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 051F4C433F5 for ; Tue, 14 Dec 2021 19:56:28 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 1EC2A6B0071; Tue, 14 Dec 2021 14:56:18 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 14DA66B0073; Tue, 14 Dec 2021 14:56:18 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id EE3446B0074; Tue, 14 Dec 2021 14:56:17 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0004.hostedemail.com [216.40.44.4]) by kanga.kvack.org (Postfix) with ESMTP id D7E8D6B0071 for ; Tue, 14 Dec 2021 14:56:17 -0500 (EST) Received: from smtpin15.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 9ABFD180CB06E for ; Tue, 14 Dec 2021 19:56:07 +0000 (UTC) X-FDA: 78917455974.15.72E68EB Received: from mail-wr1-f51.google.com (mail-wr1-f51.google.com [209.85.221.51]) by imf13.hostedemail.com (Postfix) with ESMTP id 9C93D2000F for ; Tue, 14 Dec 2021 19:56:03 +0000 (UTC) Received: by mail-wr1-f51.google.com with SMTP id a18so34325695wrn.6 for ; Tue, 14 Dec 2021 11:56:07 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=wS77TqqTPnBTpmksYhdz3eSRMai6KqIllrvJewhLyWE=; b=FK8LQs2jZHxN78dHSNnrvFkYm0T4xDtpiUBawSlgn169PaOnn1oebfe5XyxSi7S5B+ lC3qo7f10AVt794TSxtbhb5OLUExwX4AU+nvfA7Y9X94rElmxbAbVmBwFRB+9r2o+B45 1US5ap8R6GFmAEzPUbnFhap5TXHxhnVc2HxVgQuU9lx43GCEzPcuOXuLrx+s+vTDJejn gSUGN+x/lZ5E88ho2XOdDyzNLg1p9SECnEcaQcuckkHyrEaYKjVIaJGRjXCKcmxm3Gnw B6ZixaxPO9JnYFEQpJ3f35l6SUnVjBzRifD010ufEj066nu67da3ZzAgMd6fHwydEyHa ytOw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=wS77TqqTPnBTpmksYhdz3eSRMai6KqIllrvJewhLyWE=; b=CZMeUZd7WnlhO5oWEnbXE9qRfWK6JWmQk6cavcgmEzD7hLTQQ7CFAZSdQKBOKgStPd Kum06EjIWmb5NiQmWe+4m2Mi2LK+W1jgcFNyxiQs5f1Ruuwr1OT2vzkyg2mVnmETj/aI ZNmvKkph0t16Fhhre65oaPT0mfM+uStn0qZTVTwijP0wqNAmR5GHxvkZZP5mbTQeE0XG RXyOovDAYElI5NN+JbJvqi9Y9WAMnI2m3A0fsuAhHlh49i6pJskq9YVozu8Tq/pfF6In uHnhrPzdfNWxGETjTJR+OQwPvyO2Fv/autCi3C2tnyJnN9nkpS6yxBKKHEJO25Na6sMk +5wg== X-Gm-Message-State: AOAM531ZlDvGGynreMgdqiW2oNzCWn+QLvDYPGudoUZ7p7St84bf1git AhBQ6ZoTW0LRDma9h5srzArvHA== X-Google-Smtp-Source: ABdhPJzjOMfuJ4ickmlh1ep17YBYjPJwE4BK843Qs8UJvreheviMvgUN/HF6dUwCslE1l0bhNDQGRA== X-Received: by 2002:adf:c10e:: with SMTP id r14mr1212852wre.558.1639511765820; Tue, 14 Dec 2021 11:56:05 -0800 (PST) Received: from elver.google.com ([2a00:79e0:15:13:f9c2:fca2:6c2e:7e9f]) by smtp.gmail.com with ESMTPSA id bg34sm3343256wmb.47.2021.12.14.11.56.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 14 Dec 2021 11:56:05 -0800 (PST) Date: Tue, 14 Dec 2021 20:55:58 +0100 From: Marco Elver To: andrey.konovalov@linux.dev Cc: Alexander Potapenko , Andrew Morton , 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: Re: [PATCH mm v3 29/38] kasan, vmalloc: add vmalloc tagging for HW_TAGS Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/2.0.5 (2021-01-21) Authentication-Results: imf13.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=FK8LQs2j; spf=pass (imf13.hostedemail.com: domain of elver@google.com designates 209.85.221.51 as permitted sender) smtp.mailfrom=elver@google.com; dmarc=pass (policy=reject) header.from=google.com X-Rspamd-Queue-Id: 9C93D2000F X-Stat-Signature: 9puhxnzi1zbpqrgi1uhxktoioty8m5h7 X-Rspamd-Server: rspam04 X-HE-Tag: 1639511763-504332 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 Mon, Dec 13, 2021 at 10:54PM +0100, andrey.konovalov@linux.dev wrote: [...] > > + /* > + * Skip page_alloc poisoning and zeroing for pages backing VM_ALLOC > + * mappings. Only effective in HW_TAGS mode. > + */ > + gfp &= __GFP_SKIP_KASAN_UNPOISON & __GFP_SKIP_ZERO; This will turn gfp == 0 always. Should it have been gfp |= __GFP_SKIP_KASAN_UNPOISON | __GFP_SKIP_ZERO Also, not sure it matters, but on non-KASAN builds, this will now always generate an extra instruction. You could conditionally define GFP_SKIP* only in the KASAN modes that need them, otherwise they become 0, so the compiler optimizes this out. (Although I think it does does complicate GFP_SHIFT a little?)