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 B8DD33DA5BD; Mon, 15 Jun 2026 10:14:28 +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=1781518469; cv=none; b=VPUm9tpDh0Ht1VYF/Lt9mYeOJVfOFzZ5wTt0uoD5l0ZqFUc+pDU3PT+IXoK6JPPs73CHTNOmPEwGI1DqJQNMGW7nVQcn8CG9P+YNrAVCRI0twwmiqk7IzztY3COWxcZMOBZyRBdOm2Iai2s5ZNNn9pbxxIF5oMZE0e/5lG1ELk0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781518469; c=relaxed/simple; bh=+i98OB42+NmLa3evPR0ZxhKnbDfP9M9EeKCMjPpXO+w=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=GsAsT3tIGaJTFEb1KzY42y99G93Yxpc4nXC69jTxslVk39K6K5JYDcdUQkMR5TmPxz1lIxW659ZEttCgJbhvSlUqlHAjofh3ldTmSDH7pwORJ5OCV/8j69Lo6J51vgWgVtgIJL+EuLsg2MypJbKaYxd/G9sVOd1I78WjUdDZRcM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=SMyTsyB4; 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="SMyTsyB4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id ECAD01F000E9; Mon, 15 Jun 2026 10:14:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1781518468; bh=T2eZ9nicY2ugL7ZhQhUMhUTF6916IovA3mkaq4lvaXQ=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=SMyTsyB4ltrLipBSuP0C8l+bwRDWSEU8kLkUu3IZFNMNtDlBEECikDD7LhyvijU6/ vhQ+DM8JhL7di73ZhtNnlP3vASRDKZuEAYGK45GD1KfRCD4M49tR9ICRlmBQ6k539+ 3kVjBCWjy6QvLFtduPqVzFr5X9qdXVvvK+rbuI11cyr+6/OL3k2IEiv8yhCCrVmNLT vhrog67BSpEEJZTdC9V+n02oPykFZ1kAyMW5AXPcwQim26LKaEmXySqsV/xv0UY7Jw dv5Yxv+YBN5C108+p6CgA8yiKv0qfkTKFJXoOJ09YSJvDNT2c6+TFVe6bjjWmC9l0X H8Xcd2iTnrBWQ== Message-ID: <3f454a59-71d0-4354-87d6-85afb91a4ae2@kernel.org> Date: Mon, 15 Jun 2026 12:14:23 +0200 Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 08/16] mm/slab: pass alloc_flags to new slab allocation Content-Language: en-US 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 References: <20260610-slab_alloc_flags-v2-0-7190909db118@kernel.org> <20260610-slab_alloc_flags-v2-8-7190909db118@kernel.org> <49ca905a-0303-4fad-8257-485b0ed47c8d@kernel.org> From: "Vlastimil Babka (SUSE)" Autocrypt: addr=vbabka@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 6/11/26 09:52, Harry Yoo wrote: > > > On 6/11/26 12:40 AM, Vlastimil Babka (SUSE) wrote: >> 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. > > Wait, debugobjects intentionally avoids __GFP_KSWAPD_RECLAIM, > but we have been upgrading it to GFP_NOWAIT? Actually, we have not been upgrading it until patch 6/16, which made the upgrade trigger by starting to rely on alloc_flags? Because previously it would be !allow_spin due to lack of __GFP_KSWAPD_RECLAIM. So I will move that flags adjustment to 6/16 (now 7/16). >> 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. > > Ack. > >> 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 >> @@ -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; >> } >