From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-171.mta1.migadu.com (out-171.mta1.migadu.com [95.215.58.171]) (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 546402367DC for ; Fri, 13 Mar 2026 18:29:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.171 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773426553; cv=none; b=jFwfKosC8J61R4ZbHMJSdNeX5jAWQw/Irezo92UDDqlJhc7nweUnJstC56HZ9Bs2Qs6J60cogwjSmX/uSz8FMrjw8Y8CXayQVLi+UXt5rMBNJ8Maecl2spG+6DFLTEd5eRk4AxZFL/zVCMguC/UMbubf7a+YYr1XS2qL02XaUmU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773426553; c=relaxed/simple; bh=beT3slSxigQWpRi2wAgooEEIOo5XJcpPrhDfU9dsQZI=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=oyIDLlzDnTSnKImaSslqBsLjXDQv5z1r6PtHc68wmOCh4vNILSIUk1IN3ckGWO5c7ZRiQj0ksw6sBY7AjF1tVyLiYPvVBcMM99BVgEkA+jSzLunDxEztd90BeMiJLG5dD3PO6Q9hyhqsZEfQODXBiyUbx477Tahx4yYQHfXuWQE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=gOjsee/7; arc=none smtp.client-ip=95.215.58.171 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="gOjsee/7" Message-ID: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1773426547; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Pv/nqWXHkfj7NbNE0aFGYmPjuMP96PKFI4ITkk92xic=; b=gOjsee/7ePXLg2aXVQRCN98jWrWOJGc7S6Od5X5MCK2XmZiOGkbnjW7aiGdNYAKZEniFby yIlBZdhFvB+0R6tKrR+2QHRw41SgEFGPECC6cQR00lVPRhhcghOc3/uCGAMO4OCyycW0lq ZTmH8SsM0A6v+7eY3IHoq5fzhd3ix7E= Date: Fri, 13 Mar 2026 11:28:52 -0700 Precedence: bulk X-Mailing-List: virtualization@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH v2] mm/mempolicy: track page allocations per mempolicy To: "Huang, Ying" , "Vlastimil Babka (SUSE)" Cc: 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 References: <20260307045520.247998-1-jp.kobryn@linux.dev> <3a42463b-9ddd-4d64-b64c-6c2e6e4fc75d@kernel.org> <343bbd5b-67a0-46c4-8ec4-69158bf26b3f@linux.dev> <874imkpba1.fsf@DESKTOP-5N7EMDA> <60f71f4c-71d9-4751-8c6b-10179b98bef0@kernel.org> <87zf4cnkip.fsf@DESKTOP-5N7EMDA> Content-Language: en-US X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: "JP Kobryn (Meta)" In-Reply-To: <87zf4cnkip.fsf@DESKTOP-5N7EMDA> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT On 3/13/26 2:31 AM, Huang, Ying wrote: > "Vlastimil Babka (SUSE)" writes: > >> On 3/13/26 07:14, JP Kobryn (Meta) wrote: >>> On 3/12/26 10:07 PM, Huang, Ying wrote: >>>> "JP Kobryn (Meta)" writes: >>>> >>>>> On 3/12/26 6:40 AM, Vlastimil Babka (SUSE) wrote: >>>>> >>>>> 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? >>> >>> The existing counters don't account for node masks in the policies that >>> make use of them. An allocation can land on a node in the mask and still >>> be considered a miss because it wasn't the preferred node. >> >> That sounds like we could just a new counter e.g. numa_hit_preferred and >> adjust definitions accordingly? Or some other variant that fills the gap? > > Or can we adjust the semantics of numa_hit/miss/foreign to consider the > preferred nodemask instead of the preferred node? Is there some > programs to depends on the current behavior? Good question. I think it comes down to whether the existing semantics are correct with respect to policies that make use of node masks. I gave some thoughts on this in the previous reply to Vlastimil. That correctness may be outside of the scope of this patch, but I can give that a try afterward. I'd like to send a revision that reduces the new counters to just 3 and moves them off of the memcg (as previously mentioned in thread). I know numastat is one consumer of the existing stats. It seems up to the user on the interpretation of the data. Not sure about others.