MINOR: pools: add a new debugging flag POOL_DBG_COLD_FIRST
When enabling pools integrity checks, we usually prefer to allocate cold
objects first in order to maximize the time the objects spend in the
cache. In order to make this configurable at runtime, let's introduce
a new debugging flag to control this allocation order. It is currently
preset by the DEBUG_POOL_INTEGRITY build-time setting.
diff --git a/include/haproxy/pool-t.h b/include/haproxy/pool-t.h
index 37980c6..a1a9f65 100644
--- a/include/haproxy/pool-t.h
+++ b/include/haproxy/pool-t.h
@@ -43,6 +43,7 @@
/* pool debugging flags */
#define POOL_DBG_FAIL_ALLOC 0x00000001 // randomly fail memory allocations
#define POOL_DBG_DONT_MERGE 0x00000002 // do not merge same-size pools
+#define POOL_DBG_COLD_FIRST 0x00000004 // pick cold objects first
/* This is the head of a thread-local cache */
diff --git a/include/haproxy/pool.h b/include/haproxy/pool.h
index 541e0d9..1d22424 100644
--- a/include/haproxy/pool.h
+++ b/include/haproxy/pool.h
@@ -275,16 +275,18 @@
return NULL;
}
+ if (unlikely(pool_debugging & POOL_DBG_COLD_FIRST)) {
+ /* allocate oldest objects first so as to keep them as long as possible
+ * in the cache before being reused and maximizing the chance to detect
+ * an overwrite.
+ */
+ item = LIST_PREV(&ph->list, typeof(item), by_pool);
+ } else {
+ /* allocate hottest objects first */
+ item = LIST_NEXT(&ph->list, typeof(item), by_pool);
+ }
#if defined(DEBUG_POOL_INTEGRITY)
- /* allocate oldest objects first so as to keep them as long as possible
- * in the cache before being reused and maximizing the chance to detect
- * an overwrite.
- */
- item = LIST_PREV(&ph->list, typeof(item), by_pool);
pool_check_pattern(ph, item, pool->size);
-#else
- /* allocate hottest objects first */
- item = LIST_NEXT(&ph->list, typeof(item), by_pool);
#endif
BUG_ON(&item->by_pool == &ph->list);
LIST_DELETE(&item->by_pool);
diff --git a/src/pool.c b/src/pool.c
index 7f9c3df..87ab4b6 100644
--- a/src/pool.c
+++ b/src/pool.c
@@ -44,6 +44,9 @@
#ifdef DEBUG_DONT_SHARE_POOLS
POOL_DBG_DONT_MERGE |
#endif
+#ifdef DEBUG_POOL_INTEGRITY
+ POOL_DBG_COLD_FIRST |
+#endif
0;
static int mem_fail_rate __read_mostly = 0;