From 1a787779fe2a9b5d042b5b54f3580eb3802404c4 Mon Sep 17 00:00:00 2001 From: "Vlastimil Babka (SUSE)" Date: Wed, 10 Jun 2026 17:40:13 +0200 Subject: [PATCH] mm/slab: allow kmem_cache_alloc_bulk() with any gfp flags The last user of gfpflags_allow_spinning() in slab is alloc_from_pcs_bulk(), which is only called from kmem_cache_alloc_bulk(). It turns out that gfpflags_allow_spinning() is not necessary, because kmem_cache_alloc_bulk() is only expected to be called from context that does allow spinning, so simply replace it with 'true'. This means we can also drop the gfp parameter from alloc_from_pcs_bulk(). With that, we can remove the "@flags must allow spinning" part of the kernel doc, as there is no more connection to the gfp flags in the slab implementation. Also remove a comment in alloc_slab_obj_exts() because there should be no more false positives possible due to gfp_allowed_mask during early boot. Link: https://patch.msgid.link/20260610-slab_alloc_flags-v2-11-7190909db118@kernel.org Reviewed-by: Suren Baghdasaryan Reviewed-by: Harry Yoo (Oracle) Reviewed-by: Hao Li Signed-off-by: Vlastimil Babka (SUSE) --- mm/slub.c | 16 ++++------------ 1 file changed, 4 insertions(+), 12 deletions(-) diff --git a/mm/slub.c b/mm/slub.c index 562495b80d74..81938774098b 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -2171,12 +2171,6 @@ int alloc_slab_obj_exts(struct slab *slab, struct kmem_cache *s, sz = obj_exts_alloc_size(s, slab, gfp); - /* - * Note that allow_spin may be false during early boot and its - * restricted GFP_BOOT_MASK. Due to kmalloc_nolock() only supporting - * architectures with cmpxchg16b, early obj_exts will be missing for - * very early allocations on those. - */ if (unlikely(!allow_spin)) vec = kmalloc_nolock(sz, __GFP_ZERO | __GFP_NO_OBJ_EXT, slab_nid(slab)); @@ -4830,8 +4824,7 @@ void *alloc_from_pcs(struct kmem_cache *s, gfp_t gfp, unsigned int alloc_flags, } static __fastpath_inline -unsigned int alloc_from_pcs_bulk(struct kmem_cache *s, gfp_t gfp, size_t size, - void **p) +unsigned int alloc_from_pcs_bulk(struct kmem_cache *s, size_t size, void **p) { struct slub_percpu_sheaves *pcs; struct slab_sheaf *main; @@ -4866,7 +4859,7 @@ unsigned int alloc_from_pcs_bulk(struct kmem_cache *s, gfp_t gfp, size_t size, } full = barn_replace_empty_sheaf(barn, pcs->main, - gfpflags_allow_spinning(gfp)); + /* allow_spin = */ true); if (full) { stat(s, BARN_GET); @@ -7331,8 +7324,7 @@ static bool __kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, * Allocate @size objects from @s and places them into @p. @size must be larger * than 0. * - * Interrupts must be enabled when calling this function and @flags must allow - * spinning. + * Interrupts must be enabled when calling this function. * * Unlike alloc_pages_bulk(), this function does not check for already allocated * objects in @p, and thus the caller does not need to zero it. @@ -7370,7 +7362,7 @@ bool kmem_cache_alloc_bulk_noprof(struct kmem_cache *s, gfp_t flags, size--; } - i = alloc_from_pcs_bulk(s, flags, size, p); + i = alloc_from_pcs_bulk(s, size, p); if (i < size) { /* * If we ran out of memory, don't bother with freeing back to