MINOR: activity: report the number of failed pool/buffer allocations

Haproxy is designed to be able to continue to run even under very low
memory conditions. However this can sometimes have a serious impact on
performance that it hard to diagnose. Let's report counters of failed
pool and buffer allocations per thread in show activity.

include/common/buffer.h

@@ -33,6 +33,7 @@
 #include <common/istbuf.h>
 #include <common/memory.h>
 
+#include <proto/activity.h>
 
 /* an element of the <buffer_wq> list. It represents an object that need to
  * acquire a buffer to continue its process. */
@@ -77,8 +78,10 @@ static inline struct buffer *b_alloc(struct buffer *buf)
 
 	*buf = BUF_WANTED;
 	area = pool_alloc_dirty(pool_head_buffer);
-	if (unlikely(!area))
+	if (unlikely(!area)) {
+		activity[tid].buf_wait++;
 		return NULL;
+	}
 
 	buf->area = area;
 	buf->size = pool_head_buffer->size;
@@ -175,8 +178,10 @@ static inline struct buffer *b_alloc_margin(struct buffer *buf, int margin)
 	HA_SPIN_UNLOCK(POOL_LOCK, &pool_head_buffer->lock);
 #endif
 
-	if (unlikely(!area))
+	if (unlikely(!area)) {
+		activity[tid].buf_wait++;
 		return NULL;
+	}
 
  done:
 	buf->area = area;

include/types/activity.h

@@ -54,6 +54,8 @@ struct activity {
 	unsigned int accepted;     // accepted incoming connections
 	unsigned int accq_pushed;  // accept queue connections pushed
 	unsigned int accq_full;    // accept queue connection not pushed because full
+	unsigned int pool_fail;    // failed a pool allocation
+	unsigned int buf_wait;     // waited on a buffer allocation
 #if defined(DEBUG_DEV)
 	/* keep these ones at the end */
 	unsigned int ctr0;         // general purposee debug counter

src/cli.c

@@ -1117,6 +1117,8 @@ static int cli_io_handler_show_activity(struct appctx *appctx)
 	chunk_appendf(&trash, "fd_lock:");      SHOW_TOT(thr, activity[thr].fd_lock);
 	chunk_appendf(&trash, "conn_dead:");    SHOW_TOT(thr, activity[thr].conn_dead);
 	chunk_appendf(&trash, "stream:");       SHOW_TOT(thr, activity[thr].stream);
+	chunk_appendf(&trash, "pool_fail:");    SHOW_TOT(thr, activity[thr].pool_fail);
+	chunk_appendf(&trash, "buf_wait:");     SHOW_TOT(thr, activity[thr].buf_wait);
 	chunk_appendf(&trash, "empty_rq:");     SHOW_TOT(thr, activity[thr].empty_rq);
 	chunk_appendf(&trash, "long_rq:");      SHOW_TOT(thr, activity[thr].long_rq);
 	chunk_appendf(&trash, "ctxsw:");        SHOW_TOT(thr, activity[thr].ctxsw);

src/memory.c

@@ -25,6 +25,8 @@
 #include <common/mini-clist.h>
 #include <common/standard.h>
 
+#include <types/activity.h>
+
 #include <proto/applet.h>
 #include <proto/cli.h>
 #include <proto/channel.h>
@@ -160,14 +162,17 @@ void *__pool_refill_alloc(struct pool_head *pool, unsigned int avail)
 	while (1) {
 		if (limit && allocated >= limit) {
 			_HA_ATOMIC_ADD(&pool->allocated, allocated - allocated_orig);
+			activity[tid].pool_fail++;
 			return NULL;
 		}
 
 		ptr = malloc(size + POOL_EXTRA);
 		if (!ptr) {
 			_HA_ATOMIC_ADD(&pool->failed, 1);
-			if (failed)
+			if (failed) {
+				activity[tid].pool_fail++;
 				return NULL;
+			}
 			failed++;
 			pool_gc(pool);
 			continue;
@@ -317,14 +322,18 @@ void *__pool_refill_alloc(struct pool_head *pool, unsigned int avail)
 	avail += pool->used;
 
 	while (1) {
-		if (pool->limit && pool->allocated >= pool->limit)
+		if (pool->limit && pool->allocated >= pool->limit) {
+			activity[tid].pool_fail++;
 			return NULL;
+		}
 
 		ptr = pool_alloc_area(pool->size + POOL_EXTRA);
 		if (!ptr) {
 			pool->failed++;
-			if (failed)
+			if (failed) {
+				activity[tid].pool_fail++;
 				return NULL;
+			}
 			failed++;
 			pool_gc(pool);
 			continue;