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 5FAAB3BB669 for ; Thu, 6 Aug 2026 06:26:20 +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=1785997581; cv=none; b=CnGy2Nu4ZvjzHS8URrs/+kRiLCF0c0pOK6Y/442SheNBzj7Q7lctFzNRtbfYXyfs9URnAZ2Gm3HiLe0Mp2mUsjATrs7X49pIL9XD7Uh91D/PF3Pd2KrQKKBOJ5AU4mLjyrr7cYbEhhmNacVlrLyjJg1PEoEmyzsmJ36VK4fA43Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785997581; c=relaxed/simple; bh=AMdisCQV5YYFAzlzsAkCnp6p2kMaT/VUoOBS5G94/LQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=hGyYiuqVj9Y+KHYOMGQixpmEZHd3p7oZ+y1/veqnmKfZpv6dW3fWssOVVNqRuqy1KGkZkhZ9UIQ7l9qA9dHQgZM1gq2Nkx+1BmJjRIyhymRcJLq0wSL0Nx1pDtTAnp0CLDIrqVxJ57xI6dX7QFyBxG6VgAZMpZfGSYmp1lNfZkE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=FE7aXVZP; 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="FE7aXVZP" 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> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0393072a-3950-461b-929e-154001ea4595@efficios.com> 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