From 021ca6b670bebebc409d43845efcfe8c11c1dd54 Mon Sep 17 00:00:00 2001 From: Harry Yoo Date: Mon, 23 Feb 2026 22:33:22 +0900 Subject: [PATCH] mm/slab: pass __GFP_NOWARN to refill_sheaf() if fallback is available When refill_sheaf() is called, failing to refill the sheaf doesn't necessarily mean the allocation will fail because a fallback path might be available and serve the allocation request. Suppress spurious warnings by passing __GFP_NOWARN along with __GFP_NOMEMALLOC whenever a fallback path is available. When the caller is alloc_full_sheaf() or __pcs_replace_empty_main(), the kernel always falls back to the slowpath (__slab_alloc_node()). For __prefill_sheaf_pfmemalloc(), the fallback path is available only when gfp_pfmemalloc_allowed() returns true. Reported-and-tested-by: Chris Bainbridge Closes: https://lore.kernel.org/linux-mm/aZt2-oS9lkmwT7Ch@debian.local Fixes: 1ce20c28eafd ("slab: handle pfmemalloc slabs properly with sheaves") Link: https://lore.kernel.org/linux-mm/aZwSreGj9-HHdD-j@hyeyoo Signed-off-by: Harry Yoo Link: https://patch.msgid.link/20260223133322.16705-1-harry.yoo@oracle.com Tested-by: Mikhail Gavrilov Signed-off-by: Vlastimil Babka (SUSE) --- mm/slub.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/mm/slub.c b/mm/slub.c index 862642c165ed..4ce24d9ee7e4 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -2822,7 +2822,7 @@ static struct slab_sheaf *alloc_full_sheaf(struct kmem_cache *s, gfp_t gfp) if (!sheaf) return NULL; - if (refill_sheaf(s, sheaf, gfp | __GFP_NOMEMALLOC)) { + if (refill_sheaf(s, sheaf, gfp | __GFP_NOMEMALLOC | __GFP_NOWARN)) { free_empty_sheaf(s, sheaf); return NULL; } @@ -4575,7 +4575,7 @@ __pcs_replace_empty_main(struct kmem_cache *s, struct slub_percpu_sheaves *pcs, return NULL; if (empty) { - if (!refill_sheaf(s, empty, gfp | __GFP_NOMEMALLOC)) { + if (!refill_sheaf(s, empty, gfp | __GFP_NOMEMALLOC | __GFP_NOWARN)) { full = empty; } else { /* @@ -4890,9 +4890,14 @@ EXPORT_SYMBOL(kmem_cache_alloc_node_noprof); static int __prefill_sheaf_pfmemalloc(struct kmem_cache *s, struct slab_sheaf *sheaf, gfp_t gfp) { - int ret = 0; + gfp_t gfp_nomemalloc; + int ret; - ret = refill_sheaf(s, sheaf, gfp | __GFP_NOMEMALLOC); + gfp_nomemalloc = gfp | __GFP_NOMEMALLOC; + if (gfp_pfmemalloc_allowed(gfp)) + gfp_nomemalloc |= __GFP_NOWARN; + + ret = refill_sheaf(s, sheaf, gfp_nomemalloc); if (likely(!ret || !gfp_pfmemalloc_allowed(gfp))) return ret;