASH_LINK *hash_link)
{
if (*start)
(*start)->prev= &hash_link->next;
hash_link->next= *start;
hash_link->prev= start;
*start= hash_link;
}
/*
Remove a hash link from the hash table
*/
static void unlink_hash(PAGECACHE *pagecache, PAGECACHE_HASH_LINK *hash_link)
{
KEYCACHE_DBUG_PRINT("unlink_hash", ("fd: %u pos_ %lu #requests=%u",
(uint) hash_link->file.file, (ulong) hash_link->pageno,
hash_link->requests));
KEYCACHE_DBUG_ASSERT(hash_link->requests == 0);
if ((*hash_link->prev= hash_link->next))
hash_link->next->prev= hash_link->prev;
hash_link->block= NULL;
#ifdef THREAD
if (pagecache->waiting_for_hash_link.last_thread)
{
/* Signal that a free hash link has appeared */
struct st_my_thread_var *last_thread=
pagecache->waiting_for_hash_link.last_thread;
struct st_my_thread_var *first_thread= last_thread->next;
struct st_my_thread_var *next_thread= first_thread;
PAGECACHE_PAGE *first_page= (PAGECACHE_PAGE *) (first_thread->opt_info);
struct st_my_thread_var *thread;
hash_link->file= first_page->file;
hash_link->pageno= first_page->pageno;
do
{
PAGECACHE_PAGE *page;
thread= next_thread;
page= (PAGECACHE_PAGE *) thread->opt_info;
next_thread= thread->next;
/*
We notify about the event all threads that ask
for the same page as the first thread in the queue
*/
if (page->file.file == hash_link->file.file &&
page->pageno == hash_link->pageno)
{
KEYCACHE_DBUG_PRINT("unlink_hash: signal", ("thread %ld", thread->id));
pagecache_pthread_cond_signal(&thread->suspend);
wqueue_unlink_from_queue(&pagecache->waiting_for_hash_link, thread);
}
}
while (thread != last_thread);
link_hash(&pagecache->hash_root[PAGECACHE_HASH(pagecache,
hash_link->file,
hash_link->pageno)],
hash_link);
return;
}
#else /* THREAD */
KEYCACHE_DBUG_ASSERT(! (pagecache->waiting_for_hash_link.last_thread));
#endif /* THREAD */
hash_link->next= pagecache->free_hash_list;
pagecache->free_hash_list= hash_link;
}
/*
Get the hash link for the page if it is in the cache (do not put the
page in the cache if it is absent there)
SYNOPSIS
get_present_hash_link()
pagecache Pagecache reference
file file ID
pageno page number in the file
start where to put pointer to found hash bucket (for
direct referring it)
RETURN
found hashlink pointer
*/
static PAGECACHE_HASH_LINK *get_present_hash_link(PAGECACHE *pagecache,
PAGECACHE_FILE *file,
pgcache_page_no_t pageno,
PAGECACHE_HASH_LINK ***start)
{
reg1 PAGECACHE_HASH_LINK *hash_link;
#if defined(PAGECACHE_DEBUG)
int cnt;
#endif
DBUG_ENTER("get_present_hash_link");
KEYCACHE_DBUG_PRINT("get_present_hash_link", ("fd: %u pos: %lu",
(uint) file->file, (ulong) pageno));
/*
Find the bucket in the hash table for the pair (file, pageno);
start contains the head of the bucket list,
hash_link points to the first member of the list
*/
hash_link= *(*start= &pagecache->hash_root[PAGECACHE_HASH(pagecache,
*file, pageno)]);
#if defined(PAGECACHE_DEBUG)
cnt= 0;
#endif
/* Look for an element for the pair (file, pageno) in the bucket chain */
while (hash_link &&
(hash_link->pageno != pageno ||
hash_link->file.file != file->file))
{
hash_link= hash_link->next;
#if defined(PAGECACHE_DEBUG)
cnt++;
if (! (cnt <= pagecache->hash_links_used))
{
int i;
for (i=0, hash_link= **start ;
i < cnt ; i++, hash_link= hash_link->next)
{
KEYCACHE_DBUG_PRINT("get_present_hash_link", ("fd: %u pos: %lu",
(uint) hash_link->file.file, (ulong) hash_link->pageno));
}
}
KEYCACHE_DBUG_ASSERT(cnt <= pagecache->hash_links_used);
#endif
}
if (hash_link)
{
/* Register the request for the page */
hash_link->requests++;
}
/*
As soon as the caller will release the page cache's lock, "hash_link"
will be potentially obsolete (unusable) information.
*/
DBUG_RETURN(hash_link);
}
/*
Get the hash link for a page
*/
static PAGECACHE_HASH_LINK *get_hash_link(PAGECACHE *pagecache,
PAGECACHE_FILE *file,
pgcache_page_no_t pageno)
{
reg1 PAGECACHE_HASH_LINK *hash_link;
PAGECACHE_HASH_LINK **start;
KEYCACHE_DBUG_PRINT("get_hash_link", ("fd: %u pos: %lu",
(uint) file->file, (ulong) pageno));
restart:
/* try to find the page in the cache */
hash_link= get_present_hash_link(pagecache, file, pageno,
&start);
if (!hash_link)
{
/* There is no hash link in the hash table for the pair (file, pageno) */
if (pagecache->free_hash_list)
{
hash_link= pagecache->free_hash_list;
pagecache->free_hash_list= hash_link->next;
}
else if (pagecache->hash_links_used < pagecache->hash_links)
{
hash_link= &pagecache->hash_link_root[pagecache->hash_links_used++];
}
else
{
#ifdef THREAD
/* Wait for a free hash link */
struct st_my_thread_var *thread= my_thread_var;
PAGECACHE_PAGE page;
KEYCACHE_DBUG_PRINT("get_hash_link", ("waiting"));
page.file= *file;
page.pageno= pageno;
thread->opt_info= (void *) &page;
wqueue_link_into_queue(&pagecache->waiting_for_hash_link, thread);
KEYCACHE_DBUG_PRINT("get_hash_link: wait",
("suspend thread %ld", thread->id));
pagecache_pthread_cond_wait(&thread->suspend,
&pagecache->cache_lock);
thread->opt_info= NULL;
#else
KEYCACHE_DBUG_ASSERT(0);
#endif
DBUG_PRINT("info", ("restarting..."));
goto restart;
}
hash_link->file= *file;
hash_link->pageno= pageno;
link_hash(start, hash_link);
/* Register the request for the page */
hash_link->requests++;
}
return hash_link;
}
/*
Get a block for the file page requested by a pagecache read/write operation;
If the page is not in the cache return a free block, if there is none
return the lru block after saving its buffer if the page is dirty.
SYNOPSIS
find_block()
pagecache pointer to a page cache data structure
file handler for the file to read page from
pageno number of the page in the file
init_hits_left how initialize the block counter for the page
wrmode <-> get for writing
reg_req Register request to thye page
page_st out {PAGE_READ,PAGE_TO_BE_READ,PAGE_WAIT_TO_BE_READ}
RETURN VALUE
Pointer to the found block if successful, 0 - otherwise
NOTES.
For the page from file positioned at pageno the function checks whether
the page is in the key cache specified by the first parameter.
If this is the case it immediately returns the block.
If not, the function first chooses a block for this page. If there is
no not used blocks in the key cache yet, the function takes the block
at the very beginning of the warm sub-chain. It saves the page in that
block if it's dirty before returning the pointer to it.
The function returns in the page_st parameter the following values:
PAGE_READ - if page already in the block,
PAGE_TO_BE_READ - if it is to be read yet by the current thread
WAIT_TO_BE_READ - if it is to be read by another thread
If an error occurs THE PCBLOCK_ERROR bit is set in the block status.
It might happen that there are no blocks in LRU chain (in warm part) -
all blocks are unlinked for some read/write operations. Then the function
waits until first of this operations links any block back.
*/
static PAGECACHE_BLOCK_LINK *find_block(PAGECACHE *pagecache,
PAGECACHE_FILE *file,
pgcache_page_no_t pageno,
int init_hits_left,
my_bool wrmode,
my_bool reg_req,
int *page_st)
{
PAGECACHE_HASH_LINK *hash_link;
PAGECACHE_BLOCK_LINK *block;
int error= 0;
int page_status;
DBUG_ENTER("find_block");
KEYCACHE_THREAD_TRACE("find_block:begin");
DBUG_PRINT("enter", ("fd: %d pos: %lu wrmode: %d",
file->file, (ulong) pageno, wrmode));
KEYCACHE_DBUG_PRINT("find_block", ("fd: %d pos: %lu wrmode: %d",
file->file, (ulong) pageno,
wrmode));
#if !defined(DBUG_OFF) && defined(EXTRA_DEBUG)
DBUG_EXECUTE("check_pagecache",
test_key_cache(pagecache, "start of find_block", 0););
#endif
restart:
/* Find the hash link for the requested page (file, pageno) */
hash_link= get_hash_link(pagecache, file, pageno);
page_status= -1;
if ((block= hash_link->block) &&
block->hash_link == hash_link && (block->status & PCBLOCK_READ))
page_status= PAGE_READ;
if (wrmode && pagecache->resize_in_flush)
{
/* This is a write request during the flush phase of a resize operation */
if (page_status != PAGE_READ)
{
/* We don't need the page in the cache: we are going to write on disk */
DBUG_ASSERT(hash_link->requests > 0);
hash_link->requests--;
unlink_hash(pagecache, hash_link);
return 0;
}
if (!(block->status & PCBLOCK_IN_FLUSH))
{
DBUG_ASSERT(hash_link->requests > 0);
hash_link->requests--;
/*
Remove block to invalidate the page in the block buffer
as we are going to write directly on disk.
Although we have an exclusive lock for the updated key part
the control can be yielded by the current thread as we might
have unfinished readers of other key parts in the block
buffer. Still we are guaranteed not to have any readers
of the key part we are writing into until the block is
removed from the cache as we set the PCBLOCK_REASSIGNED
flag (see the code below that handles reading requests).
*/
free_block(pagecache, block);
return 0;
}
/* Wait until the page is flushed on disk */
DBUG_ASSERT(hash_link->requests > 0);
hash_link->requests--;
{
#ifdef THREAD
struct st_my_thread_var *thread= my_thread_var;
wqueue_add_to_queue(&block->wqueue[COND_FOR_SAVED], thread);
do
{
KEYCACHE_DBUG_PRINT("find_block: wait",
("suspend thread %ld", thread->id));
pagecache_pthread_cond_wait(&thread->suspend,
&pagecache->cache_lock);
}
while(thread->next);
#else
KEYCACHE_DBUG_ASSERT(0);
/*
Given the use of "resize_in_flush", it seems impossible
that this whole branch is ever entered in single-threaded case
because "(wrmode && pagecache->resize_in_flush)" cannot be true.
TODO: Check this, and then put the whole branch into the
"#ifdef THREAD" guard.
