From: Vlastimil Babka <vbabka@suse.cz>
Date: Mon, 7 Aug 2023 18:50:44 +0000 (+0200)
Subject: mm/slub: fix bulk alloc and free stats
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=6f3dd2c31d7d703a814c59f60daf95c57fa6a4c2;p=linux.git

mm/slub: fix bulk alloc and free stats

The SLUB sysfs stats enabled CONFIG_SLUB_STATS have two deficiencies
identified wrt bulk alloc/free operations:

- Bulk allocations from cpu freelist are not counted. Add the
  ALLOC_FASTPATH counter there.

- Bulk fastpath freeing will count a list of multiple objects with a
  single FREE_FASTPATH inc. Add a stat_add() variant to count them all.

Reviewed-by: Chengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
---

diff --git a/mm/slub.c b/mm/slub.c
index 3f8b957571068..d7b0ca6012e02 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -396,6 +396,14 @@ static inline void stat(const struct kmem_cache *s, enum stat_item si)
 #endif
 }
 
+static inline
+void stat_add(const struct kmem_cache *s, enum stat_item si, int v)
+{
+#ifdef CONFIG_SLUB_STATS
+	raw_cpu_add(s->cpu_slab->stat[si], v);
+#endif
+}
+
 /*
  * The slab lists for all objects.
  */
@@ -4268,7 +4276,7 @@ redo:
 
 		local_unlock(&s->cpu_slab->lock);
 	}
-	stat(s, FREE_FASTPATH);
+	stat_add(s, FREE_FASTPATH, cnt);
 }
 #else /* CONFIG_SLUB_TINY */
 static void do_slab_free(struct kmem_cache *s,
@@ -4545,6 +4553,7 @@ static inline int __kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags,
 		c->freelist = get_freepointer(s, object);
 		p[i] = object;
 		maybe_wipe_obj_freeptr(s, p[i]);
+		stat(s, ALLOC_FASTPATH);
 	}
 	c->tid = next_tid(c->tid);
 	local_unlock_irqrestore(&s->cpu_slab->lock, irqflags);