From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 774F7C55838 for ; Thu, 6 Aug 2026 06:26:26 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 51C056B007B; Thu, 6 Aug 2026 02:26:25 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 4CD596B0088; Thu, 6 Aug 2026 02:26:25 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3BB406B008A; Thu, 6 Aug 2026 02:26:25 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 1505C6B007B for ; Thu, 6 Aug 2026 02:26:25 -0400 (EDT) Received: from smtpin29.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 0302D80680 for ; Thu, 6 Aug 2026 06:26:22 +0000 (UTC) X-FDA: 85069860246.29.CDA7586 Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf04.hostedemail.com (Postfix) with ESMTP id 68DE640008 for ; Thu, 6 Aug 2026 06:26:21 +0000 (UTC) Authentication-Results: imf04.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=FE7aXVZP; spf=pass (imf04.hostedemail.com: domain of ljs@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=ljs@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1785997581; b=0W3W8uL/YR3+GTwpYbM3rc4vZQZVcemo4r2g/FHPFGvSDvi+lCr+h9+CYF2BY9jQD8VjVu zdm+kfZFPuuJulgVob4oV0mwzmzUhCHyOJq3pYXR5eyEH1cZ4ugLLzOTLnz11jHfwjGNRu Hwv2wzeTJv82OQeoERdlWCeInR/CV4w= ARC-Authentication-Results: i=1; imf04.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=FE7aXVZP; spf=pass (imf04.hostedemail.com: domain of ljs@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=ljs@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1785997581; h=from:from:sender: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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=AMdisCQV5YYFAzlzsAkCnp6p2kMaT/VUoOBS5G94/LQ=; b=tl1U9F2Fq3Qtbc2NNKv2orrZNZUkT+7eiPej4OPhF/oPr+1ARXUsHq125Hrvf4DIuUoWN0 lOPiUM9jk0Ypsnj/n70TegRZe6NRDNVd+eUwU5JwVHRJqm2GFU/bmaEZ+wV+jhLKYiMS0F RWdmVrtYktVM/qDz4wlPKp2c59s1FiQ= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 8D2CD60A80; Thu, 6 Aug 2026 06:26:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5D8611F000E9; Thu, 6 Aug 2026 06:26:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785997580; bh=AMdisCQV5YYFAzlzsAkCnp6p2kMaT/VUoOBS5G94/LQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=FE7aXVZPB4G6U2Y7JkMeL/mN8FH3Ijh6cd+5ABNFV+BP4TG9TufITG1o+qAi95lDk +R/pgFriNK1dXJPiiKeuroehJ9XyigZkAPI+xdkHrN6+c237fuC8AdWTLa11vf6jCE hmgiVy82x2T+eyWuYT4i9FH3GuLa1HUKEnzVZjcFkgYZ5bwMRHegjfzKlnhZMkphPR QVFQ5e8WAmOZLsyk99bN6VhBE/fpGZrILyI0cfjyvDpQa34F0MnIoPHknQ5zafp24R htqvGNIjOIMvnDqrpAgucDCpZlo6DMz8JLWjx+W8RbG4Po8ycFoHzAh95sef0qZiyc rJ12229o+LrWw== Date: Thu, 6 Aug 2026 07:25:57 +0100 From: "Lorenzo Stoakes (ARM)" To: Mathieu Desnoyers Cc: Andrew Morton , linux-kernel@vger.kernel.org, "Paul E. McKenney" , Steven Rostedt , Masami Hiramatsu , Dennis Zhou , Tejun Heo , Christoph Lameter , Martin Liu , David Rientjes , christian.koenig@amd.com, Shakeel Butt , SeongJae Park , Michal Hocko , Johannes Weiner , Sweet Tea Dorminy , "Liam R . Howlett" , Mike Rapoport , Suren Baghdasaryan , Vlastimil Babka , Christian Brauner , Wei Yang , David Hildenbrand , Miaohe Lin , Al Viro , Yu Zhao , Roman Gushchin , Mateusz Guzik , Matthew Wilcox , Baolin Wang , Aboorva Devarajan , David Carlier , Josh Law , linux-mm Subject: Re: [PATCH v20 0/6] Hierarchical Percpu Counters for RSS Message-ID: References: <20260707131544.75906-1-mathieu.desnoyers@efficios.com> <0d454717-be7c-47c3-bd5e-2ad304c3423e@efficios.com> <10ca9ff9-428f-49c0-92af-698fd5bea3a3@efficios.com> <20260805115738.5d74e7f41c6f02cc5fd4791e@linux-foundation.org> <0393072a-3950-461b-929e-154001ea4595@efficios.