From 27ae4d128fd870a82b92770e4695c5b57dc8431d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Henrik=20Grubbstr=C3=B6m=20=28Grubba=29?=
<grubba@grubba.org>
Date: Fri, 21 Oct 2016 15:58:57 +0200
Subject: [PATCH] Mapping: Added flag MAPPING_FLAG_NO_SHRINK.
This is a flag that disables shrinking of the mapping_data hashtable
when the number of elements goes below the MIN_LINK_LENGTH threshold.
It is intended to be used by code that has mappings with a high
rotation of content (ie lots of mixed insertions and deletions).
---
src/mapping.c | 20 ++++++++++++--------
src/mapping.h | 1 +
2 files changed, 13 insertions(+), 8 deletions(-)
diff --git a/src/mapping.c b/src/mapping.c
index bf9881baf3..0628dfd839 100644
--- a/src/mapping.c
+++ b/src/mapping.c
@@ -1185,10 +1185,12 @@ PMOD_EXPORT void map_delete_no_free(struct mapping *m,
m->debug_size--;
#endif
- if((md->size < md->hashsize * MIN_LINK_LENGTH) &&
- (md->hashsize > AVG_LINK_LENGTH)) {
- debug_malloc_touch(m);
- rehash(m, MAP_SLOTS(m->data->size));
+ if (!(md->flags & MAPPING_FLAG_NO_SHRINK)) {
+ if((md->size < md->hashsize * MIN_LINK_LENGTH) &&
+ (md->hashsize > AVG_LINK_LENGTH)) {
+ debug_malloc_touch(m);
+ rehash(m, MAP_SLOTS(m->data->size));
+ }
}
#ifdef PIKE_DEBUG
@@ -1260,10 +1262,12 @@ PMOD_EXPORT void check_mapping_for_destruct(struct mapping *m)
md->val_types = val_types;
md->ind_types = ind_types;
- if((MAP_SLOTS(md->size) < md->hashsize * MIN_LINK_LENGTH) &&
- (md->hashsize > AVG_LINK_LENGTH)) {
- debug_malloc_touch(m);
- rehash(m, MAP_SLOTS(md->size));
+ if (!(md->flags & MAPPING_FLAG_NO_SHRINK)) {
+ if((MAP_SLOTS(md->size) < md->hashsize * MIN_LINK_LENGTH) &&
+ (md->hashsize > AVG_LINK_LENGTH)) {
+ debug_malloc_touch(m);
+ rehash(m, MAP_SLOTS(md->size));
+ }
}
#ifdef PIKE_DEBUG
diff --git a/src/mapping.h b/src/mapping.h
index 0444d3d525..763ca2c01c 100644
--- a/src/mapping.h
+++ b/src/mapping.h
@@ -15,6 +15,7 @@
#define MAPPING_WEAK_VALUES 4
#define MAPPING_WEAK 6
#define MAPPING_FLAG_WEAK 6 /* Compat. */
+#define MAPPING_FLAG_NO_SHRINK 0x1000
struct keypair
{
--
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