*/
#endif
}
/* Invalidate page in the block if it has not been done yet */
if (block->status)
free_block(pagecache, block);
return 0;
}
if (page_status == PAGE_READ &&
(block->status & (PCBLOCK_IN_SWITCH | PCBLOCK_REASSIGNED)))
{
/* This is a request for a page to be removed from cache */
KEYCACHE_DBUG_PRINT("find_block",
("request for old page in block: %u "
"wrmode: %d block->status: %d",
PCBLOCK_NUMBER(pagecache, block), wrmode,
block->status));
/*
Only reading requests can proceed until the old dirty page is flushed,
all others are to be suspended, then resubmitted
*/
if (!wrmode && !(block->status & PCBLOCK_REASSIGNED))
{
if (reg_req)
reg_requests(pagecache, block, 1);
}
else
{
DBUG_ASSERT(hash_link->requests > 0);
hash_link->requests--;
KEYCACHE_DBUG_PRINT("find_block",
("request waiting for old page to be saved"));
{
#ifdef THREAD
struct st_my_thread_var *thread= my_thread_var;
/* Put the request into the queue of those waiting for the old page */
wqueue_add_to_queue(&block->wqueue[COND_FOR_SAVED], thread);
/* Wait until the request can be resubmitted */
do
{
KEYCACHE_DBUG_PRINT("find_block: wait",
("suspend thread %ld", thread->id));
pagecache_pthread_cond_wait(&thread->suspend,
&pagecache->cache_lock);
}
while(thread->next);
#else
KEYCACHE_DBUG_ASSERT(0);
/* No parallel requests in single-threaded case */
#endif
}
KEYCACHE_DBUG_PRINT("find_block",
("request for old page resubmitted"));
DBUG_PRINT("info", ("restarting..."));
/* Resubmit the request */
goto restart;
}
block->status&= ~PCBLOCK_IN_SWITCH;
}
else
{
/* This is a request for a new page or for a page not to be removed */
if (! block)
{
/* No block is assigned for the page yet */
if (pagecache->blocks_unused)
{
if (pagecache->free_block_list)
{
/* There is a block in the free list. */
block= pagecache->free_block_list;
pagecache->free_block_list= block->next_used;
block->next_used= NULL;
}
else
{
/* There are some never used blocks, take first of them */
block= &pagecache->block_root[pagecache->blocks_used];
block->buffer= ADD_TO_PTR(pagecache->block_mem,
((ulong) pagecache->blocks_used*
pagecache->block_size),
uchar*);
pagecache->blocks_used++;
}
pagecache->blocks_unused--;
DBUG_ASSERT(block->wlocks == 0);
DBUG_ASSERT(block->pins == 0);
block->status= 0;
#ifndef DBUG_OFF
block->type= PAGECACHE_EMPTY_PAGE;
#endif
block->requests= 1;
block->temperature= PCBLOCK_COLD;
block->hits_left= init_hits_left;
block->last_hit_time= 0;
block->rec_lsn= LSN_MAX;
link_to_file_list(pagecache, block, file, 0);
block->hash_link= hash_link;
hash_link->block= block;
page_status= PAGE_TO_BE_READ;
DBUG_PRINT("info", ("page to be read set for page 0x%lx",
(ulong)block));
KEYCACHE_DBUG_PRINT("find_block",
("got free or never used block %u",
PCBLOCK_NUMBER(pagecache, block)));
}
else
{
/* There are no never used blocks, use a block from the LRU chain */
/*
Wait until a new block is added to the LRU chain;
several threads might wait here for the same page,
all of them must get the same block
*/
#ifdef THREAD
if (! pagecache->used_last)
{
struct st_my_thread_var *thread= my_thread_var;
thread->opt_info= (void *) hash_link;
wqueue_link_into_queue(&pagecache->waiting_for_block, thread);
do
{
KEYCACHE_DBUG_PRINT("find_block: wait",
("suspend thread %ld", thread->id));
pagecache_pthread_cond_wait(&thread->suspend,
&pagecache->cache_lock);
}
while (thread->next);
thread->opt_info= NULL;
}
#else
KEYCACHE_DBUG_ASSERT(pagecache->used_last);
#endif
block= hash_link->block;
if (! block)
{
/*
Take the first block from the LRU chain
unlinking it from the chain
*/
block= pagecache->used_last->next_used;
block->hits_left= init_hits_left;
block->last_hit_time= 0;
if (reg_req)
reg_requests(pagecache, block, 1);
hash_link->block= block;
}
PCBLOCK_INFO(block);
DBUG_ASSERT(block->wlocks == 0);
DBUG_ASSERT(block->pins == 0);
if (block->hash_link != hash_link &&
! (block->status & PCBLOCK_IN_SWITCH) )
{
/* this is a primary request for a new page */
DBUG_ASSERT(block->wlocks == 0);
DBUG_ASSERT(block->pins == 0);
block->status|= PCBLOCK_IN_SWITCH;
KEYCACHE_DBUG_PRINT("find_block",
("got block %u for new page",
PCBLOCK_NUMBER(pagecache, block)));
if (block->status & PCBLOCK_CHANGED)
{
/* The block contains a dirty page - push it out of the cache */
KEYCACHE_DBUG_PRINT("find_block", ("block is dirty"));
pagecache_pthread_mutex_unlock(&pagecache->cache_lock);
/*
The call is thread safe because only the current
thread might change the block->hash_link value
*/
DBUG_ASSERT(block->pins == 0);
error= pagecache_fwrite(pagecache,
&block->hash_link->file,
block->buffer,
block->hash_link->pageno,
block->type,
MYF(MY_NABP | MY_WAIT_IF_FULL));
pagecache_pthread_mutex_lock(&pagecache->cache_lock);
pagecache->global_cache_write++;
}
block->status|= PCBLOCK_REASSIGNED;
if (block->hash_link)
{
/*
Wait until all pending read requests
for this page are executed
(we could have avoided this waiting, if we had read
a page in the cache in a sweep, without yielding control)
*/
wait_for_readers(pagecache, block);
/* Remove the hash link for this page from the hash table */
unlink_hash(pagecache, block->hash_link);
/* All pending requests for this page must be resubmitted */
#ifdef THREAD
if (block->wqueue[COND_FOR_SAVED].last_thread)
wqueue_release_queue(&block->wqueue[COND_FOR_SAVED]);
#endif
}
link_to_file_list(pagecache, block, file,
(my_bool)(block->hash_link ? 1 : 0));
PCBLOCK_INFO(block);
block->status= error? PCBLOCK_ERROR : 0;
#ifndef DBUG_OFF
block->type= PAGECACHE_EMPTY_PAGE;
#endif
block->hash_link= hash_link;
page_status= PAGE_TO_BE_READ;
DBUG_PRINT("info", ("page to be read set for page 0x%lx",
(ulong)block));
KEYCACHE_DBUG_ASSERT(block->hash_link->block == block);
KEYCACHE_DBUG_ASSERT(hash_link->block->hash_link == hash_link);
}
else
{
/* This is for secondary requests for a new page only */
KEYCACHE_DBUG_PRINT("find_block",
("block->hash_link: %p hash_link: %p "
"block->status: %u", block->hash_link,
hash_link, block->status ));
page_status= (((block->hash_link == hash_link) &&
(block->status & PCBLOCK_READ)) ?
PAGE_READ : PAGE_WAIT_TO_BE_READ);
}
}
pagecache->global_cache_read++;
}
else
{
if (reg_req)
reg_requests(pagecache, block, 1);
KEYCACHE_DBUG_PRINT("find_block",
("block->hash_link: %p hash_link: %p "
"block->status: %u", block->hash_link,
hash_link, block->status ));
page_status= (((block->hash_link == hash_link) &&
(block->status & PCBLOCK_READ)) ?
PAGE_READ : PAGE_WAIT_TO_BE_READ);
}
}
KEYCACHE_DBUG_ASSERT(page_status != -1);
*page_st= page_status;
DBUG_PRINT("info",
("block: 0x%lx fd: %u pos: %lu block->status: %u page_status: %u",
(ulong) block, (uint) file->file,
(ulong) pageno, block->status, (uint) page_status));
KEYCACHE_DBUG_PRINT("find_block",
("block: 0x%lx fd: %d pos: %lu block->status: %u page_status: %d",
(ulong) block,
file->file, (ulong) pageno, block->status,
page_status));
#if !defined(DBUG_OFF) && defined(EXTRA_DEBUG)
DBUG_EXECUTE("check_pagecache",
test_key_cache(pagecache, "end of find_block",0););
#endif
KEYCACHE_THREAD_TRACE("find_block:end");
DBUG_RETURN(block);
}
static void add_pin(PAGECACHE_BLOCK_LINK *block)
{
DBUG_ENTER("add_pin");
DBUG_PRINT("enter", ("block: 0x%lx pins: %u",
(ulong) block,
block->pins));
PCBLOCK_INFO(block);
block->pins++;
#ifndef DBUG_OFF
{
PAGECACHE_PIN_INFO *info=
(PAGECACHE_PIN_INFO *)my_malloc(sizeof(PAGECACHE_PIN_INFO), MYF(0));
info->thread= my_thread_var;
info_link(&block->pin_list, info);
}
#endif
DBUG_VOID_RETURN;
}
static void remove_pin(PAGECACHE_BLOCK_LINK *block)
{
DBUG_ENTER("remove_pin");
DBUG_PRINT("enter", ("block: 0x%lx pins: %u",
(ulong) block,
block->pins));
PCBLOCK_INFO(block);
DBUG_ASSERT(block->pins > 0);
block->pins--;
#ifndef DBUG_OFF
{
PAGECACHE_PIN_INFO *info= info_find(block->pin_list, my_thread_var);
DBUG_ASSERT(info != 0);
info_unlink(info);
my_free((uchar*) info, MYF(0));
}
#endif
DBUG_VOID_RETURN;
}
#ifndef DBUG_OFF
static void info_add_lock(PAGECACHE_BLOCK_LINK *block, my_bool wl)
{
PAGECACHE_LOCK_INFO *info=
(PAGECACHE_LOCK_INFO *)my_malloc(sizeof(PAGECACHE_LOCK_INFO), MYF(0));
info->thread= my_thread_var;
info->write_lock= wl;
info_link((PAGECACHE_PIN_INFO **)&block->lock_list,
(PAGECACHE_PIN_INFO *)info);
}
static void info_remove_lock(PAGECACHE_BLOCK_LINK *block)
{
PAGECACHE_LOCK_INFO *info=
(PAGECACHE_LOCK_INFO *)info_find((PAGECACHE_PIN_INFO *)block->lock_list,
my_thread_var);
DBUG_ASSERT(info != 0);
info_unlink((PAGECACHE_PIN_INFO *)info);
my_free((uchar*)info, MYF(0));
}
static void info_change_lock(PAGECACHE_BLOCK_LINK *block, my_bool wl)
{
PAGECACHE_LOCK_INFO *info=
(PAGECACHE_LOCK_INFO *)info_find((PAGECACHE_PIN_INFO *)block->lock_list,
my_thread_var);
DBUG_ASSERT(info != 0);
DBUG_ASSERT(info->write_lock != wl);
info->write_lock= wl;
}
#else
#define info_add_lock(B,W)
#define info_remove_lock(B)
#define info_change_lock(B,W)
#endif
/*
Put on the block write lock
SYNOPSIS
get_wrlock()
pagecache pointer to a page cache data structure
block the block to work with
user_file Unique handler per handler file. Used to check if
we request many write locks withing the same
statement
RETURN
0 - OK
1 - Can't lock this block, need retry
*/
static my_bool get_wrlock(PAGECACHE *pagecache,
PAGECACHE_BLOCK_LINK *block,
PAGECACHE_FILE *user_file)
{
PAGECACHE_FILE file= block->hash_link->file;
pgcache_page_no_t pageno= block->hash_link->pageno;
DBUG_ENTER("get_wrlock");
