From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2BBB2466B74; Wed, 10 Jun 2026 15:41:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781106079; cv=none; b=MeN8nFWISVCc/PPp33nYtHwzWmzLex316zpgXS8q7B/a+nF7WCB/Hq7h4JpWfRB2zW3uL4+24xxGR8BWuSgtaRgZxFU7w3hk9LTfM4z3vOADr2D8+/vThHXwc4y20x+v3CDPV/gU7XSz+difqBHqH9vlGRMRKxLSV+NY7unIdVs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781106079; c=relaxed/simple; bh=fuvEkNGOaa1Ud/36lrMH0EnDnBb52t0E2Z0UOSqbU5k=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=LoPQViINOxzYtal/ajZMu2MSsuFf/s9jywFn0M8TElPzsBg/uj8mYS99Zv9uZR3tWYwIIIvWgzgRXRGtYbGqrsaSSvl3RkwiSMOwHm+ztULxzTf1OIfVhGmFbFmF1rgIHKxICiDemdUh+BjheuRagHeFjAYIu06MnqEEHCnRcu4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=nIC4+tgu; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="nIC4+tgu" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3922E1F00893; Wed, 10 Jun 2026 15:41:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1781106077; bh=zw7OfgTsThDHzuQXS+OL+Mrf7Mf3Iw/m9nWLfYn615A=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=nIC4+tguZQTWq8AmKG92I9Jn9Q7ZciPLThGgiggAl2kImmdgWPpBQenefZeEvZRlx ey5e2PnNze0f+V3yjUZarwjMTpXmCZeH+YkpxeTzLUYWfr8qcI6FMNVFNa0666iQd+ 3Rm3WN2juaXNqUcFbjgtIcFY1gcJM52rNy9hoN1tqd7h85HqHkjl/u6VxBwv1KmPno kcdu1liXPl9KXtdVvu1btuA1W57iiBEFl/2Mg169S39LQB+ANgVEe4zn8UyDjlRqfS PpxQ1lvKTKgF7ZcW+3qjhHRH12ZVTaRYU0W3gACrtD4bbBYFpS0JlUuuHKw/PcAUiX rltrfMALmUqrw== From: "Vlastimil Babka (SUSE)" Date: Wed, 10 Jun 2026 17:40:10 +0200 Subject: [PATCH v2 08/16] mm/slab: pass alloc_flags to new slab allocation Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260610-slab_alloc_flags-v2-8-7190909db118@kernel.org> References: <20260610-slab_alloc_flags-v2-0-7190909db118@kernel.org> In-Reply-To: <20260610-slab_alloc_flags-v2-0-7190909db118@kernel.org> To: Harry Yoo Cc: Hao Li , Christoph Lameter , David Rientjes , Roman Gushchin , Suren Baghdasaryan , Alexei Starovoitov , Andrew Morton , Johannes Weiner , Michal Hocko , Shakeel Butt , Alexander Potapenko , Marco Elver , Dmitry Vyukov , kasan-dev@googlegroups.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, "Vlastimil Babka (SUSE)" X-Mailer: b4 0.15.2 Add the alloc_flags parameter to allocate_slab() and new_slab() so it can be used to determine if spinning is allowed, independently from gfp flags. refill_objects() passes SLAB_ALLOC_DEFAULT because it can only be reached from contexts that allow spinning. Also change how trynode_flags are constructed in ___slab_alloc() to achieve the same "do not upgrade to GFP_NOWAIT" by using masking instead of a branch. It will now also not upgrade in cases where gfp is weaker than GFP_NOWAIT (i.e. lacks __GFP_KSWAPD_RECLAIM) but doesn't come from kmalloc_nolock() - which is more correct anyway. During the masking keep also existing __GFP_NOMEMALLOC (pointed out by Sashiko) and __GFP_ACCOUNT. Previously the hardcoded GFP_NOWAIT would eliminate them, but it's not a big problem that would need a separate fix. Signed-off-by: Vlastimil Babka (SUSE) --- mm/slub.c | 28 ++++++++++++++-------------- 1 file changed, 14 insertions(+), 14 deletions(-) diff --git