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-rw-r--r--src/extent.c76
-rw-r--r--src/extent_dss.c5
2 files changed, 62 insertions, 19 deletions
diff --git a/src/extent.c b/src/extent.c
index e83d9c8c..416d68fb 100644
--- a/src/extent.c
+++ b/src/extent.c
@@ -50,20 +50,16 @@ static bool extent_purge_forced_default(extent_hooks_t *extent_hooks,
static bool extent_purge_forced_impl(tsdn_t *tsdn, arena_t *arena,
extent_hooks_t **r_extent_hooks, extent_t *extent, size_t offset,
size_t length, bool growing_retained);
-#ifdef JEMALLOC_MAPS_COALESCE
static bool extent_split_default(extent_hooks_t *extent_hooks, void *addr,
size_t size, size_t size_a, size_t size_b, bool committed,
unsigned arena_ind);
-#endif
static extent_t *extent_split_impl(tsdn_t *tsdn, arena_t *arena,
extent_hooks_t **r_extent_hooks, extent_t *extent, size_t size_a,
szind_t szind_a, bool slab_a, size_t size_b, szind_t szind_b, bool slab_b,
bool growing_retained);
-#ifdef JEMALLOC_MAPS_COALESCE
static bool extent_merge_default(extent_hooks_t *extent_hooks, void *addr_a,
size_t size_a, void *addr_b, size_t size_b, bool committed,
unsigned arena_ind);
-#endif
static bool extent_merge_impl(tsdn_t *tsdn, arena_t *arena,
extent_hooks_t **r_extent_hooks, extent_t *a, extent_t *b,
bool growing_retained);
@@ -88,11 +84,9 @@ const extent_hooks_t extent_hooks_default = {
,
NULL
#endif
-#ifdef JEMALLOC_MAPS_COALESCE
,
extent_split_default,
extent_merge_default
-#endif
};
/* Used exclusively for gdump triggering. */
@@ -1323,7 +1317,7 @@ extent_grow_retained(tsdn_t *tsdn, arena_t *arena,
extent_init(extent, arena, ptr, alloc_size, false, SC_NSIZES,
arena_extent_sn_next(arena), extent_state_active, zeroed,
- committed, true);
+ committed, true, EXTENT_IS_HEAD);
if (ptr == NULL) {
extent_dalloc(tsdn, arena, extent);
goto label_err;
@@ -1495,7 +1489,7 @@ extent_alloc_wrapper_hard(tsdn_t *tsdn, arena_t *arena,
}
extent_init(extent, arena, addr, esize, slab, szind,
arena_extent_sn_next(arena), extent_state_active, *zero, *commit,
- true);
+ true, EXTENT_NOT_HEAD);
if (pad != 0) {
extent_addr_randomize(tsdn, extent, alignment);
}
@@ -2045,13 +2039,20 @@ extent_purge_forced_wrapper(tsdn_t *tsdn, arena_t *arena,
offset, length, false);
}
-#ifdef JEMALLOC_MAPS_COALESCE
static bool
extent_split_default(extent_hooks_t *extent_hooks, void *addr, size_t size,
size_t size_a, size_t size_b, bool committed, unsigned arena_ind) {
- return !maps_coalesce;
+ if (!maps_coalesce) {
+ /*
+ * Without retain, only whole regions can be purged (required by
+ * MEM_RELEASE on Windows) -- therefore disallow splitting. See
+ * comments in extent_head_no_merge().
