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]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7FB29C4345F for ; Mon, 29 Apr 2024 22:23:43 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id E6B406B0085; Mon, 29 Apr 2024 18:23:42 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id E1B636B0087; Mon, 29 Apr 2024 18:23:42 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D099F6B0088; Mon, 29 Apr 2024 18:23:42 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id B3F6B6B0085 for ; Mon, 29 Apr 2024 18:23:42 -0400 (EDT) Received: from smtpin06.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 32888A110B for ; Mon, 29 Apr 2024 22:23:42 +0000 (UTC) X-FDA: 82063997484.06.1FAC797 Received: from mail-yb1-f182.google.com (mail-yb1-f182.google.com [209.85.219.182]) by imf21.hostedemail.com (Postfix) with ESMTP id 705381C000D for ; Mon, 29 Apr 2024 22:23:40 +0000 (UTC) Authentication-Results: imf21.hostedemail.com; dkim=pass header.d=google.com header.s=20230601 header.b="zeRLS/Xc"; spf=pass (imf21.hostedemail.com: domain of tjmercier@google.com designates 209.85.219.182 as permitted sender) smtp.mailfrom=tjmercier@google.com; dmarc=pass (policy=reject) header.from=google.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1714429420; 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:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=OGlufsSMUfGTy8V2I8bIM/xvglG1OuNLwieN2n+XFOw=; b=8Zr1HGnK0dEgx7kbndJ5+18fZwgIjQAmpzMLMxOXGm2gjUc328+K2iLCfyzX+WNWY3LcCc VxVco3DR4UFjeb8az7K1jzDYb+VkHd7sFWNt0ajQuMgOOgaOCWNLcMq3LmPSGTnlxnPsBa OQqhjUg3Jxd3LXbffHY9WQWEbgafgFc= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1714429420; a=rsa-sha256; cv=none; b=HATiqQZTPgCWmoveSvPYMt0/f0bc/S+4UN5x+EfdzFr17+LC3QswjbrLZFfgwFEuPTDJAV LK4H10oEczE07994j07zc85OVRmIfM6T9RIhlJ8UO503wLKg/CR/EOldbfohOfHXcVjJDl oqe4CKchoiFPloFtoHdqrfSZ9ea9Qyc= ARC-Authentication-Results: i=1; imf21.hostedemail.com; dkim=pass header.d=google.com header.s=20230601 header.b="zeRLS/Xc"; spf=pass (imf21.hostedemail.com: domain of tjmercier@google.com designates 209.85.219.182 as permitted sender) smtp.mailfrom=tjmercier@google.com; dmarc=pass (policy=reject) header.from=google.com Received: by mail-yb1-f182.google.com with SMTP id 3f1490d57ef6-de462979e00so5648173276.3 for ; Mon, 29 Apr 2024 15:23:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1714429419; x=1715034219; darn=kvack.org; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=OGlufsSMUfGTy8V2I8bIM/xvglG1OuNLwieN2n+XFOw=; b=zeRLS/XcxhHuknXQ+Wri4FfCZrxwG0poyuL5o5gmMqjTfeeaeXkEn+UBg6IWnNqDvq t+gIsnO+WY/qJd4GL9SA5bz5Nn9CX37MCwkTUil8r9WoeMjJiHZ02W4c7AbaFPzxyTaX FtU8uyKHC1jHiHl7cfXvLSXXq1R2t80GYmMgSERrJYGE1VNrEC8dqd93aQUwxqA9/mm4 KlvkYn0QLZmfayVqX0h6GpDbo0b07Ho08dEOjyAtIy0nm+Evm1s15JRb0S74nyuXg1de 0chNRzrhJNmdsVAdmOm+x9jGp8oa3RgdRLlwUitwOAYaybX7fkHzlDLvrGDj0Kj4LLH8 p1hA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1714429419; x=1715034219; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=OGlufsSMUfGTy8V2I8bIM/xvglG1OuNLwieN2n+XFOw=; b=qjcS1bbrb8AhN/2MMKYtywaYspvwKuUaevwtxK2VGzSJ/NIxa7wE0bPmZkaoGlrjjW 