linux-kernel - [PATCH 1/2] mm: slub: allocate slab object extensions non-contiguously

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Message-ID: <20250520122547.1317050-1-usamaarif642@gmail.com>
Date: Tue, 20 May 2025 13:25:46 +0100
From: Usama Arif <usamaarif642@...il.com>
To: Andrew Morton <akpm@...ux-foundation.org>,
	surenb@...gle.com
Cc: hannes@...xchg.org,
	shakeel.butt@...ux.dev,
	vlad.wing@...il.com,
	linux-mm@...ck.org,
	kent.overstreet@...ux.dev,
	linux-kernel@...r.kernel.org,
	kernel-team@...a.com,
	Usama Arif <usamaarif642@...il.com>
Subject: [PATCH 1/2] mm: slub: allocate slab object extensions non-contiguously

When memory allocation profiling is running on memory bound services,
allocations greater than order 0 for slab object extensions can fail,
for e.g. zs_handle zswap slab which will be 512 objsperslab x 16 bytes
per slabobj_ext (order 1 allocation). Use kvcalloc to improve chances
of the allocation being successful.

Signed-off-by: Usama Arif <usamaarif642@...il.com>
Reported-by: Vlad Poenaru <vlad.wing@...il.com>
Closes: https://lore.kernel.org/all/17fab2d6-5a74-4573-bcc3-b75951508f0a@gmail.com/
---
 mm/slub.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/slub.c b/mm/slub.c
index dc9e729e1d26..bf43c403ead2 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1989,7 +1989,7 @@ int alloc_slab_obj_exts(struct slab *slab, struct kmem_cache *s,
 	gfp &= ~OBJCGS_CLEAR_MASK;
 	/* Prevent recursive extension vector allocation */
 	gfp |= __GFP_NO_OBJ_EXT;
-	vec = kcalloc_node(objects, sizeof(struct slabobj_ext), gfp,
+	vec = kvcalloc_node(objects, sizeof(struct slabobj_ext), gfp,
 			   slab_nid(slab));
 	if (!vec) {
 		/* Mark vectors which failed to allocate */
-- 
2.47.1