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0393072a-3950-461b-929e-154001ea4595@efficios.com> X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 68DE640008 X-Stat-Signature: 66yr4o865yoyyg6nty4u78456xp8efac X-Rspam-User: X-HE-Tag: 1785997581-395987 X-HE-Meta: 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 FI/5Gid4 nexu7wzh6fDQIb30wek8mwRNc3KXlaT7J4JREaSI5mRs+0fEmc9gDQ1EgW2Bk0/H6cxG69gTjUerKlGggdYqffFgur9fc/lTdfZnU+gPKEp2xraaYkVe0Nmdp8fyYoguv5LhJ6RCq+prwTxqwx79B+4sJZXz6+4HYX3PKb0Txu2LuhedH/7f+2C+kAQJSQodAD7BninWao997v9T1oI2By/wbrYEIDHGg7Me1lQ/o7hNHyH7RZwFAmUTJBi7jUBIEnxtbsgaIeWvm4A+bs9jJUY6HYlNrm4V97NUZLG/7/xOdYz4o1YLTCncCTx6JSnO3NQi8cISnbiOiYK7zStKNa0SuNhrAyPpO9/ezzf7H638TcfOwDOZlfNxb3wvZY7xMP2mI Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, Aug 05, 2026 at 03:03:39PM -0400, Mathieu Desnoyers wrote: > On 2026-08-05 14:57, Andrew Morton wrote: > > On Wed, 5 Aug 2026 14:37:08 -0400 Mathieu Desnoyers wrote: > > > > > On 2026-07-23 13:53, Mathieu Desnoyers wrote: > > > > On 2026-07-07 09:15, Mathieu Desnoyers wrote: > > > > > Hi Andrew, > > > > > > > > > > Here is the hierarchical percpu counters series rebased on top of > > > > > v7.2-rc2. It includes small bootup fixes which were needed to fix > > > > > bootup sequence on specific architectures, and a rename of the > > > > > test config option to include "KUNIT_". > > > > > > > > > > This aims at replacing the prior version of the series you had > > > > > in mm. > > > > > > > > > > As a reminder, the goal here is to provide more precise RSS counters > > > > > through /proc. > > > > > > > > Hello, > > > > > > > > Just a gentle ping for feedback whenever it's convenient. > > > > > > Hi Andrew, > > > > > > Can you pick this up after the upcoming merge window ? > > > > Resending after -rc1 would be appropriate. > > Will do, thanks! > > > > > > That's of course assuming this is solving an issue which is > > > still relevant. > > > > > > If there is no interest in solving this issue anymore, kindly > > > let me know and I'll drop this series. > > > > This was 1000-2000 patches ago so I've forgotten what the issue was! > > Please ensure that changelogging describes the issue in glorious > > detail and I'm sure it'll all come back. > > Certainly. For the immediate records, the issue addressed by this series > is RSS stats inaccuracy when reading /proc files on large SMP boxes. It > gets increasingly worse for long-lifetime processes which jump around > various cores while allocating/freeing memory over their lifetime. > > And once we get this in, it would be relevant to use this infrastructure > to address the tail latency of memcg oom killer, which AFAIU is now a > scan in the order of num_possible_cpus * nb processes. Although not so > bad when the OOM killer fires due to a machine memory use ballooning out > of proportions, it's rather inconvenient to cause large latencies when > it's used to apply the mem cgroup limits, which is a rather more common > routine scenario nowadays. Perhaps Shakeel might have an interest from the memcg side here? :) Also similarly Johannes and Michal/Roman too perhaps? > > Thanks, > > Mathieu > > -- > Mathieu Desnoyers > EfficiOS Inc. > https://www.efficios.com -- Cheers, Lorenzo