From patchwork Tue Nov 30 21:41:28 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: 12648211 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 8E7E1C433FE for ; Tue, 30 Nov 2021 21:44:07 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 64C4A6B007E; Tue, 30 Nov 2021 16:41:50 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 5FA2B6B0080; Tue, 30 Nov 2021 16:41:50 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 474B46B0081; Tue, 30 Nov 2021 16:41:50 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0202.hostedemail.com [216.40.44.202]) by kanga.kvack.org (Postfix) with ESMTP id 322706B007E for ; Tue, 30 Nov 2021 16:41:50 -0500 (EST) Received: from smtpin07.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id E2B1D8249980 for ; Tue, 30 Nov 2021 21:41:39 +0000 (UTC) X-FDA: 78866918718.07.CB6164C Received: from out1.migadu.com (out1.migadu.com [91.121.223.63]) by imf25.hostedemail.com (Postfix) with ESMTP id 47AACB000184 for ; Tue, 30 Nov 2021 21:41:34 +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=1638308497; 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=2VlRNVgjD8s3LiQBttrzG+uL14gJGV2zDjLV32J+vek=; b=O1N5ChXOugWJB6+QRXIZUB5o0s8EIG4DrohccwfveR/ePyG/uOTU2Vr3uQ5CLC5yZ0d+0A eGSsm6vFEgIjBpqKJdRm/maniY9N+gPYUEDQvLIb0sapJp7Yek5uLmAeDiRXfQRcILFV2y bxPZpZ/X4eJsx3ImbI/t3f5FciFB7xs= From: andrey.konovalov@linux.dev To: Marco Elver , Alexander Potapenko , Vincenzo Frascino , Catalin Marinas , Peter Collingbourne Cc: Andrey Konovalov , Dmitry Vyukov , Andrey Ryabinin , kasan-dev@googlegroups.com, Andrew Morton , linux-mm@kvack.org, Will Deacon , linux-arm-kernel@lists.infradead.org, Evgenii Stepanov , linux-kernel@vger.kernel.org, Andrey Konovalov Subject: [PATCH 06/31] mm: clarify __GFP_ZEROTAGS comment Date: Tue, 30 Nov 2021 22:41:28 +0100 Message-Id: <4f6d3dd6f1ab9d7774c96ca0ad6d8cabebf0914b.1638308023.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-Server: rspam06 X-Rspamd-Queue-Id: 47AACB000184 X-Stat-Signature: mqhyf7ekq7uub8szcxwnsi7yrc7krqrg Authentication-Results: imf25.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=O1N5ChXO; spf=pass (imf25.hostedemail.com: domain of andrey.konovalov@linux.dev designates 91.121.223.63 as permitted sender) smtp.mailfrom=andrey.konovalov@linux.dev; dmarc=pass (policy=none) header.from=linux.dev X-HE-Tag: 1638308494-614180 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 --- 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 b976c4177299..dddd7597689f 100644 --- a/include/linux/gfp.h +++ b/include/linux/gfp.h @@ -232,8 +232,8 @@ 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