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 0E5D2C3DA49 for ; Tue, 30 Jul 2024 17:18:35 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 2A7366B007B; Tue, 30 Jul 2024 13:18:35 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 257CD6B0082; Tue, 30 Jul 2024 13:18:35 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 11F476B0083; Tue, 30 Jul 2024 13:18:35 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id E84AE6B007B for ; Tue, 30 Jul 2024 13:18:34 -0400 (EDT) Received: from smtpin02.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 775841A03EF for ; Tue, 30 Jul 2024 17:18:34 +0000 (UTC) X-FDA: 82397078148.02.9E25210 Received: from mail-ej1-f53.google.com (mail-ej1-f53.google.com [209.85.218.53]) by imf07.hostedemail.com (Postfix) with ESMTP id A644E4000F for ; Tue, 30 Jul 2024 17:18:32 +0000 (UTC) Authentication-Results: imf07.hostedemail.com; dkim=pass header.d=google.com header.s=20230601 header.b=23oYCCH4; spf=pass (imf07.hostedemail.com: domain of yosryahmed@google.com designates 209.85.218.53 as permitted sender) smtp.mailfrom=yosryahmed@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=1722359908; 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=NSwh2S4jFZUNLW279mrTn3SdwO4l4yQsEMBUgQrDYbk=; b=cHj3lJxC+s1jdd0HSKKlOhdU4oaNv/rNSMsWBxRdFPpRPgALo/RZfkg0S4vQUA303dKh3G +Jl80A7bax+QCvJgUs6zu20urRKhwrE3wqbga5eO49ueqOlbEAiwctj0bBryiERqrdRE9j JWDmsbCwWW8zao6UbVPgel2hFtFf2/4= ARC-Authentication-Results: i=1; imf07.hostedemail.com; dkim=pass header.d=google.com header.s=20230601 header.b=23oYCCH4; spf=pass (imf07.hostedemail.com: domain of yosryahmed@google.com designates 209.85.218.53 as permitted sender) smtp.mailfrom=yosryahmed@google.com; dmarc=pass (policy=reject) header.from=google.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1722359908; a=rsa-sha256; cv=none; b=GwNloGqeEDLk+9xO7ovPLyLxnfqXjsJFvsjWUzBsV+xtECPks8xxXPtzrZ+WTxInkI6OVf Vlp+ONbWzZ9nRJ6ZtbzcSoQZaNFQm3WQif6vaJJDPXkaswc5XNN5rCL5QV3nmsI1SmSWIO oWiv/LVxulpEo5CjwaRAili7n24SEyQ= Received: by mail-ej1-f53.google.com with SMTP id a640c23a62f3a-a7a9e25008aso626633466b.0 for ; Tue, 30 Jul 2024 10:18:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1722359911; x=1722964711; 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=NSwh2S4jFZUNLW279mrTn3SdwO4l4yQsEMBUgQrDYbk=; b=23oYCCH4h2nxGiQMZH+egjez8VmAcJFs7vdxFh2BSiw+GmliVP1OTmTVcHuxiW8qWy T6Dn4uUEH1EH2vhBIwlCnzvsy4xgSOvuzw7XQo9aTGcGc7JtVq19l06IAgO8S3wlQku4 G4gvYYfaTLCO+h1JIjwYVa1ZMvogc8FxmnUIqiU917T1r8FO5XUTxdEalEzhaOxrPexe Gys86eKqmgMtZzcslosbkAFFE4k2It6pjfQXg1JezVqgoZDGx5AArrFIdUfMgSkL6aY7 brVZEYiHkoIB89Tkgtob1yiCRlQqD55DmQFoCt0IR5sbLXiGJ4YqZFv5LL4MsWM3HuRh c78g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1722359911; x=1722964711; 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=NSwh2S4jFZUNLW279mrTn3SdwO4l4yQsEMBUgQrDYbk=; b=ee08wFmL0+3+NhGrhUwdUgevhPnhd/oP2RQ985hYNqO9roFUOcSicaYV8jGoSQovhb HChE1vS9JA3GAD0eLFp9LpMBh0Huz/j8JwoSN/H8fu2FQQ/t1p0MVcmIBEnKHcYvMl3e 37x2RYL1FWSxdtD7hcpPqu7R7iTA1vU3L1Holfxw9TNsfRQMJt7gQDA+uhi8cK/S5mT/ LI7pRQ/sTHbS1g21kUalDFpTqkKJRW15qefbrEf67UwHUO2+r8w7jqb0JE+C/5MKGzmb 3WEdbt09DsWEQp37Mv7On+/gRCdq/wJo09XUIKphOkH4N2oUAyWHp5tux9bmeoFUHiv+ JFMQ== X-Forwarded-Encrypted: i=1; AJvYcCXVqcYNOaZvvAPG6kGN4HO5DG6aDAcA7RV9mYfljZ3jOEerQaD5tTK1H/VCPbdxNo+q7IQwqFpDcd2d8SuqjvMOkAk= X-Gm-Message-State: AOJu0YwGIrGMg2BPjBKz1LmW4Ycko9dHhhPfOUdSj4LKBnFcceWOsezb Cvv7Oyb7NsAAHWi1NKjD+fIGYaS0CbTW3DCOthqXIYa8wxerx4SL56kq8xVjB/ak0Hx642judxT yY95BTS3Tw6ADAC+Ag3I9U4H5lRM/tBcHT8aF X-Google-Smtp-Source: AGHT+IH48rycmcn5SYzBW5ZC8UbZoUnMTbOHz0noIuwNpgbbja3UlcoUmoGDSVmhxt7iRguQJ6tBZo30R0axzOWbm+Y= X-Received: by 2002:a17:906:c10f:b0:a77:d441:c6f1 with SMTP id a640c23a62f3a-a7d400af7f6mr804585366b.33.1722359910408; Tue, 30 Jul 2024 10:18:30 -0700 (PDT) MIME-Version: 1.0 References: <20240730150158.832783-1-pasha.tatashin@soleen.com> <20240730150158.832783-2-pasha.tatashin@soleen.com> In-Reply-To: <20240730150158.832783-2-pasha.tatashin@soleen.com> From: Yosry Ahmed Date: Tue, 30 Jul 2024 10:17:54 -0700 Message-ID: Subject: Re: [PATCH v6 1/3] memcg: increase the valid index range for memcg stats To: Pasha Tatashin Cc: akpm@linux-foundation.org, jpoimboe@kernel.org, kent.overstreet@linux.dev, peterz@infradead.org, nphamcs@gmail.com, cerasuolodomenico@gmail.com, surenb@google.com, lizhijian@fujitsu.com, willy@infradead.org, shakeel.butt@linux.dev, vbabka@suse.cz, ziy@nvidia.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspam-User: X-Stat-Signature: uzdio4dxpei7cirsbken4mc9d3xu6arw X-Rspamd-Queue-Id: A644E4000F X-Rspamd-Server: rspam11 X-HE-Tag: 1722359912-407994 X-HE-Meta: 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 kGRW8N7e 4BQLqVyPGu43snJ4YPQm/MpV5/MPwfSNN8ySvyTWf0KAbjR4A4Axy+DFC5poP2namAnCS/MxtWmPYiuU2uyqlfj4qmDbP3p9UOpDR0jk8za1FIf2zzeUl9q1JNyaJ6yojpWMlli7tMaLjlwAt6PL7RDYMEktQk5tV2Twj8u8eZom88lrlwLRPzEAYDpLCOD+2VGq+9ijCmQgb7spIn1f2ONdN2Ab/NhT75P+9pm0hKEULDKSPmT2WNgXA1AeBvy3alb7D X-Bogosity: Ham, tests=bogofilter, spamicity=0.109848, 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 Tue, Jul 30, 2024 at 8:02=E2=80=AFAM Pasha Tatashin wrote: > > From: Shakeel Butt > > At the moment the valid index for the indirection tables for memcg stats > and events is < S8_MAX. These indirection tables are used in performance > critical codepaths. With the latest addition to the vm_events, the > NR_VM_EVENT_ITEMS has gone over S8_MAX. One way to resolve is to > increase the entry size of the indirection table from int8_t to int16_t > but this will increase the potential number of cachelines needed to > access the indirection table. > > This patch took a different approach and make the valid index < U8_MAX. > In this way the size of the indirection tables will remain same and we > only need to invalid index check from less than 0 to equal to U8_MAX. > In this approach we have also removed a subtraction from the performance > critical codepaths. > > Signed-off-by: Shakeel Butt > Co-developed-by: Pasha Tatashin > Signed-off-by: Pasha Tatashin Reviewed-by: Yosry Ahmed