DBUG_PRINT("info", ("the block 0x%lx "
"files %d(%d) pages %d(%d)",
(ulong)block,
file.file, block->hash_link->file.file,
pageno, block->hash_link->pageno));
PCBLOCK_INFO(block);
while (block->wlocks && block->write_locker != user_file)
{
/* Lock failed we will wait */
#ifdef THREAD
struct st_my_thread_var *thread= my_thread_var;
DBUG_PRINT("info", ("fail to lock, waiting... 0x%lx", (ulong)block));
wqueue_add_to_queue(&block->wqueue[COND_FOR_WRLOCK], thread);
dec_counter_for_resize_op(pagecache);
do
{
KEYCACHE_DBUG_PRINT("get_wrlock: wait",
("suspend thread %ld", thread->id));
pagecache_pthread_cond_wait(&thread->suspend,
&pagecache->cache_lock);
}
while(thread->next);
#else
DBUG_ASSERT(0);
#endif
PCBLOCK_INFO(block);
if ((block->status & (PCBLOCK_REASSIGNED | PCBLOCK_IN_SWITCH)) ||
file.file != block->hash_link->file.file ||
pageno != block->hash_link->pageno)
{
DBUG_PRINT("info", ("the block 0x%lx changed => need retry"
"status %x files %d != %d or pages %d !=%d",
(ulong)block, block->status,
file.file, block->hash_link->file.file,
pageno, block->hash_link->pageno));
DBUG_RETURN(1);
}
}
/* we are doing it by global cache mutex protection, so it is OK */
block->wlocks++;
block->write_locker= user_file;
DBUG_PRINT("info", ("WR lock set, block 0x%lx", (ulong)block));
DBUG_RETURN(0);
}
/*
Remove write lock from the block
SYNOPSIS
release_wrlock()
pagecache pointer to a page cache data structure
block the block to work with
RETURN
0 - OK
*/
static void release_wrlock(PAGECACHE_BLOCK_LINK *block)
{
DBUG_ENTER("release_wrlock");
PCBLOCK_INFO(block);
DBUG_ASSERT(block->wlocks > 0);
DBUG_ASSERT(block->pins > 0);
block->wlocks--;
if (block->wlocks > 0)
DBUG_VOID_RETURN; /* Multiple write locked */
DBUG_PRINT("info", ("WR lock reset, block 0x%lx", (ulong)block));
#ifdef THREAD
/* release all threads waiting for write lock */
if (block->wqueue[COND_FOR_WRLOCK].last_thread)
wqueue_release_queue(&block->wqueue[COND_FOR_WRLOCK]);
#endif
PCBLOCK_INFO(block);
DBUG_VOID_RETURN;
}
/*
Try to lock/unlock and pin/unpin the block
SYNOPSIS
make_lock_and_pin()
pagecache pointer to a page cache data structure
block the block to work with
lock lock change mode
pin pinchange mode
file File handler requesting pin
RETURN
0 - OK
1 - Try to lock the block failed
*/
static my_bool make_lock_and_pin(PAGECACHE *pagecache,
PAGECACHE_BLOCK_LINK *block,
enum pagecache_page_lock lock,
enum pagecache_page_pin pin,
PAGECACHE_FILE *file)
{
DBUG_ENTER("make_lock_and_pin");
DBUG_PRINT("enter", ("block: 0x%lx", (ulong)block));
#ifndef DBUG_OFF
if (block)
{
DBUG_PRINT("enter", ("block: 0x%lx (%u) wrlocks: %u pins: %u lock: %s pin: %s",
(ulong)block, PCBLOCK_NUMBER(pagecache, block),
block->wlocks,
block->pins,
page_cache_page_lock_str[lock],
page_cache_page_pin_str[pin]));
PCBLOCK_INFO(block);
}
#endif
switch (lock) {
case PAGECACHE_LOCK_WRITE: /* free -> write */
/* Writelock and pin the buffer */
if (get_wrlock(pagecache, block, file))
{
/* can't lock => need retry */
goto retry;
}
/* The cache is locked so nothing afraid of */
add_pin(block);
info_add_lock(block, 1);
break;
case PAGECACHE_LOCK_WRITE_TO_READ: /* write -> read */
case PAGECACHE_LOCK_WRITE_UNLOCK: /* write -> free */
/*
Removes write lock and puts read lock (which is nothing in our
implementation)
*/
release_wrlock(block);
/* fall through */
case PAGECACHE_LOCK_READ_UNLOCK: /* read -> free */
case PAGECACHE_LOCK_LEFT_READLOCKED: /* read -> read */
if (pin == PAGECACHE_UNPIN)
{
remove_pin(block);
}
if (lock == PAGECACHE_LOCK_WRITE_TO_READ)
{
info_change_lock(block, 0);
}
else if (lock == PAGECACHE_LOCK_WRITE_UNLOCK ||
lock == PAGECACHE_LOCK_READ_UNLOCK)
{
info_remove_lock(block);
}
break;
case PAGECACHE_LOCK_READ: /* free -> read */
if (pin == PAGECACHE_PIN)
{
/* The cache is locked so nothing afraid off */
add_pin(block);
}
info_add_lock(block, 0);
break;
case PAGECACHE_LOCK_LEFT_UNLOCKED: /* free -> free */
case PAGECACHE_LOCK_LEFT_WRITELOCKED: /* write -> write */
break; /* do nothing */
default:
DBUG_ASSERT(0); /* Never should happened */
}
#ifndef DBUG_OFF
if (block)
PCBLOCK_INFO(block);
#endif
DBUG_RETURN(0);
retry:
DBUG_PRINT("INFO", ("Retry block 0x%lx", (ulong)block));
PCBLOCK_INFO(block);
DBUG_ASSERT(block->hash_link->requests > 0);
block->hash_link->requests--;
DBUG_ASSERT(block->requests > 0);
unreg_request(pagecache, block, 1);
PCBLOCK_INFO(block);
DBUG_RETURN(1);
}
/*
Read into a key cache block buffer from disk.
SYNOPSIS
read_block()
pagecache pointer to a page cache data structure
block block to which buffer the data is to be read
primary <-> the current thread will read the data
validator validator of read from the disk data
validator_data pointer to the data need by the validator
RETURN VALUE
None
NOTES.
The function either reads a page data from file to the block buffer,
or waits until another thread reads it. What page to read is determined
by a block parameter - reference to a hash link for this page.
If an error occurs THE PCBLOCK_ERROR bit is set in the block status.
*/
static void read_block(PAGECACHE *pagecache,
PAGECACHE_BLOCK_LINK *block,
my_bool primary,
pagecache_disk_read_validator validator,
uchar* validator_data)
{
uint got_length;
/* On entry cache_lock is locked */
DBUG_ENTER("read_block");
if (primary)
{
/*
This code is executed only by threads
that submitted primary requests
*/
DBUG_PRINT("read_block",
("page to be read by primary request"));
/* Page is not in buffer yet, is to be read from disk */
pagecache_pthread_mutex_unlock(&pagecache->cache_lock);
/*
Here other threads may step in and register as secondary readers.
They will register in block->wqueue[COND_FOR_REQUESTED].
*/
got_length= pagecache_fread(pagecache, &block->hash_link->file,
block->buffer,
block->hash_link->pageno, MYF(0));
pagecache_pthread_mutex_lock(&pagecache->cache_lock);
if (got_length < pagecache->block_size)
block->status|= PCBLOCK_ERROR;
else
block->status= PCBLOCK_READ;
if (validator != NULL &&
(*validator)(block->buffer, validator_data))
block->status|= PCBLOCK_ERROR;
DBUG_PRINT("read_block",
("primary request: new page in cache"));
/* Signal that all pending requests for this page now can be processed */
#ifdef THREAD
if (block->wqueue[COND_FOR_REQUESTED].last_thread)
wqueue_release_queue(&block->wqueue[COND_FOR_REQUESTED]);
#endif
}
else
{
/*
This code is executed only by threads
that submitted secondary requests
*/
DBUG_PRINT("read_block",
("secondary request waiting for new page to be read"));
{
#ifdef THREAD
struct st_my_thread_var *thread= my_thread_var;
/* Put the request into a queue and wait until it can be processed */
wqueue_add_to_queue(&block->wqueue[COND_FOR_REQUESTED], thread);
do
{
DBUG_PRINT("read_block: wait",
("suspend thread %ld", thread->id));
pagecache_pthread_cond_wait(&thread->suspend,
&pagecache->cache_lock);
}
while (thread->next);
#else
KEYCACHE_DBUG_ASSERT(0);
/* No parallel requests in single-threaded case */
#endif
}
DBUG_PRINT("read_block",
("secondary request: new page in cache"));
}
DBUG_VOID_RETURN;
}
/**
@brief Set LSN on the page to the given one if the given LSN is bigger
@param pagecache pointer to a page cache data structure
@param lsn LSN to set
@param block block to check and set
*/
static void check_and_set_lsn(PAGECACHE *pagecache,
LSN lsn, PAGECACHE_BLOCK_LINK *block)
{
LSN old;
DBUG_ENTER("check_and_set_lsn");
DBUG_ASSERT(block->type == PAGECACHE_LSN_PAGE);
old= lsn_korr(block->buffer + PAGE_LSN_OFFSET);
DBUG_PRINT("info", ("old lsn: (%lu, 0x%lx) new lsn: (%lu, 0x%lx)",
LSN_IN_PARTS(old), LSN_IN_PARTS(lsn)));
if (cmp_translog_addr(lsn, old) > 0)
{
DBUG_ASSERT(block->type != PAGECACHE_READ_UNKNOWN_PAGE);
lsn_store(block->buffer + PAGE_LSN_OFFSET, lsn);
/* we stored LSN in page so we dirtied it */
if (!(block->status & PCBLOCK_CHANGED))
link_to_changed_list(pagecache, block);
}
DBUG_VOID_RETURN;
}
/*
Unlock/unpin page and put LSN stamp if it need
SYNOPSIS
pagecache_unlock()
pagecache pointer to a page cache data structure
file handler for the file for the block of data to be read
pageno number of the block of data in the file
lock lock change
pin pin page
first_REDO_LSN_for_page do not set it if it is zero
lsn if it is not LSN_IMPOSSIBLE (0) and it
is bigger then LSN on the page it will be written on
the page
NOTE
Pininig uses requests registration mechanism it works following way:
| beginnig | ending |
| of func. | of func. |
----------------------------+-------------+---------------+
PAGECACHE_PIN_LEFT_PINNED | - | - |
PAGECACHE_PIN_LEFT_UNPINNED | reg request | unreg request |
PAGECACHE_PIN | reg request | - |
PAGECACHE_UNPIN | - | unreg request |
*/
void pagecache_unlock(PAGECACHE *pagecache,
PAGECACHE_FILE *file,
pgcache_page_no_t pageno,
enum pagecache_page_lock lock,
enum pagecache_page_pin pin,
LSN first_REDO_LSN_for_page,
LSN lsn)
{
PAGECACHE_BLOCK_LINK *block;
int page_st;
DBUG_ENTER("pagecache_unlock");
DBUG_PRINT("enter", ("fd: %u page: %lu %s %s",
(uint) file->file, (ulong) pageno,
page_cache_page_lock_str[lock],
page_cache_page_pin_str[pin]));
/* we do not allow any lock/pin increasing here */
DBUG_ASSERT(pin != PAGECACHE_PIN);
DBUG_ASSERT(lock != PAGECACHE_LOCK_READ);
DBUG_ASSERT(lock != PAGECACHE_LOCK_WRITE);
pagecache_pthread_mutex_lock(&pagecache->cache_lock);
/*
As soon as we keep lock cache can be used, and we have lock because want
to unlock.
