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 ADA2DCA0FEC for ; Fri, 1 Sep 2023 18:32:42 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id A54FE8D0025; Fri, 1 Sep 2023 14:32:41 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id A052D8D0002; Fri, 1 Sep 2023 14:32:41 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 8CDA18D0025; Fri, 1 Sep 2023 14:32:41 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id 7AD0E8D0002 for ; Fri, 1 Sep 2023 14:32:41 -0400 (EDT) Received: from smtpin27.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 3E703C036A for ; Fri, 1 Sep 2023 18:32:41 +0000 (UTC) X-FDA: 81188874522.27.440AA43 Received: from mail-pl1-f178.google.com (mail-pl1-f178.google.com [209.85.214.178]) by imf24.hostedemail.com (Postfix) with ESMTP id 6A110180015 for ; Fri, 1 Sep 2023 18:32:39 +0000 (UTC) Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=chromium.org header.s=google header.b=EgNT1w4y; dmarc=pass (policy=none) header.from=chromium.org; spf=pass (imf24.hostedemail.com: domain of keescook@chromium.org designates 209.85.214.178 as permitted sender) smtp.mailfrom=keescook@chromium.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1693593159; 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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=z6OX4ESsTLl6ApuI6FDV4HSspv8mn63QqTxuR45w8VU=; b=OThUzXv4MN8OCGlaVXRYXNc+elG/azMXVUrk0NJtRdasEtWDGJrof/zkdfJ1kI9snKT0uD CSNRqT65A1VOz42VqvuZuxNySQmW3vwbrGi6oLCpKy5gggmxoZlxia+PkJ9dAlSrJj9mgJ /iQzfxvEsVcLL+A9h2xyg+JZhIMqUqM= ARC-Authentication-Results: i=1; imf24.hostedemail.com; dkim=pass header.d=chromium.org header.s=google header.b=EgNT1w4y; dmarc=pass (policy=none) header.from=chromium.org; spf=pass (imf24.hostedemail.com: domain of keescook@chromium.org designates 209.85.214.178 as permitted sender) smtp.mailfrom=keescook@chromium.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1693593159; a=rsa-sha256; cv=none; b=s8OljDMbSsW3P8s4tHiPYUMfW1MP43QnCsZtc9Yg3qcp9zuQYXh1TAAo8T5uPqVah/LoJ6 RCGQggZoCb5zlkOpvoHp8Bfa4Bzna6YkT4YpuI7a+DlrNjoa/GeC7DQ19D/CKL+zS3jf71 prfFJCj7esDJU5723fY64xX2oRIpGdQ= Received: by mail-pl1-f178.google.com with SMTP id d9443c01a7336-1c1f8aaab9aso18299705ad.1 for ; Fri, 01 Sep 2023 11:32:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; t=1693593158; x=1694197958; darn=kvack.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=z6OX4ESsTLl6ApuI6FDV4HSspv8mn63QqTxuR45w8VU=; b=EgNT1w4ymo+OG4Q2oB3ni+ynIoxKAu7FX6tUQAAClW/zgZzJnFv3sTMLsV9NDg3c2e vLdEbEYR7FdvowemdnUX584Nn75U8GyGM5cclTAn2eHvbj1XVTbNWmpiIEiRThPn0epb FKA1EUVfZ61aK+segt+cpUgq7dM8n/4z0Z/Po= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1693593158; x=1694197958; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=z6OX4ESsTLl6ApuI6FDV4HSspv8mn63QqTxuR45w8VU=; b=DAZ8ULDssUxwsQA2D0VMB/0iilstMEYszqfRLHJVKvVOSnQKAX8X3/F8gaTjDen1o4 3SRQAzjgW1WzxwNgJ5iwGb5e6RTM6gHI13D0BTWmoQGXpJBaY7snNm/o+kN3XtUuCA1U