mariadb/include/buf0buddy.h
marko d56453be8e branches/zip: buf_LRU_search_and_free_block(): Avoid freeing compressed-only
pages when they do not occupy too much of the buffer pool.

buf0buddy.c, buf0buddy.h: Export buf_buddy_n_frames and buf_buddy_min_n_frames.
2007-02-16 09:22:50 +00:00

62 lines
1.9 KiB
C

/******************************************************
Binary buddy allocator for compressed pages
(c) 2006 Innobase Oy
Created December 2006 by Marko Makela
*******************************************************/
#ifndef buf0buddy_h
#define buf0buddy_h
#ifdef UNIV_MATERIALIZE
# undef UNIV_INLINE
# define UNIV_INLINE
#endif
#include "univ.i"
#include "buf0types.h"
/**************************************************************************
Allocate a block. The thread calling this function must hold
buf_pool->mutex and must not hold buf_pool->zip_mutex or any block->mutex.
The buf_pool->mutex may only be released and reacquired if
lru == BUF_BUDDY_USE_LRU. */
UNIV_INLINE
void*
buf_buddy_alloc(
/*============*/
/* out: allocated block,
possibly NULL if lru == NULL */
ulint size, /* in: block size, up to UNIV_PAGE_SIZE */
ibool* lru) /* in: pointer to a variable that will be assigned
TRUE if storage was allocated from the LRU list
and buf_pool->mutex was temporarily released,
or NULL if the LRU list should not be used */
__attribute__((malloc));
/**************************************************************************
Release a block. */
UNIV_INLINE
void
buf_buddy_free(
/*===========*/
void* buf, /* in: block to be freed, must not be
pointed to by the buffer pool */
ulint size) /* in: block size, up to UNIV_PAGE_SIZE */
__attribute__((nonnull));
/** Number of frames allocated from the buffer pool to the buddy system.
Protected by buf_pool->mutex. */
extern ulint buf_buddy_n_frames;
/** Preferred minimum number of frames allocated from the buffer pool
to the buddy system. When this number is exceeded, the buddy allocator
will not try to free clean compressed-only pages in order to satisfy
an allocation request. Protected by buf_pool->mutex. */
extern ulint buf_buddy_min_n_frames;
#ifndef UNIV_NONINL
# include "buf0buddy.ic"
#endif
#endif /* buf0buddy_h */