*/
DBUG_ASSERT(pagecache->can_be_used);
inc_counter_for_resize_op(pagecache);
/* See NOTE for pagecache_unlock about registering requests */
block= find_block(pagecache, file, pageno, 0, 0,
test(pin == PAGECACHE_PIN_LEFT_UNPINNED), &page_st);
PCBLOCK_INFO(block);
DBUG_ASSERT(block != 0 && page_st == PAGE_READ);
if (first_REDO_LSN_for_page)
{
DBUG_ASSERT(lock == PAGECACHE_LOCK_WRITE_UNLOCK);
DBUG_ASSERT(pin == PAGECACHE_UNPIN);
if (block->rec_lsn == LSN_MAX)
block->rec_lsn= first_REDO_LSN_for_page;
else
DBUG_ASSERT(cmp_translog_addr(block->rec_lsn,
first_REDO_LSN_for_page) <= 0);
}
if (lsn != LSN_IMPOSSIBLE)
check_and_set_lsn(pagecache, lsn, block);
if (make_lock_and_pin(pagecache, block, lock, pin, file))
{
DBUG_ASSERT(0); /* should not happend */
}
remove_reader(block);
/*
Link the block into the LRU chain if it's the last submitted request
for the block and block will not be pinned.
See NOTE for pagecache_unlock about registering requests.
*/
if (pin != PAGECACHE_PIN_LEFT_PINNED)
unreg_request(pagecache, block, 1);
dec_counter_for_resize_op(pagecache);
pagecache_pthread_mutex_unlock(&pagecache->cache_lock);
DBUG_VOID_RETURN;
}
/*
Unpin page
SYNOPSIS
pagecache_unpin()
pagecache pointer to a page cache data structure
file handler for the file for the block of data to be read
pageno number of the block of data in the file
lsn if it is not LSN_IMPOSSIBLE (0) and it
is bigger then LSN on the page it will be written on
the page
*/
void pagecache_unpin(PAGECACHE *pagecache,
PAGECACHE_FILE *file,
pgcache_page_no_t pageno,
LSN lsn)
{
PAGECACHE_BLOCK_LINK *block;
int page_st;
DBUG_ENTER("pagecache_unpin");
DBUG_PRINT("enter", ("fd: %u page: %lu",
(uint) file->file, (ulong) pageno));
pagecache_pthread_mutex_lock(&pagecache->cache_lock);
/*
As soon as we keep lock cache can be used, and we have lock bacause want
aunlock.
*/
DBUG_ASSERT(pagecache->can_be_used);
inc_counter_for_resize_op(pagecache);
/* See NOTE for pagecache_unlock about registering requests */
block= find_block(pagecache, file, pageno, 0, 0, 0, &page_st);
DBUG_ASSERT(block != 0);
DBUG_ASSERT(page_st == PAGE_READ);
if (lsn != LSN_IMPOSSIBLE)
check_and_set_lsn(pagecache, lsn, block);
/*
we can just unpin only with keeping read lock because:
a) we can't pin without any lock
b) we can't unpin keeping write lock
*/
if (make_lock_and_pin(pagecache, block,
PAGECACHE_LOCK_LEFT_READLOCKED,
PAGECACHE_UNPIN, file))
DBUG_ASSERT(0); /* should not happend */
remove_reader(block);
/*
Link the block into the LRU chain if it's the last submitted request
for the block and block will not be pinned.
See NOTE for pagecache_unlock about registering requests
*/
unreg_request(pagecache, block, 1);
dec_counter_for_resize_op(pagecache);
pagecache_pthread_mutex_unlock(&pagecache->cache_lock);
DBUG_VOID_RETURN;
}
/*
Unlock/unpin page and put LSN stamp if it need
(uses direct block/page pointer)
SYNOPSIS
pagecache_unlock_by_link()
pagecache pointer to a page cache data structure
link direct link to page (returned by read or write)
lock lock change
pin pin page
first_REDO_LSN_for_page do not set it if it is LSN_IMPOSSIBLE (0)
lsn if it is not LSN_IMPOSSIBLE and it is bigger then
LSN on the page it will be written on the page
*/
void pagecache_unlock_by_link(PAGECACHE *pagecache,
PAGECACHE_BLOCK_LINK *block,
enum pagecache_page_lock lock,
enum pagecache_page_pin pin,
LSN first_REDO_LSN_for_page,
LSN lsn)
{
DBUG_ENTER("pagecache_unlock_by_link");
DBUG_PRINT("enter", ("block: 0x%lx fd: %u page: %lu %s %s",
(ulong) block,
(uint) block->hash_link->file.file,
(ulong) block->hash_link->pageno,
page_cache_page_lock_str[lock],
page_cache_page_pin_str[pin]));
/*
We do not allow any lock/pin increasing here and page can't be
unpinned because we use direct link.
*/
DBUG_ASSERT(pin != PAGECACHE_PIN);
DBUG_ASSERT(pin != PAGECACHE_PIN_LEFT_UNPINNED);
DBUG_ASSERT(lock != PAGECACHE_LOCK_READ);
DBUG_ASSERT(lock != PAGECACHE_LOCK_WRITE);
if (pin == PAGECACHE_PIN_LEFT_UNPINNED &&
lock == PAGECACHE_LOCK_READ_UNLOCK)
{
/* block do not need here so we do not provide it */
if (make_lock_and_pin(pagecache, 0, lock, pin, 0))
DBUG_ASSERT(0); /* should not happend */
DBUG_VOID_RETURN;
}
pagecache_pthread_mutex_lock(&pagecache->cache_lock);
/*
As soon as we keep lock cache can be used, and we have lock because want
unlock.
*/
DBUG_ASSERT(pagecache->can_be_used);
inc_counter_for_resize_op(pagecache);
if (first_REDO_LSN_for_page != LSN_IMPOSSIBLE)
{
/*
LOCK_READ_UNLOCK is ok here as the page may have first locked
with WRITE lock that was temporarly converted to READ lock before
it's unpinned
*/
DBUG_ASSERT(lock == PAGECACHE_LOCK_WRITE_UNLOCK ||
lock == PAGECACHE_LOCK_READ_UNLOCK);
DBUG_ASSERT(pin == PAGECACHE_UNPIN);
if (block->rec_lsn == LSN_MAX)
block->rec_lsn= first_REDO_LSN_for_page;
else
DBUG_ASSERT(cmp_translog_addr(block->rec_lsn,
first_REDO_LSN_for_page) <= 0);
}
if (lsn != LSN_IMPOSSIBLE)
check_and_set_lsn(pagecache, lsn, block);
if (make_lock_and_pin(pagecache, block, lock, pin, 0))
DBUG_ASSERT(0); /* should not happend */
/*
Link the block into the LRU chain if it's the last submitted request
for the block and block will not be pinned.
See NOTE for pagecache_unlock about registering requests.
*/
if (pin != PAGECACHE_PIN_LEFT_PINNED)
unreg_request(pagecache, block, 1);
dec_counter_for_resize_op(pagecache);
pagecache_pthread_mutex_unlock(&pagecache->cache_lock);
DBUG_VOID_RETURN;
}
/*
Unpin page
(uses direct block/page pointer)
SYNOPSIS
pagecache_unpin_by_link()
pagecache pointer to a page cache data structure
link direct link to page (returned by read or write)
lsn if it is not LSN_IMPOSSIBLE (0) and it
is bigger then LSN on the page it will be written on
the page
*/
void pagecache_unpin_by_link(PAGECACHE *pagecache,
PAGECACHE_BLOCK_LINK *block,
LSN lsn)
{
DBUG_ENTER("pagecache_unpin_by_link");
DBUG_PRINT("enter", ("block: 0x%lx fd: %u page: %lu",
(ulong) block,
(uint) block->hash_link->file.file,
(ulong) block->hash_link->pageno));
pagecache_pthread_mutex_lock(&pagecache->cache_lock);
/*
As soon as we keep lock cache can be used, and we have lock because want
unlock.
*/
DBUG_ASSERT(pagecache->can_be_used);
inc_counter_for_resize_op(pagecache);
if (lsn != LSN_IMPOSSIBLE)
check_and_set_lsn(pagecache, lsn, block);
/*
We can just unpin only with keeping read lock because:
a) we can't pin without any lock
b) we can't unpin keeping write lock
*/
if (make_lock_and_pin(pagecache, block,
PAGECACHE_LOCK_LEFT_READLOCKED,
PAGECACHE_UNPIN, 0))
DBUG_ASSERT(0); /* should not happend */
/*
Link the block into the LRU chain if it's the last submitted request
for the block and block will not be pinned.
See NOTE for pagecache_unlock about registering requests.
*/
unreg_request(pagecache, block, 1);
dec_counter_for_resize_op(pagecache);
pagecache_pthread_mutex_unlock(&pagecache->cache_lock);
DBUG_VOID_RETURN;
}
/*
Read a block of data from a cached file into a buffer;
SYNOPSIS
pagecache_valid_read()
pagecache pointer to a page cache data structure
file handler for the file for the block of data to be read
pageno number of the block of data in the file
level determines the weight of the data
buff buffer to where the data must be placed
type type of the page
lock lock change
link link to the page if we pin it
validator validator of read from the disk data
validator_data pointer to the data need by the validator
RETURN VALUE
Returns address from where the data is placed if successful, 0 - otherwise.
