From nobody Sun Feb 8 00:12:19 2026 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 653ABC77B73 for ; Wed, 24 May 2023 18:19:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235841AbjEXSTY (ORCPT ); Wed, 24 May 2023 14:19:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50562 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237231AbjEXSTQ (ORCPT ); Wed, 24 May 2023 14:19:16 -0400 X-Greylist: delayed 62 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Wed, 24 May 2023 11:19:08 PDT Received: from smtp-lb.pixar.com (smtp-lb.pixar.com [138.72.247.109]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 00702E47 for ; Wed, 24 May 2023 11:19:08 -0700 (PDT) DomainKey-Signature: s=emeryville; d=pixar.com; c=nofws; q=dns; h=Authentication-Results:IronPort-SDR:X-PixarMID: X-PixarRecvListener:X-PixarRemoteIP:X-PixarMailFlowPolicy: Received:From:To:Cc:Subject:Date:Message-Id:X-Mailer: MIME-Version:Content-Transfer-Encoding; b=d1j/4YnC+mVvTtW7b3uSZjWpcsNFVh9Y3rggMUxn2rnE5NbtE8FOGnS5 aPNPzIeAjIRempRcFZuZY6VwxgLEE0UnLG3wONdp9wIVUQV58Qc390y6Z UG7OSoYO9ovNreTTkE4Yn7zCEKoFXj8p6aKbh5VVXenaPUz21+C2fWn23 NhWMv71pmHsyius6Tw5G6y4OjhkilIzzXG/REuYzB0Vsq7FBCIqtJTZij lsRG16OuY3JZqKJGyWlEAv52k237aDVlaOU8uDs8ITJegU6U59ZY4y6Hm 41Nj7gYunXZx+ae6iwc7VgeJ0n+HZqjUmw0+bnSQRmas8i61Eap7gxCSy w==; DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=pixar.com; i=@pixar.com; q=dns/txt; s=dkimdefault; t=1684952348; x=1716488348; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=ww88k/sRfXor8CGXgyhHTr6O6My3nfazkW6nHTYMUoE=; b=fHnFefEvF0bbH0frkbR6r20UGIwhKiyLDDc0bDmTswmj6w/g7xK3oJfm dYYVFFuL27hrPFApW6XIJEKFiKwFOHXUMb9iICLgorst7maptfBmNQ5db GuaypsXuO0qkQzGQBZgPpBbS9xMNcqyoTXrjpCMGpJFVoLjmHeS3Tn86H 0DSodqrwtjnqzJpWAUZVJ/PQgU4eXjDkGqFSp7JX5HTqOK/gJstWkEIM/ Lh6XzhLhykRd2sWp7UPmPoJXzM7dIXZRwcb4o5LlysIz6pRCRqT5GE19O 01IFz/s4O+9ecg4dt/ZWg1G+Gh7SC+/LZzFeOUVHKBqkVLCyyuKReXzSF Q==; Authentication-Results: smtp-lb.pixar.com; dkim=none (message not signed) header.i=none IronPort-SDR: Uzb3RSa/vzGo8sU7GYm5MeSjCugi8B7FA1VjUyt3kXYw31N9HCzMXHDZpzskXLstM8+drU6fYk jblJdBUQLRRw== X-PixarMID: 33424248 X-PixarRecvListener: OutboundMail X-PixarRemoteIP: 138.72.53.70 X-PixarMailFlowPolicy: $RELAYED Received: by belboz.pixar.com (Postfix, from userid 1690) id 63EC8601DB34; Wed, 24 May 2023 11:18:04 -0700 (PDT) From: "Lars R. Damerow" To: mhocko@kernel.org, roman.gushchin@linux.dev, shakeelb@google.com Cc: tj@kernel.org, lizefan.x@bytedance.com, hannes@cmpxchg.org, corbet@lwn.net, muchun.song@linux.dev, akpm@linux-foundation.org, cgroups@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, lars@pixar.com Subject: [PATCH] mm/memcontrol: export memcg.swap watermark via sysfs for v2 memcg Date: Wed, 24 May 2023 11:17:33 -0700 Message-Id: <20230524181734.125696-1-lars@pixar.com> X-Mailer: git-send-email 2.39.2 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" This patch is similar to commit 8e20d4b33266 ("mm/memcontrol: export memcg->watermark via sysfs for v2 memcg"), but exports the swap counter's watermark. We allocate jobs to our compute farm using heuristics determined by memory and swap usage from previous jobs. Tracking the peak swap usage for new jobs is important for determining when jobs are exceeding their expected bounds, or when our baseline metrics are getting outdated. Our toolset was written to use the "memory.memsw.max_usage_in_bytes" file in cgroups v1, and altering it to poll cgroups v2's "memory.swap.current" would give less accurate results as well as add complication to the code. Having this watermark exposed in sysfs is much preferred. Signed-off-by: Lars R. Damerow Acked-by: Johannes Weiner --- Documentation/admin-guide/cgroup-v2.rst | 7 +++++++ mm/memcontrol.c | 13 +++++++++++++ 2 files changed, 20 insertions(+) diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-= guide/cgroup-v2.rst index f67c0829350b..1ffe019483ac 100644 --- a/Documentation/admin-guide/cgroup-v2.rst +++ b/Documentation/admin-guide/cgroup-v2.rst @@ -1582,6 +1582,13 @@ PAGE_SIZE multiple when read back. =20 Healthy workloads are not expected to reach this limit. =20 + memory.swap.peak + A read-only single value file which exists on non-root + cgroups. + + The max swap usage recorded for the cgroup and its + descendants since the creation of the cgroup. + memory.swap.max A read-write single value file which exists on non-root cgroups. The default is "max". diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 4b27e245a055..1862fee15274 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -7656,6 +7656,14 @@ static u64 swap_current_read(struct cgroup_subsys_st= ate *css, return (u64)page_counter_read(&memcg->swap) * PAGE_SIZE; } =20 +static u64 swap_peak_read(struct cgroup_subsys_state *css, + struct cftype *cft) +{ + struct mem_cgroup *memcg =3D mem_cgroup_from_css(css); + + return (u64)memcg->swap.watermark * PAGE_SIZE; +} + static int swap_high_show(struct seq_file *m, void *v) { return seq_puts_memcg_tunable(m, @@ -7734,6 +7742,11 @@ static struct cftype swap_files[] =3D { .seq_show =3D swap_max_show, .write =3D swap_max_write, }, + { + .name =3D "swap.peak", + .flags =3D CFTYPE_NOT_ON_ROOT, + .read_u64 =3D swap_peak_read, + }, { .name =3D "swap.events", .flags =3D CFTYPE_NOT_ON_ROOT, base-commit: 9d646009f65d62d32815f376465a3b92d8d9b046 --=20 2.39.2