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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 99B33CF8540 for ; Thu, 20 Nov 2025 06:11:57 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 00E446B0005; Thu, 20 Nov 2025 01:11:57 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id F00826B002A; Thu, 20 Nov 2025 01:11:56 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E17366B002B; Thu, 20 Nov 2025 01:11:56 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id CD40F6B0005 for ; Thu, 20 Nov 2025 01:11:56 -0500 (EST) Received: from smtpin22.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 74FB1C070A for ; Thu, 20 Nov 2025 06:11:56 +0000 (UTC) X-FDA: 84129964632.22.96A54FF Received: from out-183.mta0.migadu.com (out-183.mta0.migadu.com [91.218.175.183]) by imf04.hostedemail.com (Postfix) with ESMTP id 8D3AA4000A for ; Thu, 20 Nov 2025 06:11:54 +0000 (UTC) Authentication-Results: imf04.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=ixJRlqmY; spf=pass (imf04.hostedemail.com: domain of lance.yang@linux.dev designates 91.218.175.183 as permitted sender) smtp.mailfrom=lance.yang@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1763619114; 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:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=Eh3iY/0Dx1yebP0GWfJ20Z3mrY3JQYu3VbYsy5OeNlA=; b=VRkzHbT0DsiUBS2UVDJUs4ZF2W1XpqOG78Wr1lDgZllMFWghdhhlw6jonuWfrqY4zmpGgn aIawxnA5SzV0tMtR38kuNXzkjKixgbmWek4rd6BHmz88DWNqBpENVplC8TWU9QdtqWcxT8 w/d2TeMKqzI+EQiZTqN2ImUTJNYU0VE= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1763619114; a=rsa-sha256; cv=none; b=ZfK5VoHP1nmIPgR21C/bod0/JdxBHYo2daJxekaC7oEwoPNHV07j4QfK85E1jy9rG+sXTI ztC1S54rSX6sFHFQenKI7kDjS798CheEy3DheilvCc2GDKsRnTY1q/ElSWLbkpf4NCeENn aRVFp1qwMiq9bflhhkIgNHQ4+1CBetc= ARC-Authentication-Results: i=1; imf04.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=ixJRlqmY; spf=pass (imf04.hostedemail.com: domain of lance.yang@linux.dev designates 91.218.175.183 as permitted sender) smtp.mailfrom=lance.yang@linux.dev; dmarc=pass (policy=none) header.from=linux.dev Message-ID: <91396181-1813-4ea1-a081-06f97e703be3@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1763619111; h=from:from: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:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Eh3iY/0Dx1yebP0GWfJ20Z3mrY3JQYu3VbYsy5OeNlA=; b=ixJRlqmYUW1hPKe2xcV+KHpM+JSSHkyJfk9zszG6yWhPbjZfGTICW8vMWpGZI9vjz+FI/R ALPqYtWd8htC60MUwW3NmoaHhXYj36vA+J8x3dEhu8jATndgvAxM14mSzfekV2fsaocrvx Gu2ajojAgC+vbqu80mUjxZIOhc0a5O8= Date: Thu, 20 Nov 2025 14:11:39 +0800 MIME-Version: 1.0 Subject: Re: [PATCH v4 2/9] mm: add atomic VMA flags and set VM_MAYBE_GUARD as such To: Lorenzo Stoakes Cc: Jonathan Corbet , David Hildenbrand , "Liam R . Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , Jann Horn , Pedro Falcato , Zi Yan , Baolin Wang , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, Andrei Vagin , Andrew Morton References: <97e57abed09f2663077ed7a36fb8206e243171a9.1763460113.git.lorenzo.stoakes@oracle.com> Content-Language: en-US X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Lance Yang In-Reply-To: <97e57abed09f2663077ed7a36fb8206e243171a9.1763460113.git.lorenzo.stoakes@oracle.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 8D3AA4000A X-Stat-Signature: ysa1rpa9mrgznqubxre9tjc33hgim1py X-Rspam-User: X-HE-Tag: 1763619114-915740 X-HE-Meta: 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 QBfZaFWA zpdoPf8wnQC3ZbhWEk041oO1V6wIyUd7i+2RIqUc1xpTjcOZmPl3rPaGlg8eX5XF9BdmOyqf0pVNbLsqRweSnvN0gxAsNJbceXK1r4hOqK1BXYMwUw75QwyqsTTHRWlzN1NImKi4oO7cViQyeKncNKa79cMjAFEE9Hd4t2ORuC7zQtfpkT5fCEsSgSPY1jKeJOV4Q38xZeieZ+N1lYC4L9K+3n1hZwZa/3mMl2wffloYiobtUZQ9HhArWE4xEpR6IANBTEF2B1cP5MwuR4xgke43SjO61G9p2FyXuOm03FM+uOX/6RNl2dzzG5bKLaHBvWAHW 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: List-Subscribe: List-Unsubscribe: On 2025/11/18 18:17, Lorenzo Stoakes wrote: > This patch adds the ability to atomically set VMA flags with only the mmap > read/VMA read lock held. > > As this could be hugely problematic for VMA flags in general given that > all other accesses are non-atomic and serialised by the mmap/VMA locks, we > implement this with a strict allow-list - that is, only designated flags > are allowed to do this. > > We make VM_MAYBE_GUARD one of these flags. > > Signed-off-by: Lorenzo Stoakes > Reviewed-by: Pedro Falcato > Reviewed-by: Vlastimil Babka > --- LGTM! Feel free to add: Reviewed-by: Lance Yang