Pin will be chosen according to lock parameter (see lock_to_pin)
*/
static enum pagecache_page_pin lock_to_pin[2][8]=
{
{
PAGECACHE_PIN_LEFT_UNPINNED /*PAGECACHE_LOCK_LEFT_UNLOCKED*/,
PAGECACHE_PIN_LEFT_UNPINNED /*PAGECACHE_LOCK_LEFT_READLOCKED*/,
PAGECACHE_PIN_LEFT_PINNED /*PAGECACHE_LOCK_LEFT_WRITELOCKED*/,
PAGECACHE_PIN_LEFT_UNPINNED /*PAGECACHE_LOCK_READ*/,
PAGECACHE_PIN /*PAGECACHE_LOCK_WRITE*/,
PAGECACHE_PIN_LEFT_UNPINNED /*PAGECACHE_LOCK_READ_UNLOCK*/,
PAGECACHE_UNPIN /*PAGECACHE_LOCK_WRITE_UNLOCK*/,
PAGECACHE_UNPIN /*PAGECACHE_LOCK_WRITE_TO_READ*/
},
{
PAGECACHE_PIN_LEFT_UNPINNED /*PAGECACHE_LOCK_LEFT_UNLOCKED*/,
PAGECACHE_PIN_LEFT_PINNED /*PAGECACHE_LOCK_LEFT_READLOCKED*/,
PAGECACHE_PIN_LEFT_PINNED /*PAGECACHE_LOCK_LEFT_WRITELOCKED*/,
PAGECACHE_PIN /*PAGECACHE_LOCK_READ*/,
PAGECACHE_PIN /*PAGECACHE_LOCK_WRITE*/,
PAGECACHE_PIN_LEFT_UNPINNED /*PAGECACHE_LOCK_READ_UNLOCK*/,
PAGECACHE_UNPIN /*PAGECACHE_LOCK_WRITE_UNLOCK*/,
PAGECACHE_PIN_LEFT_PINNED /*PAGECACHE_LOCK_WRITE_TO_READ*/
}
};
uchar *pagecache_valid_read(PAGECACHE *pagecache,
PAGECACHE_FILE *file,
pgcache_page_no_t pageno,
uint level,
uchar *buff,
enum pagecache_page_type type,
enum pagecache_page_lock lock,
PAGECACHE_BLOCK_LINK **link,
pagecache_disk_read_validator validator,
uchar* validator_data)
{
int error= 0;
enum pagecache_page_pin pin= lock_to_pin[test(buff==0)][lock];
PAGECACHE_BLOCK_LINK *fake_link;
DBUG_ENTER("pagecache_valid_read");
DBUG_PRINT("enter", ("fd: %u page: %lu buffer: 0x%lx level: %u "
"t:%s %s %s",
(uint) file->file, (ulong) pageno,
(ulong) buff, level,
page_cache_page_type_str[type],
page_cache_page_lock_str[lock],
page_cache_page_pin_str[pin]));
DBUG_ASSERT(buff != 0 || (buff == 0 && (pin == PAGECACHE_PIN ||
pin == PAGECACHE_PIN_LEFT_PINNED)));
if (!link)
link= &fake_link;
*link= 0; /* Catch errors */
restart:
if (pagecache->can_be_used)
{
/* Key cache is used */
PAGECACHE_BLOCK_LINK *block;
uint status;
int page_st;
pagecache_pthread_mutex_lock(&pagecache->cache_lock);
if (!pagecache->can_be_used)
{
pagecache_pthread_mutex_unlock(&pagecache->cache_lock);
goto no_key_cache;
}
inc_counter_for_resize_op(pagecache);
pagecache->global_cache_r_requests++;
/* See NOTE for pagecache_unlock about registering requests. */
block= find_block(pagecache, file, pageno, level,
test(lock == PAGECACHE_LOCK_WRITE),
test((pin == PAGECACHE_PIN_LEFT_UNPINNED) ||
(pin == PAGECACHE_PIN)),
&page_st);
DBUG_ASSERT(block->type == PAGECACHE_EMPTY_PAGE ||
block->type == type ||
type == PAGECACHE_LSN_PAGE ||
type == PAGECACHE_READ_UNKNOWN_PAGE ||
block->type == PAGECACHE_READ_UNKNOWN_PAGE);
if (type != PAGECACHE_READ_UNKNOWN_PAGE ||
block->type == PAGECACHE_EMPTY_PAGE)
block->type= type;
if (((block->status & PCBLOCK_ERROR) == 0) && (page_st != PAGE_READ))
{
DBUG_PRINT("info", ("read block 0x%lx", (ulong)block));
/* The requested page is to be read into the block buffer */
read_block(pagecache, block,
(my_bool)(page_st == PAGE_TO_BE_READ),
validator, validator_data);
DBUG_PRINT("info", ("read is done"));
}
if (make_lock_and_pin(pagecache, block, lock, pin, file))
{
/*
We failed to write lock the block, cache is unlocked,
we will try to get the block again.
*/
pagecache_pthread_mutex_unlock(&pagecache->cache_lock);
DBUG_PRINT("info", ("restarting..."));
goto restart;
}
status= block->status;
if (!buff)
{
buff= block->buffer;
/* if we lock for write we must link the block to changed blocks */
if ((lock == PAGECACHE_LOCK_WRITE ||
lock == PAGECACHE_LOCK_LEFT_WRITELOCKED) &&
!(block->status & PCBLOCK_CHANGED))
link_to_changed_list(pagecache, block);
}
else
{
if (!(status & PCBLOCK_ERROR))
{
#if !defined(SERIALIZED_READ_FROM_CACHE)
pagecache_pthread_mutex_unlock(&pagecache->cache_lock);
#endif
DBUG_ASSERT((pagecache->block_size & 511) == 0);
/* Copy data from the cache buffer */
bmove512(buff, block->buffer, pagecache->block_size);
#if !defined(SERIALIZED_READ_FROM_CACHE)
pagecache_pthread_mutex_lock(&pagecache->cache_lock);
#endif
}
}
remove_reader(block);
/*
Link the block into the LRU chain if it's the last submitted request
for the block and block will not be pinned.
See NOTE for pagecache_unlock about registering requests.
*/
if (pin == PAGECACHE_PIN_LEFT_UNPINNED || pin == PAGECACHE_UNPIN)
unreg_request(pagecache, block, 1);
else
*link= block;
dec_counter_for_resize_op(pagecache);
pagecache_pthread_mutex_unlock(&pagecache->cache_lock);
if (status & PCBLOCK_ERROR)
DBUG_RETURN((uchar *) 0);
DBUG_RETURN(buff);
}
no_key_cache: /* Key cache is not used */
/* We can't use mutex here as the key cache may not be initialized */
pagecache->global_cache_r_requests++;
pagecache->global_cache_read++;
if (pagecache_fread(pagecache, file, (uchar*) buff, pageno, MYF(MY_NABP)))
error= 1;
DBUG_RETURN(error ? (uchar*) 0 : buff);
}
/*
Delete page from the buffer
SYNOPSIS
pagecache_delete()
pagecache pointer to a page cache data structure
file handler for the file for the block of data to be read
pageno number of the block of data in the file
lock lock change
flush flush page if it is dirty
RETURN VALUE
0 - deleted or was not present at all
1 - error
NOTES.
lock can be only PAGECACHE_LOCK_LEFT_WRITELOCKED (page was write locked
before) or PAGECACHE_LOCK_WRITE (delete will write lock page before delete)
*/
my_bool pagecache_delete(PAGECACHE *pagecache,
PAGECACHE_FILE *file,
pgcache_page_no_t pageno,
enum pagecache_page_lock lock,
my_bool flush)
{
int error= 0;
enum pagecache_page_pin pin= lock_to_pin[0][lock];
DBUG_ENTER("pagecache_delete");
DBUG_PRINT("enter", ("fd: %u page: %lu %s %s",
(uint) file->file, (ulong) pageno,
page_cache_page_lock_str[lock],
page_cache_page_pin_str[pin]));
DBUG_ASSERT(lock == PAGECACHE_LOCK_WRITE ||
lock == PAGECACHE_LOCK_LEFT_WRITELOCKED);
DBUG_ASSERT(pin == PAGECACHE_PIN ||
pin == PAGECACHE_PIN_LEFT_PINNED);
restart:
if (pagecache->can_be_used)
{
/* Key cache is used */
reg1 PAGECACHE_BLOCK_LINK *block;
PAGECACHE_HASH_LINK **unused_start, *link;
pagecache_pthread_mutex_lock(&pagecache->cache_lock);
if (!pagecache->can_be_used)
goto end;
inc_counter_for_resize_op(pagecache);
link= get_present_hash_link(pagecache, file, pageno, &unused_start);
if (!link)
{
DBUG_PRINT("info", ("There is no such page in the cache"));
pagecache_pthread_mutex_unlock(&pagecache->cache_lock);
DBUG_RETURN(0);
}
block= link->block;
/* See NOTE for pagecache_unlock about registering requests. */
if (pin == PAGECACHE_PIN)
reg_requests(pagecache, block, 1);
DBUG_ASSERT(block != 0);
if (make_lock_and_pin(pagecache, block, lock, pin, file))
{
/*
We failed to writelock the block, cache is unlocked, and last write
lock is released, we will try to get the block again.
*/
pagecache_pthread_mutex_unlock(&pagecache->cache_lock);
DBUG_PRINT("info", ("restarting..."));
goto restart;
}
if (block->status & PCBLOCK_CHANGED)
{
if (flush)
{
/* The block contains a dirty page - push it out of the cache */
KEYCACHE_DBUG_PRINT("find_block", ("block is dirty"));
pagecache_pthread_mutex_unlock(&pagecache->cache_lock);
/*
The call is thread safe because only the current
thread might change the block->hash_link value
*/
DBUG_ASSERT(block->pins == 1);
error= pagecache_fwrite(pagecache,
&block->hash_link->file,
block->buffer,
block->hash_link->pageno,
block->type,
MYF(MY_NABP | MY_WAIT_IF_FULL));
pagecache_pthread_mutex_lock(&pagecache->cache_lock);
pagecache->global_cache_write++;
if (error)
{
block->status|= PCBLOCK_ERROR;
goto err;
}
}
pagecache->blocks_changed--;
pagecache->global_blocks_changed--;
/*
free_block() will change the status and rec_lsn of the block so no
need to change them here.
*/
}
/* Cache is locked, so we can relese page before freeing it */
make_lock_and_pin(pagecache, block,
PAGECACHE_LOCK_WRITE_UNLOCK,
PAGECACHE_UNPIN, file);
DBUG_ASSERT(link->requests > 0);
link->requests--;
/* See NOTE for pagecache_unlock about registering requests. */
free_block(pagecache, block);
err:
dec_counter_for_resize_op(pagecache);
end:
pagecache_pthread_mutex_unlock(&pagecache->cache_lock);
}
DBUG_RETURN(error);
}
my_bool pagecache_delete_pages(PAGECACHE *pagecache,
PAGECACHE_FILE *file,
pgcache_page_no_t pageno,
uint page_count,
enum pagecache_page_lock lock,
my_bool flush)
{
ulong page_end;
DBUG_ENTER("pagecache_delete_pages");
DBUG_ASSERT(page_count > 0);
page_end= pageno + page_count;
do
{
if (pagecache_delete(pagecache, file, pageno,
lock, flush))
DBUG_RETURN(1);
} while (++pageno != page_end);
DBUG_RETURN(0);
}
/*
Write a buffer into a cached file.
SYNOPSIS
pagecache_write_part()
pagecache pointer to a page cache data structure
file handler for the file to write data to
pageno number of the block of data in the file
level determines the weight of the data
buff buffer with the data
type type of the page
lock lock change
pin pin page
write_mode how to write page
link link to the page if we pin it
RETURN VALUE
0 if a success, 1 - otherwise.
