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 4E4413F4831; Tue, 9 Jun 2026 09:18:22 +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=1780996703; cv=none; b=cS1qWjqPVtEc0ZfgrC85U6wupjmvgJOLvI7BJqobzg3CCGb1xF8JyatHa0WIOzVsdK8NzcTlrZpp/1WWowfAoRyqH4Q8HZHV62v9/CAyCuY2iiaojNEk9fioNuCMHYZ5+LKIPA4fg7pmEI/RKjC26PV6TQTgGnxXB7y/EAhsToo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780996703; c=relaxed/simple; bh=sjEEzLRuaqLLAW55S/ondGJWXtmb85RaReSQIT51yGc=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=GWeq6LbyC9OI2uQroAwGOS69Cfep4jrSxa5swvC9eBfnOpQPxK3kPFK6VaWtbEt9He5DFckH6vczY2p5rVwOS1AUBa9gcVUb0TiTK/ISdAVeIsD3iuEbclYX18m+gYyEgnG7AgguSGE2Mno5JKfuM4WnET9ESdRXIcxBH2KMt2A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=UtZ6gzxN; 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="UtZ6gzxN" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B1DAE1F00899; Tue, 9 Jun 2026 09:18:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1780996702; bh=lUdhGEsiIkmEk98q3M/PwP2pTSml7IktU/L4N6zTfjk=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=UtZ6gzxNRqJnwAm06gvctWhYRD1xV7p2uYuLW7IkT76bgUGxQilzhLe4h3POLT3Rl Fli0goPoJ6XbQS+O5oCeQfJ2cbwUPao6Zwqtf+P8nkcgt3cTTd624a1s0d+g+IVCPd ZV6sDEdiH4Hf9pRMTAiPubWpczu7irXpSc0IYDV0v3CuiqqhVdy8Xw4yRIyXh+SB1N N8NJgQTKSPWxWf5J9DFruOAPnOi3MpleCxvmh9/O/zXFevg1klFbMT0NQ8G9k7exJb gkY0drGG8uu275WdSpHbUjFN7uGnWgkl2HKp+8MejZtPbku79OJZogCD86MRsJD8dk ZZSeyyeLJAWLg== From: "Vlastimil Babka (SUSE)" Date: Tue, 09 Jun 2026 11:17:52 +0200 Subject: [PATCH RFC 07/15] 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: <20260609-slab_alloc_flags-v1-7-2bf4a4b9b526@kernel.org> References: <20260609-slab_alloc_flags-v1-0-2bf4a4b9b526@kernel.org> In-Reply-To: <20260609-slab_alloc_flags-v1-0-2bf4a4b9b526@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. 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 0bde4f6d9126..20df6b131f63 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) GPF_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; + 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) @@ -7215,7 +7215,7 @@ 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; @@ -7563,7 +7563,7 @@ 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