project-base/server-skynet-source-3rd-jemalloc
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Prefer pages_purge_forced() over memset().

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This has the dual advantages of allowing for sparsely used large
allocations, and relying on the kernel to supply zeroed pages, which
tends to be very fast on modern systems.
This commit is contained in:
Jason Evans 2017-03-09 17:20:00 -08:00
parent 28078274c4
commit 26d23da6cd
2 changed files with 30 additions and 16 deletions
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13
src/extent.c
View File

@ -759,8 +759,11 @@ extent_recycle(tsdn_t *tsdn, arena_t *arena, extent_hooks_t **r_extent_hooks,
if (*zero) {
if (!extent_zeroed_get(extent)) {
memset(extent_addr_get(extent), 0,
extent_usize_get(extent));
if (pages_purge_forced(extent_base_get(extent),
extent_size_get(extent))) {
memset(extent_addr_get(extent), 0,
extent_usize_get(extent));
}
} else if (config_debug) {
size_t i;
size_t *p = (size_t *)(uintptr_t)
@ -971,7 +974,11 @@ extent_grow_retained(tsdn_t *tsdn, arena_t *arena,
extent_interior_register(tsdn, rtree_ctx, extent);
}
if (*zero && !extent_zeroed_get(extent)) {
memset(extent_addr_get(extent), 0, extent_usize_get(extent));
if (pages_purge_forced(extent_base_get(extent),
extent_size_get(extent))) {
memset(extent_addr_get(extent), 0,
extent_usize_get(extent));
}
}
/*
* Increment extent_grow_next, but take care to do so atomically and

33
src/large.c
View File

@ -25,9 +25,13 @@ large_palloc(tsdn_t *tsdn, arena_t *arena, size_t usize, size_t alignment,
return NULL;
}
if (config_fill && unlikely(opt_zero)) {
zero = true;
}
/*
* Copy zero into is_zeroed and pass the copy to extent_alloc(), so that
* it is possible to make correct junk/zero fill decisions below.
* Copy zero into is_zeroed and pass the copy when allocating the
* extent, so that it is possible to make correct junk/zero fill
* decisions below, even if is_zeroed ends up true when zero is false.
*/
is_zeroed = zero;
if (likely(!tsdn_null(tsdn))) {
@ -46,11 +50,8 @@ large_palloc(tsdn_t *tsdn, arena_t *arena, size_t usize, size_t alignment,
prof_idump(tsdn);
}
if (zero || (config_fill && unlikely(opt_zero))) {
if (!is_zeroed) {
memset(extent_addr_get(extent), 0,
extent_usize_get(extent));
}
if (zero) {
assert(is_zeroed);
} else if (config_fill && unlikely(opt_junk_alloc)) {
memset(extent_addr_get(extent), JEMALLOC_ALLOC_JUNK,
extent_usize_get(extent));
@ -144,7 +145,16 @@ large_ralloc_no_move_expand(tsdn_t *tsdn, extent_t *extent, size_t usize,
return true;
}
bool is_zeroed_trail = false;
if (config_fill && unlikely(opt_zero)) {
zero = true;
}
/*
* Copy zero into is_zeroed_trail and pass the copy when allocating the
* extent, so that it is possible to make correct junk/zero fill
* decisions below, even if is_zeroed_trail ends up true when zero is
* false.
*/
bool is_zeroed_trail = zero;
bool commit = true;
extent_t *trail;
bool new_mapping;
@ -174,7 +184,7 @@ large_ralloc_no_move_expand(tsdn_t *tsdn, extent_t *extent, size_t usize,
arena_stats_mapped_add(tsdn, &arena->stats, trailsize);
}
if (zero || (config_fill && unlikely(opt_zero))) {
if (zero) {
if (config_cache_oblivious) {
/*
* Zero the trailing bytes of the original allocation's
@ -191,10 +201,7 @@ large_ralloc_no_move_expand(tsdn_t *tsdn, extent_t *extent, size_t usize,
assert(nzero > 0);
memset(zbase, 0, nzero);
}
if (!is_zeroed_trail) {
memset((void *)((uintptr_t)extent_addr_get(extent) +
oldusize), 0, usize - oldusize);
}
assert(is_zeroed_trail);
} else if (config_fill && unlikely(opt_junk_alloc)) {
memset((void *)((uintptr_t)extent_addr_get(extent) + oldusize),
JEMALLOC_ALLOC_JUNK, usize - oldusize);