*/
/* description of how to change lock before and after write */
struct write_lock_change
{
int need_lock_change; /* need changing of lock at the end of write */
enum pagecache_page_lock new_lock; /* lock at the beginning */
enum pagecache_page_lock unlock_lock; /* lock at the end */
};
static struct write_lock_change write_lock_change_table[]=
{
{1,
PAGECACHE_LOCK_WRITE,
PAGECACHE_LOCK_WRITE_UNLOCK} /*PAGECACHE_LOCK_LEFT_UNLOCKED*/,
{0, /*unsupported (we can't write having the block read locked) */
PAGECACHE_LOCK_LEFT_UNLOCKED,
PAGECACHE_LOCK_LEFT_UNLOCKED} /*PAGECACHE_LOCK_LEFT_READLOCKED*/,
{0, PAGECACHE_LOCK_LEFT_WRITELOCKED, 0} /*PAGECACHE_LOCK_LEFT_WRITELOCKED*/,
{1,
PAGECACHE_LOCK_WRITE,
PAGECACHE_LOCK_WRITE_TO_READ} /*PAGECACHE_LOCK_READ*/,
{0, PAGECACHE_LOCK_WRITE, 0} /*PAGECACHE_LOCK_WRITE*/,
{0, /*unsupported (we can't write having the block read locked) */
PAGECACHE_LOCK_LEFT_UNLOCKED,
PAGECACHE_LOCK_LEFT_UNLOCKED} /*PAGECACHE_LOCK_READ_UNLOCK*/,
{1,
PAGECACHE_LOCK_LEFT_WRITELOCKED,
PAGECACHE_LOCK_WRITE_UNLOCK } /*PAGECACHE_LOCK_WRITE_UNLOCK*/,
{1,
PAGECACHE_LOCK_LEFT_WRITELOCKED,
PAGECACHE_LOCK_WRITE_TO_READ} /*PAGECACHE_LOCK_WRITE_TO_READ*/
};
/* description of how to change pin before and after write */
struct write_pin_change
{
enum pagecache_page_pin new_pin; /* pin status at the beginning */
enum pagecache_page_pin unlock_pin; /* pin status at the end */
};
static struct write_pin_change write_pin_change_table[]=
{
{PAGECACHE_PIN_LEFT_PINNED,
PAGECACHE_PIN_LEFT_PINNED} /*PAGECACHE_PIN_LEFT_PINNED*/,
{PAGECACHE_PIN,
PAGECACHE_UNPIN} /*PAGECACHE_PIN_LEFT_UNPINNED*/,
{PAGECACHE_PIN,
PAGECACHE_PIN_LEFT_PINNED} /*PAGECACHE_PIN*/,
{PAGECACHE_PIN_LEFT_PINNED,
PAGECACHE_UNPIN} /*PAGECACHE_UNPIN*/
};
my_bool pagecache_write_part(PAGECACHE *pagecache,
PAGECACHE_FILE *file,
pgcache_page_no_t pageno,
uint level,
uchar *buff,
enum pagecache_page_type type,
enum pagecache_page_lock lock,
enum pagecache_page_pin pin,
enum pagecache_write_mode write_mode,
PAGECACHE_BLOCK_LINK **link,
uint offset, uint size,
pagecache_disk_read_validator validator,
uchar* validator_data)
{
PAGECACHE_BLOCK_LINK *block= NULL;
PAGECACHE_BLOCK_LINK *fake_link;
int error= 0;
int need_lock_change= write_lock_change_table[lock].need_lock_change;
DBUG_ENTER("pagecache_write_part");
DBUG_PRINT("enter", ("fd: %u page: %lu level: %u type: %s lock: %s "
"pin: %s mode: %s offset: %u size %u",
(uint) file->file, (ulong) pageno, level,
page_cache_page_type_str[type],
page_cache_page_lock_str[lock],
page_cache_page_pin_str[pin],
page_cache_page_write_mode_str[write_mode],
offset, size));
DBUG_ASSERT(type != PAGECACHE_READ_UNKNOWN_PAGE);
DBUG_ASSERT(lock != PAGECACHE_LOCK_LEFT_READLOCKED);
DBUG_ASSERT(lock != PAGECACHE_LOCK_READ_UNLOCK);
DBUG_ASSERT(offset + size <= pagecache->block_size);
if (!link)
link= &fake_link;
*link= 0;
restart:
#if !defined(DBUG_OFF) && defined(EXTRA_DEBUG)
DBUG_EXECUTE("check_pagecache",
test_key_cache(pagecache, "start of key_cache_write", 1););
#endif
if (pagecache->can_be_used)
{
/* Key cache is used */
int page_st;
pagecache_pthread_mutex_lock(&pagecache->cache_lock);
if (!pagecache->can_be_used)
{
pagecache_pthread_mutex_unlock(&pagecache->cache_lock);
goto no_key_cache;
}
inc_counter_for_resize_op(pagecache);
pagecache->global_cache_w_requests++;
/* See NOTE for pagecache_unlock about registering requests. */
block= find_block(pagecache, file, pageno, level,
test(write_mode != PAGECACHE_WRITE_DONE &&
lock != PAGECACHE_LOCK_LEFT_WRITELOCKED &&
lock != PAGECACHE_LOCK_WRITE_UNLOCK &&
lock != PAGECACHE_LOCK_WRITE_TO_READ),
test((pin == PAGECACHE_PIN_LEFT_UNPINNED) ||
(pin == PAGECACHE_PIN)),
&page_st);
if (!block)
{
DBUG_ASSERT(write_mode != PAGECACHE_WRITE_DONE);
/* It happens only for requests submitted during resize operation */
dec_counter_for_resize_op(pagecache);
pagecache_pthread_mutex_unlock(&pagecache->cache_lock);
/* Write to the disk key cache is in resize at the moment*/
goto no_key_cache;
}
DBUG_ASSERT(block->type == PAGECACHE_EMPTY_PAGE ||
block->type == PAGECACHE_READ_UNKNOWN_PAGE ||
block->type == type ||
(block->type == PAGECACHE_PLAIN_PAGE &&
type == PAGECACHE_LSN_PAGE));
block->type= type;
if (make_lock_and_pin(pagecache, block,
write_lock_change_table[lock].new_lock,
(need_lock_change ?
write_pin_change_table[pin].new_pin :
pin), file))
{
/*
We failed to writelock the block, cache is unlocked, and last write
lock is released, we will try to get the block again.
*/
pagecache_pthread_mutex_unlock(&pagecache->cache_lock);
DBUG_PRINT("info", ("restarting..."));
goto restart;
}
if (write_mode == PAGECACHE_WRITE_DONE)
{
if (!(block->status & PCBLOCK_ERROR))
{
/* Copy data from buff */
if (!(size & 511))
bmove512(block->buffer + offset, buff, size);
else
memcpy(block->buffer + offset, buff, size);
block->status= PCBLOCK_READ;
/*
The validator can change the page content (removing page
protection) so it have to be called
*/
if (validator != NULL &&
(*validator)(block->buffer, validator_data))
block->status|= PCBLOCK_ERROR;
KEYCACHE_DBUG_PRINT("key_cache_insert",
("Page injection"));
#ifdef THREAD
/* Signal that all pending requests for this now can be processed. */
if (block->wqueue[COND_FOR_REQUESTED].last_thread)
wqueue_release_queue(&block->wqueue[COND_FOR_REQUESTED]);
#endif
}
}
else
{
DBUG_ASSERT(validator == 0 && validator_data == 0);
if (! (block->status & PCBLOCK_CHANGED))
link_to_changed_list(pagecache, block);
if (! (block->status & PCBLOCK_ERROR))
{
if (!(size & 511))
bmove512(block->buffer + offset, buff, size);
else
memcpy(block->buffer + offset, buff, size);
block->status|= PCBLOCK_READ;
}
}
if (need_lock_change)
{
/*
We don't set rec_lsn of the block; this is ok as for the
Maria-block-record's pages, we always keep pages pinned here.
*/
if (make_lock_and_pin(pagecache, block,
write_lock_change_table[lock].unlock_lock,
write_pin_change_table[pin].unlock_pin, file))
DBUG_ASSERT(0);
}
/* Unregister the request */
DBUG_ASSERT(block->hash_link->requests > 0);
block->hash_link->requests--;
/* See NOTE for pagecache_unlock about registering requests. */
if (pin == PAGECACHE_PIN_LEFT_UNPINNED || pin == PAGECACHE_UNPIN)
unreg_request(pagecache, block, 1);
else
*link= block;
if (block->status & PCBLOCK_ERROR)
error= 1;
dec_counter_for_resize_op(pagecache);
pagecache_pthread_mutex_unlock(&pagecache->cache_lock);
goto end;
}
no_key_cache:
/* Key cache is not used */
if (write_mode == PAGECACHE_WRITE_DELAY)
{
pagecache->global_cache_w_requests++;
pagecache->global_cache_write++;
if (pagecache_fwrite(pagecache, file, (uchar*) buff, pageno, type,
MYF(MY_NABP | MY_WAIT_IF_FULL)))
error=1;
}
end:
#if !defined(DBUG_OFF) && defined(EXTRA_DEBUG)
DBUG_EXECUTE("exec",
test_key_cache(pagecache, "end of key_cache_write", 1););
#endif
if (block)
PCBLOCK_INFO(block);
else
DBUG_PRINT("info", ("No block"));
DBUG_RETURN(error);
}
/*
Free block: remove reference to it from hash table,
remove it from the chain file of dirty/clean blocks
and add it to the free list.
*/
static void free_block(PAGECACHE *pagecache, PAGECACHE_BLOCK_LINK *block)
{
KEYCACHE_THREAD_TRACE("free block");
KEYCACHE_DBUG_PRINT("free_block",
("block: %u hash_link 0x%lx",
PCBLOCK_NUMBER(pagecache, block),
(long) block->hash_link));
if (block->hash_link)
{
/*
While waiting for readers to finish, new readers might request the
block. But since we set block->status|= PCBLOCK_REASSIGNED, they
will wait on block->wqueue[COND_FOR_SAVED]. They must be signalled
later.
*/
block->status|= PCBLOCK_REASSIGNED;
wait_for_readers(pagecache, block);
unlink_hash(pagecache, block->hash_link);
}
unlink_changed(block);
DBUG_ASSERT(block->wlocks == 0);
DBUG_ASSERT(block->pins == 0);
block->status= 0;
#ifndef DBUG_OFF
block->type= PAGECACHE_EMPTY_PAGE;
#endif
block->rec_lsn= LSN_MAX;
KEYCACHE_THREAD_TRACE("free block");
KEYCACHE_DBUG_PRINT("free_block",
("block is freed"));
unreg_request(pagecache, block, 0);
block->hash_link= NULL;
/* Remove the free block from the LRU ring. */
unlink_block(pagecache, block);
if (block->temperature == PCBLOCK_WARM)
pagecache->warm_blocks--;
block->temperature= PCBLOCK_COLD;
/* Insert the free block in the free list. */
block->next_used= pagecache->free_block_list;
pagecache->free_block_list= block;
/* Keep track of the number of currently unused blocks. */
pagecache->blocks_unused++;
#ifdef THREAD
/* All pending requests for this page must be resubmitted. */
if (block->wqueue[COND_FOR_SAVED].last_thread)
wqueue_release_queue(&block->wqueue[COND_FOR_SAVED]);
#endif
}
static int cmp_sec_link(PAGECACHE_BLOCK_LINK **a, PAGECACHE_BLOCK_LINK **b)
{
return (((*a)->hash_link->pageno < (*b)->hash_link->pageno) ? -1 :
((*a)->hash_link->pageno > (*b)->hash_link->pageno) ? 1 : 0);
}
/*
Flush a portion of changed blocks to disk,
free used blocks if requested
*/
static int flush_cached_blocks(PAGECACHE *pagecache,
PAGECACHE_FILE *file,
PAGECACHE_BLOCK_LINK **cache,
PAGECACHE_BLOCK_LINK **end,
enum flush_type type)
{
int error;
int last_errno= 0;
uint count= (uint) (end-cache);
DBUG_ENTER("flush_cached_blocks");
/* Don't lock the cache during the flush */
pagecache_pthread_mutex_unlock(&pagecache->cache_lock);
/*
As all blocks referred in 'cache' are marked by PCBLOCK_IN_FLUSH
we are guarantied no thread will change them
*/
qsort((uchar*) cache, count, sizeof(*cache), (qsort_cmp) cmp_sec_link);
pagecache_pthread_mutex_lock(&pagecache->cache_lock);
for (; cache != end; cache++)
{
PAGECACHE_BLOCK_LINK *block= *cache;
if (block->pins)
{
KEYCACHE_DBUG_PRINT("flush_cached_blocks",
("block: %u (0x%lx) pinned",
PCBLOCK_NUMBER(pagecache, block), (ulong)block));
DBUG_PRINT("info", ("block: %u (0x%lx) pinned",
PCBLOCK_NUMBER(pagecache, block), (ulong)block));
PCBLOCK_INFO(block);
last_errno= -1;
unreg_request(pagecache, block, 1);
continue;
}
/* if the block is not pinned then it is not write locked */
DBUG_ASSERT(block->wlocks == 0);
DBUG_ASSERT(block->pins == 0);
if (make_lock_and_pin(pagecache, block,
PAGECACHE_LOCK_WRITE, PAGECACHE_PIN, 0))
DBUG_ASSERT(0);
KEYCACHE_DBUG_PRINT("flush_cached_blocks",
("block: %u (0x%lx) to be flushed",
PCBLOCK_NUMBER(pagecache, block), (ulong)block));
DBUG_PRINT("info", ("block: %u (0x%lx) to be flushed",
PCBLOCK_NUMBER(pagecache, block), (ulong)block));
PCBLOCK_INFO(block);
pagecache_pthread_mutex_unlock(&pagecache->cache_lock);
DBUG_PRINT("info", ("block: %u (0x%lx) pins: %u",
PCBLOCK_NUMBER(pagecache, block), (ulong)block,
block->pins));
DBUG_ASSERT(block->pins == 1);
error= pagecache_fwrite(pagecache, file,
block->buffer,
block->hash_link->pageno,
block->type,
MYF(MY_NABP | MY_WAIT_IF_FULL));
pagecache_pthread_mutex_lock(&pagecache->cache_lock);
make_lock_and_pin(pagecache, block,
PAGECACHE_LOCK_WRITE_UNLOCK,
PAGECACHE_UNPIN, 0);
pagecache->global_cache_write++;
if (error)
{
block->status|= PCBLOCK_ERROR;
if (!last_errno)
last_errno= errno ? errno : -1;
}
#ifdef THREAD
/*
Let to proceed for possible waiting requests to write to the block page.
