From: Willy Tarreau <w@1wt.eu>
Date: Mon, 21 Feb 2022 16:16:22 +0000 (+0100)
Subject: MINOR: pools: switch the fail-alloc test to runtime only
X-Git-Tag: v2.6-dev2~83
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=8d0273ed88ceac6d02bc30234d07dd77dee89b11;p=thirdparty%2Fhaproxy.git

MINOR: pools: switch the fail-alloc test to runtime only

The fail-alloc test used to be enabled/disabled at build time using
the DEBUG_FAIL_ALLOC macro, but it happens that the cost of the test
is quite cheap and that it can be enabled as one of the pool_debugging
options.

This patch thus introduces the first POOL_DBG_FAIL_ALLOC option, whose
default value depends on DEBUG_FAIL_ALLOC. The mem_should_fail() function
is now always built, but it was made static since it's never used outside.
---

diff --git a/include/haproxy/pool-t.h b/include/haproxy/pool-t.h
index a9234dd3c6..8180bfb158 100644
--- a/include/haproxy/pool-t.h
+++ b/include/haproxy/pool-t.h
@@ -40,6 +40,9 @@
 #define POOL_F_MUST_ZERO    0x00000002  // zero the returned area
 #define POOL_F_NO_FAIL      0x00000004  // do not randomly fail
 
+/* pool debugging flags */
+#define POOL_DBG_FAIL_ALLOC 0x00000001  // randomly fail memory allocations
+
 
 /* This is the head of a thread-local cache */
 struct pool_cache_head {
diff --git a/include/haproxy/pool.h b/include/haproxy/pool.h
index 2c3c7db550..541e0d96bf 100644
--- a/include/haproxy/pool.h
+++ b/include/haproxy/pool.h
@@ -129,7 +129,6 @@ struct pool_head *create_pool(char *name, unsigned int size, unsigned int flags)
 void create_pool_callback(struct pool_head **ptr, char *name, unsigned int size);
 void *pool_destroy(struct pool_head *pool);
 void pool_destroy_all(void);
-int mem_should_fail(const struct pool_head *pool);
 void *__pool_alloc(struct pool_head *pool, unsigned int flags);
 void __pool_free(struct pool_head *pool, void *ptr);
 
diff --git a/src/pool.c b/src/pool.c
index 8462accd03..3c85b08ee6 100644
--- a/src/pool.c
+++ b/src/pool.c
@@ -37,12 +37,13 @@ THREAD_LOCAL size_t pool_cache_count = 0;                /* #cache objects   */
 
 static struct list pools __read_mostly = LIST_HEAD_INIT(pools);
 int mem_poison_byte __read_mostly = -1;
-uint pool_debugging __read_mostly = 0;                   /* set of POOL_DBG_* flags */
-
+uint pool_debugging __read_mostly =               /* set of POOL_DBG_* flags */
 #ifdef DEBUG_FAIL_ALLOC
-static int mem_fail_rate __read_mostly = 0;
+	POOL_DBG_FAIL_ALLOC |
 #endif
+	0;
 
+static int mem_fail_rate __read_mostly = 0;
 static int using_default_allocator __read_mostly = 1;
 static int(*my_mallctl)(const char *, void *, size_t *, void *, size_t) = NULL;
 
@@ -151,6 +152,19 @@ static int is_trim_enabled(void)
 	return using_default_allocator;
 }
 
+static int mem_should_fail(const struct pool_head *pool)
+{
+	int ret = 0;
+
+	if (mem_fail_rate > 0 && !(global.mode & MODE_STARTING)) {
+		if (mem_fail_rate > statistical_prng_range(100))
+			ret = 1;
+		else
+			ret = 0;
+	}
+	return ret;
+}
+
 /* Try to find an existing shared pool with the same characteristics and
  * returns it, otherwise creates this one. NULL is returned if no memory
  * is available for a new creation. Two flags are supported :
@@ -619,10 +633,9 @@ void *__pool_alloc(struct pool_head *pool, unsigned int flags)
 	void *p = NULL;
 	void *caller = NULL;
 
-#ifdef DEBUG_FAIL_ALLOC
-	if (unlikely(!(flags & POOL_F_NO_FAIL) && mem_should_fail(pool)))
-		return NULL;
-#endif
+	if (unlikely(pool_debugging & POOL_DBG_FAIL_ALLOC))
+		if (!(flags & POOL_F_NO_FAIL) && mem_should_fail(pool))
+			return NULL;
 
 #if defined(DEBUG_POOL_TRACING)
 	caller = __builtin_return_address(0);
@@ -898,21 +911,6 @@ static struct cli_kw_list cli_kws = {{ },{
 
 INITCALL1(STG_REGISTER, cli_register_kw, &cli_kws);
 
-#ifdef DEBUG_FAIL_ALLOC
-
-int mem_should_fail(const struct pool_head *pool)
-{
-	int ret = 0;
-
-	if (mem_fail_rate > 0 && !(global.mode & MODE_STARTING)) {
-		if (mem_fail_rate > statistical_prng_range(100))
-			ret = 1;
-		else
-			ret = 0;
-	}
-	return ret;
-
-}
 
 /* config parser for global "tune.fail-alloc" */
 static int mem_parse_global_fail_alloc(char **args, int section_type, struct proxy *curpx,
@@ -928,13 +926,10 @@ static int mem_parse_global_fail_alloc(char **args, int section_type, struct pro
 	}
 	return 0;
 }
-#endif
 
 /* register global config keywords */
 static struct cfg_kw_list mem_cfg_kws = {ILH, {
-#ifdef DEBUG_FAIL_ALLOC
 	{ CFG_GLOBAL, "tune.fail-alloc", mem_parse_global_fail_alloc },
-#endif
 	{ 0, NULL, NULL }
 }};