From patchwork Mon Dec 20 21:58:22 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: andrey.konovalov@linux.dev X-Patchwork-Id: 12688699 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 A8DB6C433EF for ; Mon, 20 Dec 2021 21:59:16 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 2EA5D6B0087; Mon, 20 Dec 2021 16:59:16 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 272696B0088; Mon, 20 Dec 2021 16:59:16 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 113B56B0089; Mon, 20 Dec 2021 16:59:16 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0020.hostedemail.com [216.40.44.20]) by kanga.kvack.org (Postfix) with ESMTP id F08526B0087 for ; Mon, 20 Dec 2021 16:59:15 -0500 (EST) Received: from smtpin21.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id BB516180AF877 for ; Mon, 20 Dec 2021 21:59:15 +0000 (UTC) X-FDA: 78939539070.21.C455724 Received: from out2.migadu.com (out2.migadu.com [188.165.223.204]) by imf03.hostedemail.com (Postfix) with ESMTP id 2F98820032 for ; Mon, 20 Dec 2021 21:59:15 +0000 (UTC) X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1640037554; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=aF/w+x0GM7OFXEFWoRiyjv8BJ7kPS/Lh2UMzxPnFpS8=; b=n3qgP2Kwql5PJOXWDga39XJfJDwSn5Ws1RXS3NQqtcINXPkTL/dlMfu6/kR0LFjJZkD6aT SGurSZDLBq7aIWTqUvkFMman0cJ55/71E4WMbntko/6xJCNU97aVZnwLSdvbnmUUCIbqQw S2eLsStCNBajcbuKYEIH2H/w8JgaAfk= From: andrey.konovalov@linux.dev To: Marco Elver , Alexander Potapenko , Andrew Morton Cc: Andrey Konovalov , Dmitry Vyukov , Andrey Ryabinin , kasan-dev@googlegroups.com, linux-mm@kvack.org, Vincenzo Frascino , Catalin Marinas , Will Deacon , Mark Rutland , linux-arm-kernel@lists.infradead.org, Peter Collingbourne , Evgenii Stepanov , linux-kernel@vger.kernel.org, Andrey Konovalov Subject: [PATCH mm v4 07/39] mm: clarify __GFP_ZEROTAGS comment Date: Mon, 20 Dec 2021 22:58:22 +0100 Message-Id: <92f3029f3647ab355450ed5c8252bad8cfae1e09.1640036051.git.andreyknvl@google.com> In-Reply-To: References: MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT X-Migadu-Auth-User: linux.dev X-Rspamd-Queue-Id: 2F98820032 X-Stat-Signature: fm68c8gunitk4tewb6pneyhb6tun1z5h Authentication-Results: imf03.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=n3qgP2Kw; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf03.hostedemail.com: domain of andrey.konovalov@linux.dev designates 188.165.223.204 as permitted sender) smtp.mailfrom=andrey.konovalov@linux.dev X-Rspamd-Server: rspam02 X-HE-Tag: 1640037555-455532 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: From: Andrey Konovalov __GFP_ZEROTAGS is intended as an optimization: if memory is zeroed during allocation, it's possible to set memory tags at the same time with little performance impact. Clarify this intention of __GFP_ZEROTAGS in the comment. Signed-off-by: Andrey Konovalov Reviewed-by: Alexander Potapenko --- include/linux/gfp.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/include/linux/gfp.h b/include/linux/gfp.h index 0b2d2a636164..d6a184523ca2 100644 --- a/include/linux/gfp.h +++ b/include/linux/gfp.h @@ -228,8 +228,8 @@ struct vm_area_struct; * * %__GFP_ZERO returns a zeroed page on success. * - * %__GFP_ZEROTAGS returns a page with zeroed memory tags on success, if - * __GFP_ZERO is set. + * %__GFP_ZEROTAGS zeroes memory tags at allocation time if the memory itself + * is being zeroed (either via __GFP_ZERO or via init_on_alloc). * * %__GFP_SKIP_KASAN_POISON returns a page which does not need to be poisoned * on deallocation. Typically used for userspace pages. Currently only has an