+ */
+ return !opt_retain;
+ }
+
+ return false;
}
-#endif
/*
* Accepts the extent to split, and the characteristics of each side of the
@@ -2083,7 +2084,8 @@ extent_split_impl(tsdn_t *tsdn, arena_t *arena,
extent_init(trail, arena, (void *)((uintptr_t)extent_base_get(extent) +
size_a), size_b, slab_b, szind_b, extent_sn_get(extent),
extent_state_get(extent), extent_zeroed_get(extent),
- extent_committed_get(extent), extent_dumpable_get(extent));
+ extent_committed_get(extent), extent_dumpable_get(extent),
+ EXTENT_NOT_HEAD);
rtree_ctx_t rtree_ctx_fallback;
rtree_ctx_t *rtree_ctx = tsdn_rtree_ctx(tsdn, &rtree_ctx_fallback);
@@ -2094,7 +2096,8 @@ extent_split_impl(tsdn_t *tsdn, arena_t *arena,
extent_init(&lead, arena, extent_addr_get(extent), size_a,
slab_a, szind_a, extent_sn_get(extent),
extent_state_get(extent), extent_zeroed_get(extent),
- extent_committed_get(extent), extent_dumpable_get(extent));
+ extent_committed_get(extent), extent_dumpable_get(extent),
+ EXTENT_NOT_HEAD);
extent_rtree_leaf_elms_lookup(tsdn, rtree_ctx, &lead, false,
true, &lead_elm_a, &lead_elm_b);
@@ -2152,7 +2155,7 @@ extent_split_wrapper(tsdn_t *tsdn, arena_t *arena,
static bool
extent_merge_default_impl(void *addr_a, void *addr_b) {
- if (!maps_coalesce) {
+ if (!maps_coalesce && !opt_retain) {
return true;
}
if (have_dss && !extent_dss_mergeable(addr_a, addr_b)) {
@@ -2162,13 +2165,51 @@ extent_merge_default_impl(void *addr_a, void *addr_b) {
return false;
}
-#ifdef JEMALLOC_MAPS_COALESCE
+/*
+ * Returns true if the given extents can't be merged because of their head bit
+ * settings. Assumes the second extent has the higher address.
+ */
+static bool
+extent_head_no_merge(extent_t *a, extent_t *b) {
+ assert(extent_base_get(a) < extent_base_get(b));
+ /*
+ * When coalesce is not always allowed (Windows), only merge extents
+ * from the same VirtualAlloc region under opt.retain (in which case
+ * MEM_DECOMMIT is utilized for purging).
+ */
+ if (maps_coalesce) {
+ return false;
+ }
+ if (!opt_retain) {
+ return true;
+ }
+ /* If b is a head extent, disallow the cross-region merge. */
+ if (extent_is_head_get(b)) {
+ /*
+ * Additionally, sn should not overflow with retain; sanity
+ * check that different regions have unique sn.
+ */
+ assert(extent_sn_comp(a, b) != 0);
+ return true;
+ }
+ assert(extent_sn_comp(a, b) == 0);
+
+ return false;
+}
+
static bool
extent_merge_default(extent_hooks_t *extent_hooks, void *addr_a, size_t size_a,
void *addr_b, size_t size_b, bool committed, unsigned arena_ind) {
+ if (!maps_coalesce) {
+ tsdn_t *tsdn = tsdn_fetch();
+ extent_t *a = iealloc(tsdn, addr_a);
+ extent_t *b = iealloc(tsdn, addr_b);
+ if (extent_head_no_merge(a, b)) {
+ return true;
+ }
+ }
return extent_merge_default_impl(addr_a, addr_b);
}
-#endif
static bool
extent_merge_impl(tsdn_t *tsdn, arena_t *arena,
@@ -2176,10 +2217,11 @@ extent_merge_impl(tsdn_t *tsdn, arena_t *arena,
bool growing_retained) {
witness_assert_depth_to_rank(tsdn_witness_tsdp_get(tsdn),
WITNESS_RANK_CORE, growing_retained ? 1 : 0);
+ assert(extent_base_get(a) < extent_base_get(b));
extent_hooks_assure_initialized(arena, r_extent_hooks);
- if ((*r_extent_hooks)->merge == NULL) {
+ if ((*r_extent_hooks)->merge == NULL || extent_head_no_merge(a, b)) {
return true;
}
diff --git a/src/extent_dss.c b/src/extent_dss.c
index 69a7bee8..85817891 100644
--- a/src/extent_dss.c
+++ b/src/extent_dss.c
@@ -156,7 +156,8 @@ extent_alloc_dss(tsdn_t *tsdn, arena_t *arena, void *new_addr, size_t size,
extent_init(gap, arena, gap_addr_page,
gap_size_page, false, SC_NSIZES,
arena_extent_sn_next(arena),
- extent_state_active, false, true, true);
+ extent_state_active, false, true, true,
+ EXTENT_NOT_HEAD);
}
/*
* Compute the address just past the end of the desired
@@ -200,7 +201,7 @@ extent_alloc_dss(tsdn_t *tsdn, arena_t *arena, void *new_addr, size_t size,
extent_init(&extent, arena, ret, size,
size, false, SC_NSIZES,
extent_state_active, false, true,
- true);
+ true, EXTENT_NOT_HEAD);
if (extent_purge_forced_wrapper(tsdn,
arena, &extent_hooks, &extent, 0,
size)) {