It might happen only during an operation to resize the key cache.
*/
if (block->wqueue[COND_FOR_SAVED].last_thread)
wqueue_release_queue(&block->wqueue[COND_FOR_SAVED]);
#endif
/* type will never be FLUSH_IGNORE_CHANGED here */
if (! (type == FLUSH_KEEP || type == FLUSH_FORCE_WRITE))
{
pagecache->blocks_changed--;
pagecache->global_blocks_changed--;
free_block(pagecache, block);
}
else
{
block->status&= ~PCBLOCK_IN_FLUSH;
link_to_file_list(pagecache, block, file, 1);
unreg_request(pagecache, block, 1);
}
}
DBUG_RETURN(last_errno);
}
/**
@brief flush all key blocks for a file to disk but don't do any mutex locks
@param pagecache pointer to a pagecache data structure
@param file handler for the file to flush to
@param flush_type type of the flush
@note
This function doesn't do any mutex locks because it needs to be called
both from flush_pagecache_blocks and flush_all_key_blocks (the later one
does the mutex lock in the resize_pagecache() function).
@return Operation status
@retval 0 OK
@retval 1 Error
*/
static int flush_pagecache_blocks_int(PAGECACHE *pagecache,
PAGECACHE_FILE *file,
enum flush_type type)
{
PAGECACHE_BLOCK_LINK *cache_buff[FLUSH_CACHE],**cache;
int last_errno= 0;
DBUG_ENTER("flush_pagecache_blocks_int");
DBUG_PRINT("enter",("file: %d blocks_used: %lu blocks_changed: %lu",
file->file, pagecache->blocks_used, pagecache->blocks_changed));
#if !defined(DBUG_OFF) && defined(EXTRA_DEBUG)
DBUG_EXECUTE("check_pagecache",
test_key_cache(pagecache,
"start of flush_pagecache_blocks", 0););
#endif
cache= cache_buff;
if (pagecache->disk_blocks > 0 &&
(!my_disable_flush_pagecache_blocks || type != FLUSH_KEEP))
{
/* Key cache exists and flush is not disabled */
int error= 0;
uint count= 0;
PAGECACHE_BLOCK_LINK **pos, **end;
PAGECACHE_BLOCK_LINK *first_in_switch= NULL;
PAGECACHE_BLOCK_LINK *block, *next;
#if defined(PAGECACHE_DEBUG)
uint cnt= 0;
#endif
uint8 changed_blocks_is_incomplete_incremented= 0;
if (type != FLUSH_IGNORE_CHANGED)
{
/*
Count how many key blocks we have to cache to be able
to flush all dirty pages with minimum seek moves
*/
for (block= pagecache->changed_blocks[FILE_HASH(*file)] ;
block;
block= block->next_changed)
{
if (block->hash_link->file.file == file->file)
{
count++;
KEYCACHE_DBUG_ASSERT(count<= pagecache->blocks_used);
}
}
/* Allocate a new buffer only if its bigger than the one we have */
if (count > FLUSH_CACHE &&
!(cache=
(PAGECACHE_BLOCK_LINK**)
my_malloc(sizeof(PAGECACHE_BLOCK_LINK*)*count, MYF(0))))
{
cache= cache_buff;
count= FLUSH_CACHE;
}
}
/* Retrieve the blocks and write them to a buffer to be flushed */
restart:
end= (pos= cache)+count;
for (block= pagecache->changed_blocks[FILE_HASH(*file)] ;
block;
block= next)
{
#if defined(PAGECACHE_DEBUG)
cnt++;
KEYCACHE_DBUG_ASSERT(cnt <= pagecache->blocks_used);
#endif
next= block->next_changed;
if (block->hash_link->file.file == file->file)
{
/*
Mark the block with BLOCK_IN_FLUSH in order not to let
other threads to use it for new pages and interfere with
our sequence of flushing dirty file pages
*/
block->status|= PCBLOCK_IN_FLUSH;
if (! (block->status & PCBLOCK_IN_SWITCH))
{
/*
We care only for the blocks for which flushing was not
initiated by other threads as a result of page swapping
*/
reg_requests(pagecache, block, 1);
if (type != FLUSH_IGNORE_CHANGED)
{
/* It's not a temporary file */
if (pos == end)
{
/*
This happens only if there is not enough
memory for the big block
*/
if ((error= flush_cached_blocks(pagecache, file, cache,
end,type)))
last_errno=error;
DBUG_PRINT("info", ("restarting..."));
/*
Restart the scan as some other thread might have changed
the changed blocks chain: the blocks that were in switch
state before the flush started have to be excluded
*/
goto restart;
}
*pos++= block;
}
else
{
/* It's a temporary file */
pagecache->blocks_changed--;
pagecache->global_blocks_changed--;
free_block(pagecache, block);
}
}
else
{
/* Link the block into a list of blocks 'in switch' */
unlink_changed(block);
link_changed(block, &first_in_switch);
/*
We have just removed a page from the list of dirty pages
("changed_blocks") though it's still dirty (the flush by another
thread has not yet happened). Checkpoint will miss the page and so
must be blocked until that flush has happened.
Note that if there are two concurrent
flush_pagecache_blocks_int() on this file, then the first one may
move the block into its first_in_switch, and the second one would
just not see the block and wrongly consider its job done.
@todo RECOVERY Maria does protect such flushes with intern_lock,
but Checkpoint does not (Checkpoint makes sure that
changed_blocks_is_incomplete is 0 when it starts, but as
flush_cached_blocks() releases mutex, this may change...
*/
/**
@todo RECOVERY: check all places where we remove a page from the
list of dirty pages
*/
if (unlikely(!changed_blocks_is_incomplete_incremented))
{
changed_blocks_is_incomplete_incremented= 1;
changed_blocks_is_incomplete++;
}
}
}
}
if (pos != cache)
{
if ((error= flush_cached_blocks(pagecache, file, cache, pos, type)))
last_errno= error;
}
/* Wait until list of blocks in switch is empty */
while (first_in_switch)
{
#if defined(PAGECACHE_DEBUG)
cnt= 0;
#endif
block= first_in_switch;
{
#ifdef THREAD
struct st_my_thread_var *thread= my_thread_var;
wqueue_add_to_queue(&block->wqueue[COND_FOR_SAVED], thread);
do
{
KEYCACHE_DBUG_PRINT("flush_pagecache_blocks_int: wait",
("suspend thread %ld", thread->id));
pagecache_pthread_cond_wait(&thread->suspend,
&pagecache->cache_lock);
}
while (thread->next);
#else
KEYCACHE_DBUG_ASSERT(0);
/* No parallel requests in single-threaded case */
#endif
}
#if defined(PAGECACHE_DEBUG)
cnt++;
KEYCACHE_DBUG_ASSERT(cnt <= pagecache->blocks_used);
#endif
}
changed_blocks_is_incomplete-=
changed_blocks_is_incomplete_incremented;
/* The following happens very seldom */
if (! (type == FLUSH_KEEP || type == FLUSH_FORCE_WRITE))
{
#if defined(PAGECACHE_DEBUG)
cnt=0;
#endif
for (block= pagecache->file_blocks[FILE_HASH(*file)] ;
block;
block= next)
{
#if defined(PAGECACHE_DEBUG)
cnt++;
KEYCACHE_DBUG_ASSERT(cnt <= pagecache->blocks_used);
#endif
next= block->next_changed;
if (block->hash_link->file.file == file->file &&
(! (block->status & PCBLOCK_CHANGED)
|| type == FLUSH_IGNORE_CHANGED))
{
reg_requests(pagecache, block, 1);
free_block(pagecache, block);
}
}
}
}
#ifndef DBUG_OFF
DBUG_EXECUTE("check_pagecache",
test_key_cache(pagecache, "end of flush_pagecache_blocks", 0););
#endif
if (cache != cache_buff)
my_free((uchar*) cache, MYF(0));
if (last_errno)
errno=last_errno; /* Return first error */
DBUG_RETURN(last_errno != 0);
}
/*
Flush all blocks for a file to disk
SYNOPSIS
flush_pagecache_blocks()
pagecache pointer to a page cache data structure
file handler for the file to flush to
flush_type type of the flush
RETURN
0 OK
1 error
*/
int flush_pagecache_blocks(PAGECACHE *pagecache,
PAGECACHE_FILE *file, enum flush_type type)
{
int res;
DBUG_ENTER("flush_pagecache_blocks");
DBUG_PRINT("enter", ("pagecache: 0x%lx", (long) pagecache));
if (pagecache->disk_blocks <= 0)
DBUG_RETURN(0);
pagecache_pthread_mutex_lock(&pagecache->cache_lock);
inc_counter_for_resize_op(pagecache);
res= flush_pagecache_blocks_int(pagecache, file, type);
dec_counter_for_resize_op(pagecache);
pagecache_pthread_mutex_unlock(&pagecache->cache_lock);
DBUG_RETURN(res);
}
/*
Reset the counters of a key cache.
SYNOPSIS
reset_pagecache_counters()
name the name of a key cache
pagecache pointer to the pagecache to be reset
DESCRIPTION
This procedure is used to reset the counters of all currently used key
caches, both the default one and the named ones.
RETURN
0 on success (always because it can't fail)
*/
int reset_pagecache_counters(const char *name __attribute__((unused)),
PAGECACHE *pagecache)
{
DBUG_ENTER("reset_pagecache_counters");
if (!pagecache->inited)
{
DBUG_PRINT("info", ("Key cache %s not initialized.", name));
DBUG_RETURN(0);
}
DBUG_PRINT("info", ("Resetting counters for key cache %s.", name));
pagecache->global_blocks_changed= 0; /* Key_blocks_not_flushed */
pagecache->global_cache_r_requests= 0; /* Key_read_requests */
pagecache->global_cache_read= 0; /* Key_reads */
pagecache->global_cache_w_requests= 0; /* Key_write_requests */
pagecache->global_cache_write= 0; /* Key_writes */
DBUG_RETURN(0);
}
/**
@brief Allocates a buffer and stores in it some info about all dirty pages
Does the allocation because the caller cannot know the size itself.
