From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out30-112.freemail.mail.aliyun.com (out30-112.freemail.mail.aliyun.com [115.124.30.112]) (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 ED99A1D6195 for ; Fri, 13 Mar 2026 05:08:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.112 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773378488; cv=none; b=qDdONa2rAa+BVaZtnJNgaS7VPUigSzbYsil0qiOdr7dIrkx3FUXmzXGGFjZeYKbTSTbf4/wwbc2VcV/evyWEOowXo1UuzZKdVHQzJqlnMOpHqw9bO6wN80WbIAw9Jg+oKekEIoFUJwW1tsVaZGioAQ99G7yyAXkifKS7O3IE6zg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773378488; c=relaxed/simple; bh=973I4MvM6diQkbCEVFTHHCxVl0F1i7DrNqJaYcqqqFE=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=cWej9zpAthql0j03dZdUB9CzHAQ6kfKqQ+BEz26t2AU+kU/qD7mkwYMxwkfR7plxHO5ugwGnqFU1f/QrTUFB5C4orxsw1mRI3BazNz1J9NbhwjAvCK28x+INJfS8J4wcpGOFoznUyk068iqHlENAhOLV7Ffqd2+Rv+3kpxVQt+c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b=K9+yRy1m; arc=none smtp.client-ip=115.124.30.112 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="K9+yRy1m" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1773378475; h=From:To:Subject:Date:Message-ID:MIME-Version:Content-Type; bh=T2fdojMM54qSgNsuFhPwacfFSNjW/hMMNErtovdaSec=; b=K9+yRy1maHL6dE99fG6FnmFTzHdPeR/Y2U5+rMAnH4ssIC2H0Y9pCjP5Q0tjqYR8eRmHzQIRbNXmbGWmA9z7fnpP/UDXYUg2a6pfR25aO1iHP5ymkh9cqxtxLxjSJqrNmF/+KnQXj3VaW9Ub+UtPRX2xYfXY08jHFkBsAKQA9Mo= X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R451e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=maildocker-contentspam033045133197;MF=ying.huang@linux.alibaba.com;NM=1;PH=DS;RN=33;SR=0;TI=SMTPD_---0X-r.uEE_1773378471; Received: from DESKTOP-5N7EMDA(mailfrom:ying.huang@linux.alibaba.com fp:SMTPD_---0X-r.uEE_1773378471 cluster:ay36) by smtp.aliyun-inc.com; Fri, 13 Mar 2026 13:07:53 +0800 From: "Huang, Ying" To: "JP Kobryn (Meta)" Cc: "Vlastimil Babka (SUSE)" , linux-mm@kvack.org, akpm@linux-foundation.org, mhocko@suse.com, apopple@nvidia.com, axelrasmussen@google.com, byungchul@sk.com, cgroups@vger.kernel.org, david@kernel.org, eperezma@redhat.com, gourry@gourry.net, jasowang@redhat.com, hannes@cmpxchg.org, joshua.hahnjy@gmail.com, Liam.Howlett@oracle.com, linux-kernel@vger.kernel.org, lorenzo.stoakes@oracle.com, matthew.brost@intel.com, mst@redhat.com, rppt@kernel.org, muchun.song@linux.dev, zhengqi.arch@bytedance.com, rakie.kim@sk.com, roman.gushchin@linux.dev, shakeel.butt@linux.dev, surenb@google.com, virtualization@lists.linux.dev, weixugc@google.com, xuanzhuo@linux.alibaba.com, yuanchu@google.com, ziy@nvidia.com, kernel-team@meta.com Subject: Re: [PATCH v2] mm/mempolicy: track page allocations per mempolicy In-Reply-To: <343bbd5b-67a0-46c4-8ec4-69158bf26b3f@linux.dev> (JP Kobryn's message of "Thu, 12 Mar 2026 09:13:49 -0700") References: <20260307045520.247998-1-jp.kobryn@linux.dev> <3a42463b-9ddd-4d64-b64c-6c2e6e4fc75d@kernel.org> <343bbd5b-67a0-46c4-8ec4-69158bf26b3f@linux.dev> Date: Fri, 13 Mar 2026 13:07:50 +0800 Message-ID: <874imkpba1.fsf@DESKTOP-5N7EMDA> User-Agent: Gnus/5.13 (Gnus v5.13) Precedence: bulk X-Mailing-List: virtualization@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ascii "JP Kobryn (Meta)" writes: > On 3/12/26 6:40 AM, Vlastimil Babka (SUSE) wrote: >> On 3/7/26 05:55, JP Kobryn (Meta) wrote: >>> When investigating pressure on a NUMA node, there is no straightforward way >>> to determine which policies are driving allocations to it. >>> >>> Add per-policy page allocation counters as new node stat items. These >>> counters track allocations to nodes and also whether the allocations were >>> intentional or fallbacks. >>> >>> The new stats follow the existing numa hit/miss/foreign style and have the >>> following meanings: >>> >>> hit >>> - for BIND and PREFERRED_MANY, allocation succeeded on node in nodemask >>> - for other policies, allocation succeeded on intended node >>> - counted on the node of the allocation >>> miss >>> - allocation intended for other node, but happened on this one >>> - counted on other node >>> foreign >>> - allocation intended on this node, but happened on other node >>> - counted on this node >>> >>> Counters are exposed per-memcg, per-node in memory.numa_stat and globally >>> in /proc/vmstat. >>> >>> Signed-off-by: JP Kobryn (Meta) >> I think I've been on of the folks on previous versions arguing >> against the >> many counters, and one of the arguments was it they can't tell the full >> story anyway (compared to e.g. tracing), but I don't think adding even more >> counters is the right solution. Seems like a number of other people >> responding to the thread are providing similar feedback. >> For example I'm still not sure how it would help me if I knew the >> hits/misses were due to a preferred vs preferred_many policy, or interleave >> vs weithed interleave? >> > > How about I change from per-policy hit/miss/foreign triplets to a single > aggregated policy triplet (i.e. just 3 new counters which account for > all policies)? They would follow the same hit/miss/foreign semantics > already proposed (visible in quoted text above). This would still > provide the otherwise missing signal of whether policy-driven > allocations to a node are intentional or fallback. > > Note that I am also planning on moving the stats off of the memcg so the > 3 new counters will be global per-node in response to similar feedback. Emm, what's the difference between these newly added counters and the existing numa_hit/miss/foreign counters? --- Best Regards, Huang, Ying