From 16fcda24b17507f2bb584e14dec5285301528f52 Mon Sep 17 00:00:00 2001 From: Roman Gushchin Date: Tue, 7 Nov 2023 09:18:02 -0800 Subject: [PATCH] mm: kmem: drop __GFP_NOFAIL when allocating objcg vectors commit 24948e3b7b12e0031a6edb4f49bbb9fb2ad1e4e9 upstream. Objcg vectors attached to slab pages to store slab object ownership information are allocated using gfp flags for the original slab allocation. Depending on slab page order and the size of slab objects, objcg vector can take several pages. If the original allocation was done with the __GFP_NOFAIL flag, it triggered a warning in the page allocation code. Indeed, order > 1 pages should not been allocated with the __GFP_NOFAIL flag. Fix this by simply dropping the __GFP_NOFAIL flag when allocating the objcg vector. It effectively allows to skip the accounting of a single slab object under a heavy memory pressure. An alternative would be to implement the mechanism to fallback to order-0 allocations for accounting metadata, which is also not perfect because it will increase performance penalty and memory footprint of the kernel memory accounting under memory pressure. Link: https://lkml.kernel.org/r/ZUp8ZFGxwmCx4ZFr@P9FQF9L96D.corp.robot.car Signed-off-by: Roman Gushchin Reported-by: Christoph Lameter Closes: https://lkml.kernel.org/r/6b42243e-f197-600a-5d22-56bd728a5ad8@gentwo.org Acked-by: Shakeel Butt Cc: Matthew Wilcox Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- mm/memcontrol.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index dacbaf4f7b2c..9da98e3e71cf 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2854,7 +2854,8 @@ static void commit_charge(struct folio *folio, struct mem_cgroup *memcg) * Moreover, it should not come from DMA buffer and is not readily * reclaimable. So those GFP bits should be masked off. */ -#define OBJCGS_CLEAR_MASK (__GFP_DMA | __GFP_RECLAIMABLE | __GFP_ACCOUNT) +#define OBJCGS_CLEAR_MASK (__GFP_DMA | __GFP_RECLAIMABLE | \ + __GFP_ACCOUNT | __GFP_NOFAIL) /* * mod_objcg_mlstate() may be called with irq enabled, so