From a9af93fcb9ccf6e120c70e08165f54d5fce44db4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Henrik=20Grubbstr=C3=B6m=20=28Grubba=29?=
<grubba@grubba.org>
Date: Wed, 26 Sep 2012 18:43:06 +0200
Subject: [PATCH] Core: Added a dynamic cache size threshold for
compile_memsearcher().
The internal cache for compile_memsearcher() could grow very large before
the gc would clear some of its entries (each entry has a size of ~16KB).
It now has a dynamic threshold for when it clears the cache on its own.
---
src/pike_search.c | 6 +++++
src/pike_search_engine.c | 50 ++++++++++++++++++++++++++++++++++++++++
2 files changed, 56 insertions(+)
diff --git a/src/pike_search.c b/src/pike_search.c
index ad666796e0..154d83329a 100644
--- a/src/pike_search.c
+++ b/src/pike_search.c
@@ -23,6 +23,12 @@ ptrdiff_t pike_search_struct_offset;
#define OB2MSEARCH(O) ((struct pike_mem_searcher *)((O)->storage+pike_search_struct_offset))
#define THIS_MSEARCH ((struct pike_mem_searcher *)(Pike_fp->current_storage))
+/* NB: We use the least significant bit of memsearch_cache_threshold
+ * to indicate whether we are at MIN_MEMSEARCH_THRESHOLD or not.
+ */
+#define MIN_MEMSEARCH_THRESHOLD 128
+static int memsearch_cache_threshold;
+
static struct mapping *memsearch_cache;
static struct program *pike_search_program;
diff --git a/src/pike_search_engine.c b/src/pike_search_engine.c
index 0cf5668f1b..305f039ef1 100644
--- a/src/pike_search_engine.c
+++ b/src/pike_search_engine.c
@@ -313,6 +313,56 @@ SearchMojt NameN(compile_memsearcher)(NCHAR *needle,
return s->mojt;
}
}
+ /* Paranoia: Junk entry in the mapping. Remove it. */
+ SET_SVAL(stmp, T_STRING, 0, string, hashkey);
+ map_delete(memsearch_cache, &stmp);
+ }
+
+ if (memsearch_cache->data->size >= memsearch_cache_threshold) {
+ /* Perform a gc of all Search objects that only are
+ * referenced from the cache.
+ * Allow the cache to grow to double the size before
+ * the next synchronous gc.
+ */
+ struct keypair *k = NULL;
+ struct mapping_data *md = memsearch_cache->data;
+ int e;
+ int count = 0;
+ /* NB: We inline some stuff from mapping.c here to avoid copying the md.
+ */
+ for (e=0; e < md->hashsize; e++) {
+ struct keypair **prev;
+ for(prev = md->hash + e; (k = *prev);) {
+ count++;
+ if ((TYPEOF(k->val) <= MAX_REF_TYPE) &&
+ (*k->val.u.refs == 1)) {
+ /* map_delete(memsearch_cache, &k->ind); */
+ *prev = k->next;
+ free_svalue(&k->ind);
+ free_svalue(&k->val);
+ mapping_free_keypair(md, k);
+ md->size--;
+ continue;
+ } else if (count < 10) {
+ // locate_references(k->val.u.refs);
+ }
+ prev = &k->next;
+ }
+ }
+ memsearch_cache_threshold = (memsearch_cache->data->size<<1) | 1;
+ if (memsearch_cache_threshold < MIN_MEMSEARCH_THRESHOLD) {
+ memsearch_cache_threshold = MIN_MEMSEARCH_THRESHOLD;
+ }
+ } else if ((memsearch_cache_threshold & 1) &&
+ (memsearch_cache->data->size<<2 < memsearch_cache_threshold)) {
+ /* The real gc() has run and zapped some of our entries.
+ * Assume that all entries left in the cache have more than
+ * one reference.
+ */
+ memsearch_cache_threshold = (memsearch_cache->data->size<<1) | 1;
+ if (memsearch_cache_threshold < MIN_MEMSEARCH_THRESHOLD) {
+ memsearch_cache_threshold = MIN_MEMSEARCH_THRESHOLD;
+ }
}
o=low_clone(pike_search_program);
--
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