a/mm/slub.c b/mm/slub.c index 98b79e5e7679..8f6ca3d5fdfa 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -3378,9 +3378,10 @@ static __always_inline void unaccount_slab(struct slab *slab, int order, } /* Allocate and initialize a slab without building its freelist. */ -static struct slab *allocate_slab(struct kmem_cache *s, gfp_t flags, int node) +static struct slab *allocate_slab(struct kmem_cache *s, gfp_t flags, + unsigned int alloc_flags, int node) { - bool allow_spin = gfpflags_allow_spinning(flags); + bool allow_spin = alloc_flags_allow_spinning(alloc_flags); struct slab *slab; struct kmem_cache_order_objects oo = s->oo; gfp_t alloc_gfp; @@ -3438,15 +3439,17 @@ static struct slab *allocate_slab(struct kmem_cache *s, gfp_t flags, int node) return slab; } -static struct slab *new_slab(struct kmem_cache *s, gfp_t flags, int node) +static struct slab *new_slab(struct kmem_cache *s, gfp_t flags, + unsigned int alloc_flags, int node) { if (unlikely(flags & GFP_SLAB_BUG_MASK)) flags = kmalloc_fix_flags(flags); WARN_ON_ONCE(s->ctor && (flags & __GFP_ZERO)); - return allocate_slab(s, - flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node); + flags &= GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK; + + return allocate_slab(s, flags, alloc_flags, node); } static void __free_slab(struct kmem_cache *s, struct slab *slab, bool allow_spin) @@ -4467,25 +4470,22 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node, * 1) try to get a partial slab from target node only by having * __GFP_THISNODE in pc.flags for get_from_partial() * 2) if 1) failed, try to allocate a new slab from target node with - * GPF_NOWAIT | __GFP_THISNODE opportunistically + * (at most) GFP_NOWAIT | __GFP_THISNODE opportunistically * 3) if 2) failed, retry with original gfpflags which will allow * get_from_partial() try partial lists of other nodes before * potentially allocating new page from other nodes */ if (unlikely(node != NUMA_NO_NODE && !(gfpflags & __GFP_THISNODE) && try_thisnode)) { - if (unlikely(!allow_spin)) - /* Do not upgrade gfp to NOWAIT from more restrictive mode */ - trynode_flags = gfpflags | __GFP_THISNODE; - else - trynode_flags = GFP_NOWAIT | __GFP_THISNODE; + trynode_flags &= GFP_NOWAIT | __GFP_NOMEMALLOC | __GFP_ACCOUNT; + trynode_flags |= __GFP_NOWARN | __GFP_THISNODE; } object = get_from_partial(s, node, trynode_flags, ac); if (object) goto success; - slab = new_slab(s, trynode_flags, node); + slab = new_slab(s, trynode_flags, ac->alloc_flags, node); if (unlikely(!slab)) { if (node != NUMA_NO_NODE && !(gfpflags & __GFP_THISNODE) @@ -7231,7 +7231,7 @@ refill_objects(struct kmem_cache *s, void **p, gfp_t gfp, unsigned int min, new_slab: - slab = new_slab(s, gfp, local_node); + slab = new_slab(s, gfp, SLAB_ALLOC_DEFAULT, local_node); if (!slab) goto out; @@ -7579,7 +7579,7 @@ static void early_kmem_cache_node_alloc(int node) BUG_ON(kmem_cache_node->size < sizeof(struct kmem_cache_node)); - slab = new_slab(kmem_cache_node, GFP_NOWAIT, node); + slab = new_slab(kmem_cache_node, GFP_NOWAIT, SLAB_ALLOC_DEFAULT, node); BUG_ON(!slab); if (slab_nid(slab) != node) { -- 2.54.0