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Avoid potential issues on extent zero-out.

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When custom extent_hooks or transparent huge pages are in use, the purging
semantics may change, which means we may not get zeroed pages on repopulating.
Fixing the issue by manually memset for such cases.
This commit is contained in:
Qi Wang 2018-08-10 16:08:50 -07:00 committed by Qi Wang
parent 0ecd5addb1
commit f459454afe
2 changed files with 26 additions and 4 deletions
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5
include/jemalloc/internal/arena_inlines_b.h
View File

@ -8,6 +8,11 @@
#include "jemalloc/internal/sz.h" #include "jemalloc/internal/sz.h"
#include "jemalloc/internal/ticker.h" #include "jemalloc/internal/ticker.h"
JEMALLOC_ALWAYS_INLINE bool
arena_has_default_hooks(arena_t *arena) {
return (extent_hooks_get(arena) == &extent_hooks_default);
}
JEMALLOC_ALWAYS_INLINE arena_t * JEMALLOC_ALWAYS_INLINE arena_t *
arena_choose_maybe_huge(tsd_t *tsd, arena_t *arena, size_t size) { arena_choose_maybe_huge(tsd_t *tsd, arena_t *arena, size_t size) {
if (arena != NULL) { if (arena != NULL) {

25
src/extent.c
View File

@ -1102,6 +1102,17 @@ extent_recycle_split(tsdn_t *tsdn, arena_t *arena,
unreachable(); unreachable();
} }
static bool
extent_need_manual_zero(arena_t *arena) {
/*
* Need to manually zero the extent on repopulating if either; 1) non
* default extent hooks installed (in which case the purge semantics may
* change); or 2) transparent huge pages enabled.
*/
return (!arena_has_default_hooks(arena) ||
(opt_thp == thp_mode_always));
}
/* /*
* Tries to satisfy the given allocation request by reusing one of the extents * Tries to satisfy the given allocation request by reusing one of the extents
* in the given extents_t. * in the given extents_t.
@ -1141,7 +1152,9 @@ extent_recycle(tsdn_t *tsdn, arena_t *arena, extent_hooks_t **r_extent_hooks,
extent, growing_retained); extent, growing_retained);
return NULL; return NULL;
} }
extent_zeroed_set(extent, true); if (!extent_need_manual_zero(arena)) {
extent_zeroed_set(extent, true);
}
} }
if (extent_committed_get(extent)) { if (extent_committed_get(extent)) {
@ -1164,7 +1177,8 @@ extent_recycle(tsdn_t *tsdn, arena_t *arena, extent_hooks_t **r_extent_hooks,
void *addr = extent_base_get(extent); void *addr = extent_base_get(extent);
if (!extent_zeroed_get(extent)) { if (!extent_zeroed_get(extent)) {
size_t size = extent_size_get(extent); size_t size = extent_size_get(extent);
if (pages_purge_forced(addr, size)) { if (extent_need_manual_zero(arena) ||
pages_purge_forced(addr, size)) {
memset(addr, 0, size); memset(addr, 0, size);
} }
} else if (config_debug) { } else if (config_debug) {
@ -1391,7 +1405,9 @@ extent_grow_retained(tsdn_t *tsdn, arena_t *arena,
&arena->extents_retained, extent, true); &arena->extents_retained, extent, true);
goto label_err; goto label_err;
} }
extent_zeroed_set(extent, true); if (!extent_need_manual_zero(arena)) {
extent_zeroed_set(extent, true);
}
} }
/* /*
@ -1425,7 +1441,8 @@ extent_grow_retained(tsdn_t *tsdn, arena_t *arena,
if (*zero && !extent_zeroed_get(extent)) { if (*zero && !extent_zeroed_get(extent)) {
void *addr = extent_base_get(extent); void *addr = extent_base_get(extent);
size_t size = extent_size_get(extent); size_t size = extent_size_get(extent);
if (pages_purge_forced(addr, size)) { if (extent_need_manual_zero(arena) ||
pages_purge_forced(addr, size)) {
memset(addr, 0, size); memset(addr, 0, size);
} }
} }