82jt6Q+LEOeMCosClqXod/MLv0EF208DgPaTtGBUkwSA8aCMNl3GEwg5huqnGBz5oYQQ HFacny+uTEaFlIu6kzuHa3MCrNKkMVqkKM7igPAL6Y0zlZBKwVyEx3//9fHIXtr1ufmk 2lfNdslMD+w6+ijqZ4VF3miTgSy28w3es26xx+lFbk6Zlq5OlSQuldhbuCNdvgdDdnSN i3/xVKIk7Qty/fc3fWXxEmr32aPyEsQJR4vobKLSO8BZL2ld0G0Q0717cr79VzZr2YY1 b9lA== X-Forwarded-Encrypted: i=1; AJvYcCUJCpR69gataegbWfKg9zlpDBJG1mRvuyZzS+P6zCnIqnbRusPUggRznPdUSxo+PN0JBf5AHgk0ZSESkF9/m+VGsuA= X-Gm-Message-State: AOJu0Yx0ETv9XDU56qbdGB10NsLlw5s8o3YGE9HEUnPXBvs0EGRs3Cty 6ZTERdb81bXTlbXaBAH50IoxDYwvEuVGKTwHRYAwj/xdLgbNHX/ViGKQZlAMncaPX5u3bQMtGVq lJtiQ92Th+r9PMXdwvfrv43L5Tw7XElUHQIfT X-Google-Smtp-Source: AGHT+IFcZdV4o2I0NUoP3fsMkexjFVz2+gYRb/Ki6ZR5UaWOT+mDGMiynQRMBiBVixthEiWIHr0px9K7N8duA/KrQCI= X-Received: by 2002:a05:6902:160d:b0:de5:5647:c87e with SMTP id bw13-20020a056902160d00b00de55647c87emr14146085ybb.33.1714429419440; Mon, 29 Apr 2024 15:23:39 -0700 (PDT) MIME-Version: 1.0 References: <20240427003733.3898961-1-shakeel.butt@linux.dev> <20240427003733.3898961-4-shakeel.butt@linux.dev> In-Reply-To: From: "T.J. Mercier" Date: Mon, 29 Apr 2024 15:23:28 -0700 Message-ID: Subject: Re: [PATCH v2 3/7] memcg: reduce memory for the lruvec and memcg stats To: Shakeel Butt Cc: Andrew Morton , Johannes Weiner , Michal Hocko , Roman Gushchin , Muchun Song , linux-mm@kvack.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspam-User: X-Stat-Signature: pp83gswfxxm6fdkssx4qhtzx3wdrrkfu X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 705381C000D X-HE-Tag: 1714429420-355702 X-HE-Meta: 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 0fxrg/XA XxVqIjaibuY9/s2VTNXB5NChZJ9QSMM8oArsf+oGMgkgEXtwRebm44SemON4Uv/+GnP+qcEpw3gYH0QgaiyxEszOv0t1L3PtuMsU/EPldJK2Vys4zN7/dSRmGHgYbtmgRbRp1ixNqyZsRz8aLUZBoeZiNs5roeocTMlOmaMQw14VZjPj+7xbAwjMb+CExrmFgFbJWMzhMa6CC8bu9QE4MjM5GhFF1gRdYWPea X-Bogosity: Ham, tests=bogofilter, spamicity=0.020467, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Apr 29, 2024 at 1:13=E2=80=AFPM Shakeel Butt wrote: > > On Mon, Apr 29, 2024 at 10:35:38AM -0700, T.J. Mercier wrote: > > On Fri, Apr 26, 2024 at 5:37=E2=80=AFPM Shakeel Butt wrote: > > > > [...] > > > + > > > +static const unsigned int memcg_stat_items[] =3D { > > > + MEMCG_SWAP, > > > + MEMCG_SOCK, > > > + MEMCG_PERCPU_B, > > > + MEMCG_VMALLOC, > > > + MEMCG_KMEM, > > > + MEMCG_ZSWAP_B, > > > + MEMCG_ZSWAPPED, > > > +}; > > > > Unsigned for these? All the values are positive now, but I don't think > > we'll get a build warning if a negative one ever got added, just a > > crash or corruption. BUG_ON in init_memcg_stats if a > > memcg_stat_items[i] < 0? > > We are depending on NR_VM_NODE_STAT_ITEMS to tell the number of elements > for vmstats. So, I think there is an implicit assumption that there are > no negative enums in enum node_stat_item. So, if we want to verify those > assumptions then we should be adding such warnings/build-bugs in vmstat > first. Ok fair. I guess this if we get C23: enum node_stat_item : unsigned {