From patchwork Mon Dec 6 21:43:44 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: 12694992 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 92699C433EF for ; Mon, 6 Dec 2021 21:47:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=gJUEXnslc4iN4vNTI8ALP21g/q1hDRO8kSWpysOxW8g=; b=xqNR3sHE6VXQZy 9aDXEElaKRhOfHsBak/EcXciS7SjRvWsV8XEGsy2Mar40WglpUsLfWTqn0zCKYW+/cnBxp/xQl+lV njXXIWorZTLH1expwSCr77G32GVdHgcZpNmEUrcwzROPdgpQCaOe+tRUzy/jSemqIT9bO9p+cJ9pK Hb2FFiE1BG20ao2Na6Fvq9uc+PrXYJ5VVCGz/r2FU79ueuwb63wDWE5qDBdae6cB0sjRtRicI3+gw lhZdPN1xHxwPJy2WaRuu1wwH9KQLgUFbCqsK55dW8F9TePMT85eUTdjb5+/gA61lJMkF49L3rUABX N2vxX+vs6zkxYVLk1BXw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1muLoV-005zO0-1G; Mon, 06 Dec 2021 21:46:24 +0000 Received: from out2.migadu.com ([188.165.223.204]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1muLmk-005ykv-O3 for linux-arm-kernel@lists.infradead.org; Mon, 06 Dec 2021 21:44:36 +0000 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=1638827073; 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=TD3DS7kX7rNKsdKtOiQfPuRZoLtKBoyf7SJg3jpF4rxc0wxHBoJHLYeR2c6s/YbyY6uLog 5APt5A1zwI3YC58xavMrB9D7v31ne2TlVFuxLLSpZf+HaEztsc2oWCXxMaaVxulkDWL0aM J4XRIiAZyUo1nVCnDbXOAGcx88Hqa+4= 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 , Mark Rutland , linux-arm-kernel@lists.infradead.org, Evgenii Stepanov , linux-kernel@vger.kernel.org, Andrey Konovalov Subject: [PATCH v2 07/34] mm: clarify __GFP_ZEROTAGS comment Date: Mon, 6 Dec 2021 22:43:44 +0100 Message-Id: In-Reply-To: References: MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT X-Migadu-Auth-User: linux.dev X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211206_134434_971228_9674DDC0 X-CRM114-Status: GOOD ( 12.73 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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