romenskiy2012/jemalloc
1
0
Fork 0
mirror of https://github.com/jemalloc/jemalloc.git synced 2026-04-14 22:51:50 +03:00
Code Issues Projects Releases Packages Wiki Activity

Prepare tcache for size to grow by PAGE over GROUP*PAGE

Browse source 
To prepare for the upcoming changes where size class grows by PAGE when
larger than NGROUP * PAGE, disable the tcache when it is larger than 2 *
NGROUP * PAGE. The threshold for tcache is set higher to prevent perf
regression as much as possible while usizes between NGROUP * PAGE and 2 *
NGROUP * PAGE happen to grow by PAGE.
This commit is contained in:
Guangli Dai 2025-01-31 14:07:05 -08:00
parent eac4163a95
commit 205ba7b223
3 changed files with 26 additions and 1 deletions
Download patch file Download diff file Expand all files Collapse all files

18
include/jemalloc/internal/sc.h
View file

@ -286,6 +286,24 @@
# endif
#endif
/*
* When config_limit_usize_gap is enabled, the gaps between two contiguous
* size classes should not exceed PAGE. This means there should be no concept
* of size classes for sizes > SC_SMALL_MAXCLASS (or >= SC_LARGE_MINCLASS).
* However, between SC_LARGE_MINCLASS (SC_NGROUP * PAGE) and
* 2 * SC_NGROUP * PAGE, the size class also happens to be aligned with PAGE.
* Since tcache relies on size classes to work and it greatly increases the
* perf of allocs & deallocs, we extend the existence of size class to
* 2 * SC_NGROUP * PAGE ONLY for the tcache module. This means for all other
* modules, there is no size class for sizes >= SC_LARGE_MINCLASS. Yet for
* tcache, the threshold is moved up to 2 * SC_NGROUP * PAGE, which is
* USIZE_GROW_SLOW_THRESHOLD defined below. With the default SC_NGROUP being
* 2, and PAGE being 4KB, the threshold for tcache (USIZE_GROW_SLOW_THRESHOLD)
* is 32KB.
*/
#define LG_USIZE_GROW_SLOW_THRESHOLD (SC_LG_NGROUP + LG_PAGE + 1)
#define USIZE_GROW_SLOW_THRESHOLD (1U << LG_USIZE_GROW_SLOW_THRESHOLD)
#define SC_SLAB_MAXREGS (1U << SC_LG_SLAB_MAXREGS)
typedef struct sc_s sc_t;

6
include/jemalloc/internal/tcache_types.h
View file

@ -19,7 +19,11 @@ typedef struct tcaches_s tcaches_t;
/* NOLINTNEXTLINE(performance-no-int-to-ptr) */
#define TCACHES_ELM_NEED_REINIT ((tcache_t *)(uintptr_t)1)
#define TCACHE_LG_MAXCLASS_LIMIT 23 /* tcache_max = 8M */
#ifdef LIMIT_USIZE_GAP
#define TCACHE_LG_MAXCLASS_LIMIT LG_USIZE_GROW_SLOW_THRESHOLD
#else
#define TCACHE_LG_MAXCLASS_LIMIT 23 /* tcache_max = 8M */
#endif
#define TCACHE_MAXCLASS_LIMIT ((size_t)1 << TCACHE_LG_MAXCLASS_LIMIT)
#define TCACHE_NBINS_MAX (SC_NBINS + SC_NGROUP * \
(TCACHE_LG_MAXCLASS_LIMIT - SC_LG_LARGE_MINCLASS) + 1)

3
src/jemalloc.c
View file

@ -2201,6 +2201,9 @@ static bool
malloc_init_hard(void) {
tsd_t *tsd;
if (config_limit_usize_gap) {
assert(TCACHE_MAXCLASS_LIMIT <= USIZE_GROW_SLOW_THRESHOLD);
}
#if defined(_WIN32) && _WIN32_WINNT < 0x0600
_init_init_lock();
#endif