vL7FcieIKwFblJb08q76TWQabl38/70x2kJPcHXy1H+E7LHgoLusSd1oiIgR1d+lqHSC FfN4IflElg8He0j7D9Cr3clMNP9OeIWxHFP9W/eGKkbtIibLd4X5ETOmhki1zJrk82MZ fj87zHMJukYHHXEhaO69cT8wSqaSPcQk2KjH3AJ1xM3LYrJpbkDEhXEwEKVKBZWVooKY 3XyQ== X-Gm-Message-State: AOJu0YxE0zWr6dJdZKh7vWEB9hgUioDzVTWJbr0J1yZOXwQ3U9++mQTH aM++qWRStGvkQs8QLt7rmMFU8Q== X-Google-Smtp-Source: AGHT+IEXedxDyhssdkjDhR0kl/szUvNh9UK8tCVEFt6vr38Ypb8iBBJ2vnd51/Nd8wNZ6wSMkn1OQg== X-Received: by 2002:a17:903:11cc:b0:1be:f53c:7d1d with SMTP id q12-20020a17090311cc00b001bef53c7d1dmr4496217plh.23.1693593158093; Fri, 01 Sep 2023 11:32:38 -0700 (PDT) Received: from www.outflux.net (198-0-35-241-static.hfc.comcastbusiness.net. [198.0.35.241]) by smtp.gmail.com with ESMTPSA id q14-20020a170902788e00b001bc930d4517sm3284865pll.42.2023.09.01.11.32.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 01 Sep 2023 11:32:37 -0700 (PDT) Date: Fri, 1 Sep 2023 11:32:37 -0700 From: Kees Cook To: Alexander Potapenko Cc: Zhaoyang Huang , Matthew Wilcox , "zhaoyang.huang" , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, ke.wang@unisoc.com, Marco Elver , Dmitry Vyukov , Dave Hansen , Michal Hocko , Eric Biggers , Mateusz Guzik , Linus Torvalds , Al Viro Subject: Re: [PATCH] mm: make __GFP_SKIP_ZERO visible to skip zero operation Message-ID: <202309011130.7543E1DC9D@keescook> References: <20230831105252.1385911-1-zhaoyang.huang@unisoc.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Queue-Id: 6A110180015 X-Rspam-User: X-Rspamd-Server: rspam04 X-Stat-Signature: 6tb33nd4u7yz7of9mdfyzpkr84z81r55 X-HE-Tag: 1693593159-275093 X-HE-Meta: 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 il9pvZ7a fZPD2vUitwdLqx3ZPgWDEGLQ/H4tnc1pDaEADPrBqsfPnO1TfmOwcmXtmxkiKGrzNzS80kqKGFmMdwP18FI7xoMuvQ0GZZbvmV2j+0BjZzuRB9j3Yl9tDHff6am5MkFtKsMq5+euNwNMdorrBDDVcgOWSg7OSkEQ3bPk/0WR7GWDQj74mbZy6Bg9lXyfwB7kFTiMdA84ys4RVXoX3I+nqF2fpvHl9R91acMG0PDJ0qvf4eUhlT+RKHyTir2oCvMX5W5E0n+z73Bq5Mn1OD/XenSx1xOMdyaX1yq/n4LsJKiqZWWEVgr6SKkEBXs1HOulJaAZ/a9Gg+xFTlKOTBjYeT0d22mDeleUs/RAIlK91jmbEzUFyg1pQa053NKDuufXIol4prZmQk0GdQMd9UGev0JCyd7Sip/gdNri9sclBVRly2WU= 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 Fri, Sep 01, 2023 at 02:55:17PM +0200, Alexander Potapenko wrote: > A draft implementation at > https://github.com/ramosian-glider/linux/commit/00791be14eb1113eae615c74b652f94b5cc3c336 > (which probably does not apply anymore) may give some insight into how > this is supposed to work. > There's plenty of room for bikeshedding here (does the command-line > flag opt-in or opt-out? should we use function names instead of some > "keys"? can we allow overriding every allocation site without the need > for alloc_pages_uninit()?), but if the overall scheme is viable I can > probably proceed with an RFC. This is my preferred direction to go with this idea (though I agree some internals could be partially whitelisted: the "dup" functions need to wipe the trailing rounded-up bucket size bytes still). -- Kees Cook