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branches/zip: Correct some bugs in the buddy allocator and add debug code.

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buf_buddy_alloc_zip() [UNIV_DEBUG]: Byte-fill the allocated blocks with ~i.

buf_buddy_block_free() [UNIV_DEBUG]: Clear the frame before releasing it
to the buffer pool.

buf_buddy_alloc_from() [UNIV_DEBUG]: Byte-fill the free blocks with j.

buf_buddy_relocate(): Allow the buf_page_hash_get() lookup to fail,
and note the reason.

buf_buddy_free_low(): Correctly compute the address of the combined free block.

buf_page_struct: Clarify the mutex protection rules.  Note that
the pointer zip.data is also protected by buf_pool->mutex.
This commit is contained in:
marko 2006-12-19 12:38:18 +00:00
parent 0a70979184
commit 483cf9bee9
2 changed files with 29 additions and 6 deletions
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25
buf/buf0buddy.c
View file

@ -48,10 +48,18 @@ buf_buddy_alloc_zip(
buf_page_t* buddy = (buf_page_t*)
(((char*) bpage) + (BUF_BUDDY_LOW << i));
ut_d(memset(buddy, i, BUF_BUDDY_LOW << i));
buddy->state = BUF_BLOCK_ZIP_FREE;
UT_LIST_ADD_FIRST(list, buf_pool->zip_free[i], buddy);
}
}
#ifdef UNIV_DEBUG
if (bpage) {
memset(bpage, ~i, BUF_BUDDY_LOW << i);
}
#endif /* UNIV_DEBUG */
return(bpage);
}
@ -76,6 +84,7 @@ buf_buddy_block_free(
((buf_block_t*) bpage)->frame == buf);
ut_a(bpage);
ut_a(buf_page_get_state(bpage) == BUF_BLOCK_MEMORY);
ut_d(memset(buf, 0, UNIV_PAGE_SIZE));
block = (buf_block_t*) bpage;
mutex_enter(&block->mutex);
@ -127,6 +136,7 @@ buf_buddy_alloc_from(
j--;
bpage = (buf_page_t*) ((byte*) buf + offs);
ut_d(memset(bpage, j, BUF_BUDDY_LOW << j));
bpage->state = BUF_BLOCK_ZIP_FREE;
UT_LIST_ADD_FIRST(list, buf_pool->zip_free[j], bpage);
}
@ -311,7 +321,16 @@ buf_buddy_relocate(
+ FIL_PAGE_ARCH_LOG_NO_OR_SPACE_ID),
mach_read_from_4(src
+ FIL_PAGE_OFFSET));
ut_a(bpage);
if (!bpage || bpage->zip.data != src) {
/* The block has probably been freshly
allocated by buf_LRU_get_free_block() but not
added to buf_pool->page_hash yet. Obviously,
it cannot be relocated. */
return(FALSE);
}
mutex = buf_page_get_mutex(bpage);
mutex_enter(mutex);
@ -430,7 +449,7 @@ recombine:
buddy_free:
/* The buddy is free: recombine */
UT_LIST_REMOVE(list, buf_pool->zip_free[i], bpage);
buf = ut_align_down(buf, BUF_BUDDY_LOW << i);
buf = ut_align_down(buf, BUF_BUDDY_LOW << (i + 1));
if (++i < BUF_BUDDY_SIZES) {
@ -476,12 +495,14 @@ buddy_nonfree:
if (buf_buddy_relocate(buddy, buf, i)) {
buf = bpage;
goto buddy_free;
}
}
/* Free the block to the buddy list. */
bpage = buf;
ut_d(memset(bpage, i, BUF_BUDDY_LOW << i));
bpage->state = BUF_BLOCK_ZIP_FREE;
UT_LIST_ADD_FIRST(list, buf_pool->zip_free[i], bpage);
}

10
include/buf0buf.h
View file

@ -900,9 +900,9 @@ for compressed and uncompressed frames */
struct buf_page_struct{
/* None of the following bit-fields must be modified without
holding block->mutex, since they can be stored in the same
machine word. Some of them are additionally protected by
buf_pool->mutex. */
holding block->mutex or buf_pool->zip_mutex, since they can be
stored in the same machine word. Some of them are
additionally protected by buf_pool->mutex. */
unsigned space:32; /* tablespace id */
unsigned offset:32; /* page number */
@ -925,7 +925,9 @@ struct buf_page_struct{
unsigned buf_fix_count:24;/* count of how manyfold this block
is currently bufferfixed */
page_zip_des_t zip; /* compressed page */
page_zip_des_t zip; /* compressed page; zip.data
(but not the data it points to) is
also protected by buf_pool->mutex */
buf_page_t* hash; /* node used in chaining to
buf_pool->page_hash or
buf_pool->zip_hash */