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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E8CEAC433EF for ; Wed, 27 Oct 2021 18:23:39 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 7863660F38 for ; Wed, 27 Oct 2021 18:23:39 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 7863660F38 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=soleen.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id 1A3DA6B0071; Wed, 27 Oct 2021 14:23:39 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 17AE96B0073; Wed, 27 Oct 2021 14:23:39 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 01BE86B0074; Wed, 27 Oct 2021 14:23:38 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0074.hostedemail.com [216.40.44.74]) by kanga.kvack.org (Postfix) with ESMTP id D24346B0071 for ; Wed, 27 Oct 2021 14:23:38 -0400 (EDT) Received: from smtpin31.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 65889348C0 for ; Wed, 27 Oct 2021 18:23:38 +0000 (UTC) X-FDA: 78743040516.31.8C965C4 Received: from mail-lf1-f53.google.com (mail-lf1-f53.google.com [209.85.167.53]) by imf10.hostedemail.com (Postfix) with ESMTP id 3E6F260019A1 for ; Wed, 27 Oct 2021 18:23:30 +0000 (UTC) Received: by mail-lf1-f53.google.com with SMTP id p16so8083338lfa.2 for ; Wed, 27 Oct 2021 11:23:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=soleen.com; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=jm/RSf4rCAITEo2BV23aNePeo8qwzmc9rjVyo//Sm2w=; b=DE53XnOsp2UZoHcQaGjN87P4NcbSE8qj1rBVRDhKYNzC81Sy+TaGIz6zgbRDa/vuDJ KNWTN52x9VpgsgZRqOL49qcoT+nz81r0kHjinwiCaa6y+XsG7oaM0JEJJuqnooFAR5rx khuxM+qC3sGdFQGJ0MWfcvEMyCP8aVzIrasBq9RSYVlPsbVMAgYtQJKAQz8niwOYnkmU +q7PL8YBOW6lnqyHqFrFjcNLK/ZstGzw28n466sjq53t8f8HTWiQnObvcohU2V9fhCSA dvMuInKsZVBJ2FFVNuh2nesWSw4OQtn5G3i6ZPX3fLEMSpntmgamQnPW3jdgETvX10Np pNUw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=jm/RSf4rCAITEo2BV23aNePeo8qwzmc9rjVyo//Sm2w=; b=TiFc7EDqAhYxXoQyj2tFJDSdog92q1C6cpW3DSjMPM3RkNWDMOGjhBghTT8FY9O73H yMbYDxJ1LI+embHXEJQIK3BsDlKE5zOciAvwDuSy+EhtGdm9YcZmlQwej9vOsUr/Fuug x9BbKMK1cSWHk2zKwLRC/0axOjeYKvuSMsLZcCMqyBRv6kz5PYUrO9+8fuPSJMmKOKNe nyqPhOgMmjapWYHlZYmNGu0RwCwGx+Sl4u74ucmWSiblSjhRjrSVg5do5oWvVN6eKbrz VxhKufEOYc1ElDlisSRvSkSPQauxE1gsYSg4zW1sKGqERqo3P49wGUW8HNpApspcHhyi 53dw== X-Gm-Message-State: AOAM533NO2eo87gEpn930eKyGsudfmSqEAI+rK5n/c84EX9gpvXHWdix KRDg3U8FP64wmmI/CV/8904Zx+3ZIUgex5jZo/57Iw== X-Google-Smtp-Source: ABdhPJzF9GpWULmhvrOQLqZG1vjigpdCyvN06x5InpHqzQbrjC7IEgs8r9nSKwjIi/xqAB5PqByC37tkZTYQpF/rWLE= X-Received: by 2002:a05:6512:1046:: with SMTP id c6mr12998783lfb.475.1635359016292; Wed, 27 Oct 2021 11:23:36 -0700 (PDT) MIME-Version: 1.0 References: <20211026173822.502506-1-pasha.tatashin@soleen.com> <20211026173822.502506-2-pasha.tatashin@soleen.com> In-Reply-To: From: Pasha Tatashin Date: Wed, 27 Oct 2021 14:22:58 -0400 Message-ID: Subject: Re: [RFC 1/8] mm: add overflow and underflow checks for page->_refcount To: Matthew Wilcox Cc: LKML , linux-mm , linux-m68k@lists.linux-m68k.org, Anshuman Khandual , Andrew Morton , william.kucharski@oracle.com, Mike Kravetz , Vlastimil Babka , Geert Uytterhoeven , schmitzmic@gmail.com, Steven Rostedt , Ingo Molnar , Johannes Weiner , Roman Gushchin , Muchun Song , weixugc@google.com, Greg Thelen Content-Type: text/plain; charset="UTF-8" X-Stat-Signature: 7b653p41minopiegrnd63h66t1uz94kn X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 3E6F260019A1 Authentication-Results: imf10.hostedemail.com; dkim=pass header.d=soleen.com header.s=google header.b=DE53XnOs; dmarc=none; spf=pass (imf10.hostedemail.com: domain of pasha.tatashin@soleen.com designates 209.85.167.53 as permitted sender) smtp.mailfrom=pasha.tatashin@soleen.com X-HE-Tag: 1635359010-300375 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, Oct 26, 2021 at 11:05 PM Matthew Wilcox wrote: > > On Tue, Oct 26, 2021 at 09:21:29PM -0400, Pasha Tatashin wrote: > > I think we can do that by using: > > atomic_fetch_*() and check for overflow/underflow after operation. I > > will send the updated series soon. > > Please include performance measurements. You're adding code to some hot > paths. I will do boot performance tests to ensure we do not regress initializing "struct pages" on larger machines. Do you have a suggestion for another perf test? Thanks, Pasha