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Implement guard pages.

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Adding guarded extents, which are regular extents surrounded by guard pages
(mprotected).  To reduce syscalls, small guarded extents are cached as a
separate eset in ecache, and decay through the dirty / muzzy / retained pipeline
as usual.
This commit is contained in:
Qi Wang
2021-04-26 14:22:25 -07:00
committed by Qi Wang
parent 7bb05e04be
commit deb8e62a83
41 changed files with 920 additions and 251 deletions
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27
src/pa.c
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@@ -1,6 +1,7 @@
#include "jemalloc/internal/jemalloc_preamble.h"
#include "jemalloc/internal/jemalloc_internal_includes.h"
#include "jemalloc/internal/guard.h"
#include "jemalloc/internal/hpa.h"
static void
@@ -118,15 +119,17 @@ pa_get_pai(pa_shard_t *shard, edata_t *edata) {
edata_t *
pa_alloc(tsdn_t *tsdn, pa_shard_t *shard, size_t size, size_t alignment,
bool slab, szind_t szind, bool zero, bool *deferred_work_generated) {
bool slab, szind_t szind, bool zero, bool guarded,
bool *deferred_work_generated) {
witness_assert_depth_to_rank(tsdn_witness_tsdp_get(tsdn),
WITNESS_RANK_CORE, 0);
assert(!guarded || alignment <= PAGE);
edata_t *edata = NULL;
*deferred_work_generated = false;
if (pa_shard_uses_hpa(shard)) {
if (!guarded && pa_shard_uses_hpa(shard)) {
edata = pai_alloc(tsdn, &shard->hpa_sec.pai, size, alignment,
zero, deferred_work_generated);
zero, /* guarded */ false, deferred_work_generated);
}
/*
* Fall back to the PAC if the HPA is off or couldn't serve the given
@@ -134,10 +137,10 @@ pa_alloc(tsdn_t *tsdn, pa_shard_t *shard, size_t size, size_t alignment,
*/
if (edata == NULL) {
edata = pai_alloc(tsdn, &shard->pac.pai, size, alignment, zero,
deferred_work_generated);
guarded, deferred_work_generated);
}
if (edata != NULL) {
assert(edata_size_get(edata) == size);
pa_nactive_add(shard, size >> LG_PAGE);
emap_remap(tsdn, shard->emap, edata, szind, slab);
edata_szind_set(edata, szind);
@@ -145,8 +148,6 @@ pa_alloc(tsdn_t *tsdn, pa_shard_t *shard, size_t size, size_t alignment,
if (slab && (size > 2 * PAGE)) {
emap_register_interior(tsdn, shard->emap, edata, szind);
}
}
if (edata != NULL) {
assert(edata_arena_ind_get(edata) == shard->ind);
}
return edata;
@@ -158,7 +159,9 @@ pa_expand(tsdn_t *tsdn, pa_shard_t *shard, edata_t *edata, size_t old_size,
assert(new_size > old_size);
assert(edata_size_get(edata) == old_size);
assert((new_size & PAGE_MASK) == 0);
if (edata_guarded_get(edata)) {
return true;
}
size_t expand_amount = new_size - old_size;
pai_t *pai = pa_get_pai(shard, edata);
@@ -181,6 +184,9 @@ pa_shrink(tsdn_t *tsdn, pa_shard_t *shard, edata_t *edata, size_t old_size,
assert(new_size < old_size);
assert(edata_size_get(edata) == old_size);
assert((new_size & PAGE_MASK) == 0);
if (edata_guarded_get(edata)) {
return true;
}
size_t shrink_amount = old_size - new_size;
pai_t *pai = pa_get_pai(shard, edata);
@@ -202,7 +208,10 @@ pa_dalloc(tsdn_t *tsdn, pa_shard_t *shard, edata_t *edata,
emap_remap(tsdn, shard->emap, edata, SC_NSIZES, /* slab */ false);
if (edata_slab_get(edata)) {
emap_deregister_interior(tsdn, shard->emap, edata);
edata_slab_set(edata, false);
/*
* The slab state of the extent isn't cleared. It may be used
* by the pai implementation, e.g. to make caching decisions.
*/
}
edata_addr_set(edata, edata_base_get(edata));
edata_szind_set(edata, SC_NSIZES);