Memory freeing is to be done by the caller (if the "str" member of the
LEX_STRING is not NULL).
Ignores all pages of another type than PAGECACHE_LSN_PAGE, because they
are not interesting for a checkpoint record.
The caller has the intention of doing checkpoints.
@param pagecache pointer to the page cache
@param[out] str pointer to where the allocated buffer, and
its size, will be put
@param[out] min_rec_lsn pointer to where the minimum rec_lsn of all
relevant dirty pages will be put
@return Operation status
@retval 0 OK
@retval 1 Error
*/
my_bool pagecache_collect_changed_blocks_with_lsn(PAGECACHE *pagecache,
LEX_STRING *str,
LSN *min_rec_lsn)
{
my_bool error= 0;
ulong stored_list_size= 0;
uint file_hash;
char *ptr;
LSN minimum_rec_lsn= LSN_MAX;
DBUG_ENTER("pagecache_collect_changed_blocks_with_LSN");
DBUG_ASSERT(NULL == str->str);
/*
We lock the entire cache but will be quick, just reading/writing a few MBs
of memory at most.
*/
pagecache_pthread_mutex_lock(&pagecache->cache_lock);
while (changed_blocks_is_incomplete > 0)
{
/*
Some pages are more recent in memory than on disk (=dirty) and are not
in "changed_blocks" so we cannot know them. Wait.
*/
pagecache_pthread_mutex_unlock(&pagecache->cache_lock);
sleep(1);
pagecache_pthread_mutex_lock(&pagecache->cache_lock);
}
/* Count how many dirty pages are interesting */
for (file_hash= 0; file_hash < PAGECACHE_CHANGED_BLOCKS_HASH; file_hash++)
{
PAGECACHE_BLOCK_LINK *block;
for (block= pagecache->changed_blocks[file_hash] ;
block;
block= block->next_changed)
{
/*
Q: is there something subtle with block->hash_link: can it be NULL?
does it have to be == hash_link->block... ?
*/
DBUG_ASSERT(block->hash_link != NULL);
DBUG_ASSERT(block->status & PCBLOCK_CHANGED);
if (block->type != PAGECACHE_LSN_PAGE)
continue; /* no need to store it */
stored_list_size++;
}
}
compile_time_assert(sizeof(pagecache->blocks) <= 8);
str->length= 8 + /* number of dirty pages */
(4 + /* file */
4 + /* pageno */
LSN_STORE_SIZE /* rec_lsn */
) * stored_list_size;
if (NULL == (str->str= my_malloc(str->length, MYF(MY_WME))))
goto err;
ptr= str->str;
int8store(ptr, (ulonglong)stored_list_size);
ptr+= 8;
if (!stored_list_size)
goto end;
for (file_hash= 0; file_hash < PAGECACHE_CHANGED_BLOCKS_HASH; file_hash++)
{
PAGECACHE_BLOCK_LINK *block;
for (block= pagecache->changed_blocks[file_hash] ;
block;
block= block->next_changed)
{
if (block->type != PAGECACHE_LSN_PAGE)
continue; /* no need to store it in the checkpoint record */
compile_time_assert(sizeof(block->hash_link->file.file) <= 4);
compile_time_assert(sizeof(block->hash_link->pageno) <= 4);
int4store(ptr, block->hash_link->file.file);
ptr+= 4;
int4store(ptr, block->hash_link->pageno);
ptr+= 4;
lsn_store(ptr, block->rec_lsn);
ptr+= LSN_STORE_SIZE;
if (block->rec_lsn != LSN_MAX)
{
DBUG_ASSERT(LSN_VALID(block->rec_lsn));
if (cmp_translog_addr(block->rec_lsn, minimum_rec_lsn) < 0)
minimum_rec_lsn= block->rec_lsn;
} /* otherwise, some trn->rec_lsn should hold the correct info */
}
}
end:
pagecache_pthread_mutex_unlock(&pagecache->cache_lock);
*min_rec_lsn= minimum_rec_lsn;
DBUG_RETURN(error);
err:
error= 1;
goto end;
}
#ifndef DBUG_OFF
/*
Test if disk-cache is ok
*/
static void test_key_cache(PAGECACHE *pagecache __attribute__((unused)),
const char *where __attribute__((unused)),
my_bool lock __attribute__((unused)))
{
/* TODO */
}
#endif
#if defined(PAGECACHE_TIMEOUT)
#define KEYCACHE_DUMP_FILE "pagecache_dump.txt"
#define MAX_QUEUE_LEN 100
static void pagecache_dump(PAGECACHE *pagecache)
{
FILE *pagecache_dump_file=fopen(KEYCACHE_DUMP_FILE, "w");
struct st_my_thread_var *last;
struct st_my_thread_var *thread;
PAGECACHE_BLOCK_LINK *block;
PAGECACHE_HASH_LINK *hash_link;
PAGECACHE_PAGE *page;
uint i;
fprintf(pagecache_dump_file, "thread:%u\n", thread->id);
i=0;
thread=last=waiting_for_hash_link.last_thread;
fprintf(pagecache_dump_file, "queue of threads waiting for hash link\n");
if (thread)
do
{
thread= thread->next;
page= (PAGECACHE_PAGE *) thread->opt_info;
fprintf(pagecache_dump_file,
"thread:%u, (file,pageno)=(%u,%lu)\n",
thread->id,(uint) page->file.file,(ulong) page->pageno);
if (++i == MAX_QUEUE_LEN)
break;
}
while (thread != last);
i=0;
thread=last=waiting_for_block.last_thread;
fprintf(pagecache_dump_file, "queue of threads waiting for block\n");
if (thread)
do
{
thread=thread->next;
hash_link= (PAGECACHE_HASH_LINK *) thread->opt_info;
fprintf(pagecache_dump_file,
"thread:%u hash_link:%u (file,pageno)=(%u,%lu)\n",
thread->id, (uint) PAGECACHE_HASH_LINK_NUMBER(pagecache, hash_link),
(uint) hash_link->file.file,(ulong) hash_link->pageno);
if (++i == MAX_QUEUE_LEN)
break;
}
while (thread != last);
for (i=0 ; i < pagecache->blocks_used ; i++)
{
int j;
block= &pagecache->block_root[i];
hash_link= block->hash_link;
fprintf(pagecache_dump_file,
"block:%u hash_link:%d status:%x #requests=%u waiting_for_readers:%d\n",
i, (int) (hash_link ?
PAGECACHE_HASH_LINK_NUMBER(pagecache, hash_link) :
-1),
block->status, block->requests, block->condvar ? 1 : 0);
for (j=0 ; j < COND_SIZE; j++)
{
PAGECACHE_WQUEUE *wqueue=&block->wqueue[j];
thread= last= wqueue->last_thread;
fprintf(pagecache_dump_file, "queue #%d\n", j);
if (thread)
{
do
{
thread=thread->next;
fprintf(pagecache_dump_file,
"thread:%u\n", thread->id);
if (++i == MAX_QUEUE_LEN)
break;
}
while (thread != last);
}
}
}
fprintf(pagecache_dump_file, "LRU chain:");
block= pagecache= used_last;
if (block)
{
do
{
block= block->next_used;
fprintf(pagecache_dump_file,
"block:%u, ", PCBLOCK_NUMBER(pagecache, block));
}
while (block != pagecache->used_last);
}
fprintf(pagecache_dump_file, "\n");
fclose(pagecache_dump_file);
}
#endif /* defined(PAGECACHE_TIMEOUT) */
#if defined(PAGECACHE_TIMEOUT) && !defined(__WIN__)
static int pagecache_pthread_cond_wait(pthread_cond_t *cond,
pthread_mutex_t *mutex)
{
int rc;
struct timeval now; /* time when we started waiting */
struct timespec timeout; /* timeout value for the wait function */
struct timezone tz;
#if defined(PAGECACHE_DEBUG)
int cnt=0;
#endif
/* Get current time */
gettimeofday(&now, &tz);
/* Prepare timeout value */
timeout.tv_sec= now.tv_sec + PAGECACHE_TIMEOUT;
/*
timeval uses microseconds.
timespec uses nanoseconds.
1 nanosecond = 1000 micro seconds
*/
timeout.tv_nsec= now.tv_usec * 1000;
KEYCACHE_THREAD_TRACE_END("started waiting");
#if defined(PAGECACHE_DEBUG)
cnt++;
if (cnt % 100 == 0)
fprintf(pagecache_debug_log, "waiting...\n");
fflush(pagecache_debug_log);
#endif
rc= pthread_cond_timedwait(cond, mutex, &timeout);
KEYCACHE_THREAD_TRACE_BEGIN("finished waiting");
if (rc == ETIMEDOUT || rc == ETIME)
{
#if defined(PAGECACHE_DEBUG)
fprintf(pagecache_debug_log,"aborted by pagecache timeout\n");
fclose(pagecache_debug_log);
abort();
#endif
pagecache_dump();
}
#if defined(PAGECACHE_DEBUG)
KEYCACHE_DBUG_ASSERT(rc != ETIMEDOUT);
#else
assert(rc != ETIMEDOUT);
#endif
return rc;
}
#else
#if defined(PAGECACHE_DEBUG)
static int pagecache_pthread_cond_wait(pthread_cond_t *cond,
pthread_mutex_t *mutex)
{
int rc;
KEYCACHE_THREAD_TRACE_END("started waiting");
rc= pthread_cond_wait(cond, mutex);
KEYCACHE_THREAD_TRACE_BEGIN("finished waiting");
return rc;
}
#endif
#endif /* defined(PAGECACHE_TIMEOUT) && !defined(__WIN__) */
#if defined(PAGECACHE_DEBUG)
static int ___pagecache_pthread_mutex_lock(pthread_mutex_t *mutex)
{
int rc;
rc= pthread_mutex_lock(mutex);
KEYCACHE_THREAD_TRACE_BEGIN("");
return rc;
}
static void ___pagecache_pthread_mutex_unlock(pthread_mutex_t *mutex)
{
KEYCACHE_THREAD_TRACE_END("");
pthread_mutex_unlock(mutex);
}
static int ___pagecache_pthread_cond_signal(pthread_cond_t *cond)
{
int rc;
KEYCACHE_THREAD_TRACE("signal");
rc= pthread_cond_signal(cond);
return rc;
}
#if defined(PAGECACHE_DEBUG_LOG)
static void pagecache_debug_print(const char * fmt, ...)
{
va_list args;
va_start(args,fmt);
if (pagecache_debug_log)
{
VOID(vfprintf(pagecache_debug_log, fmt, args));
VOID(fputc('\n',pagecache_debug_log));
}
va_end(args);
}
#endif /* defined(PAGECACHE_DEBUG_LOG) */
#if defined(PAGECACHE_DEBUG_LOG)
void pagecache_debug_log_close(void)
{
if (pagecache_debug_log)
fclose(pagecache_debug_log);
}
#endif /* defined(PAGECACHE_DEBUG_LOG) */
#endif /* defined(PAGECACHE_DEBUG) */
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