project-base/server-skynet-source-3rd-jemalloc
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Simplify small object allocation/deallocation.

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Use chained run free lists instead of bitmaps to track free objects
within small runs.

Remove reference counting for small object run pages.
This commit is contained in:
Jason Evans
2010-03-13 13:41:58 -08:00
parent 3fa9a2fad8
commit 1e0a636c11
2 changed files with 135 additions and 343 deletions
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41
jemalloc/include/jemalloc/internal/arena.h
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@@ -18,11 +18,7 @@
#ifdef JEMALLOC_TINY
/* Smallest size class to support. */
# ifdef JEMALLOC_TCACHE
# define LG_TINY_MIN LG_SIZEOF_PTR
# else
# define LG_TINY_MIN 1
# endif
# define LG_TINY_MIN LG_SIZEOF_PTR
#endif
/*
@@ -77,12 +73,6 @@
#define RUN_MAX_OVRHD 0x0000003dU
#define RUN_MAX_OVRHD_RELAX 0x00001800U
/* Put a cap on small object run size. This overrides RUN_MAX_OVRHD. */
#define RUN_MAX_SMALL \
(arena_maxclass <= (1U << (CHUNK_MAP_LG_PG_RANGE + PAGE_SHIFT)) \
? arena_maxclass : (1U << (CHUNK_MAP_LG_PG_RANGE + \
PAGE_SHIFT)))
/*
* The minimum ratio of active:dirty pages per arena is computed as:
*
@@ -130,7 +120,6 @@ struct arena_chunk_map_s {
* Small/medium: Don't care.
* Large: Run size for first page, unset for trailing pages.
* - : Unused.
* c : refcount (could overflow for PAGE_SIZE >= 128 KiB)
* d : dirty?
* z : zeroed?
* l : large?
@@ -150,9 +139,9 @@ struct arena_chunk_map_s {
* ssssssss ssssssss ssss---- -----z--
*
* Small/medium:
* pppppppp ppppcccc cccccccc cccc---a
* pppppppp ppppcccc cccccccc cccc---a
* pppppppp ppppcccc cccccccc cccc---a
* pppppppp pppppppp pppp---- -------a
* pppppppp pppppppp pppp---- -------a
* pppppppp pppppppp pppp---- -------a
*
* Large:
* ssssssss ssssssss ssss---- ------la
@@ -160,12 +149,9 @@ struct arena_chunk_map_s {
* -------- -------- -------- ------la
*/
size_t bits;
#define CHUNK_MAP_PG_MASK ((size_t)0xfff00000U)
#define CHUNK_MAP_PG_SHIFT 20
#define CHUNK_MAP_LG_PG_RANGE 12
#define CHUNK_MAP_RC_MASK ((size_t)0xffff0U)
#define CHUNK_MAP_RC_ONE ((size_t)0x00010U)
#define CHUNK_MAP_PG_MASK ((size_t)0xfffff000U)
#define CHUNK_MAP_PG_SHIFT 12
#define CHUNK_MAP_LG_PG_RANGE 20
#define CHUNK_MAP_FLAGS_MASK ((size_t)0xfU)
#define CHUNK_MAP_DIRTY ((size_t)0x8U)
@@ -209,14 +195,14 @@ struct arena_run_s {
/* Bin this run is associated with. */
arena_bin_t *bin;
/* Index of first element that might have a free region. */
unsigned regs_minelm;
/* Stack of available freed regions, or NULL. */
void *avail;
/* Next region that has never been allocated, or run boundary. */
void *next;
/* Number of free regions in run. */
unsigned nfree;
/* Bitmask of in-use regions (0: in use, 1: free). */
unsigned regs_mask[1]; /* Dynamically sized. */
};
struct arena_bin_s {
@@ -244,9 +230,6 @@ struct arena_bin_s {
/* Total number of regions in a run for this bin's size class. */
uint32_t nregs;
/* Number of elements in a run's regs_mask for this bin's size class. */
uint32_t regs_mask_nelms;
#ifdef JEMALLOC_PROF
/*
* Offset of first (prof_cnt_t *) in a run header for this bin's size