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 A89B1C71148 for ; Fri, 13 Jun 2025 14:23:25 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 4BF956B0098; Fri, 13 Jun 2025 10:23:25 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 496E06B0099; Fri, 13 Jun 2025 10:23:25 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3AC6E6B009A; Fri, 13 Jun 2025 10:23:25 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 18F476B0098 for ; Fri, 13 Jun 2025 10:23:25 -0400 (EDT) Received: from smtpin04.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id CDAD9101063 for ; Fri, 13 Jun 2025 14:23:24 +0000 (UTC) X-FDA: 83550595128.04.AC288CF Received: from mail-wm1-f54.google.com (mail-wm1-f54.google.com [209.85.128.54]) by imf11.hostedemail.com (Postfix) with ESMTP id C63BD40002 for ; Fri, 13 Jun 2025 14:23:22 +0000 (UTC) Authentication-Results: imf11.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=gxwI9VGh; spf=pass (imf11.hostedemail.com: domain of usamaarif642@gmail.com designates 209.85.128.54 as permitted sender) smtp.mailfrom=usamaarif642@gmail.com; dmarc=pass (policy=none) header.from=gmail.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1749824602; 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=84RcY3DfzLp25TcLhTlTuyGAU6oDl+5WCZicaPJ+WkQ=; b=RiksNb25DLfp8WvFV849m0z9j84vsSGwj1RtjELbh5Mmqxs/p0DlwC+OPMta4Qei9J/XjJ 8YxDGT9Xs21upQE4D4FOMWEhud10VSMxu4Ry8VtzScuXMu4npWY3ZC5lHajQFIvJZaq9C6 Nyzv4HhQbuanBPEFB+mm+Te/3eqIfQU= ARC-Authentication-Results: i=1; imf11.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=gxwI9VGh; spf=pass (imf11.hostedemail.com: domain of usamaarif642@gmail.com designates 209.85.128.54 as permitted sender) smtp.mailfrom=usamaarif642@gmail.com; dmarc=pass (policy=none) header.from=gmail.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1749824602; a=rsa-sha256; cv=none; b=sdnWpbllzZ6Q/icaCG4js+WSaJKKpsr2UENodXzSzTVx5Cxlw7zHLfthn0stPKFmWKKqmr hi+HLvFYOzuNrMc6SrCtZ0+0VEbVSuMMGKe2NJ234qx6mdtW+MjWNqX/4ol1Eezo5EmOaD yGJwOwsX3WDsjevrqb8AKbj5SIIkJwc= Received: by mail-wm1-f54.google.com with SMTP id 5b1f17b1804b1-43ea40a6e98so25755905e9.1 for ; Fri, 13 Jun 2025 07:23:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1749824601; x=1750429401; darn=kvack.org; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=84RcY3DfzLp25TcLhTlTuyGAU6oDl+5WCZicaPJ+WkQ=; b=gxwI9VGhkCLy/q1cLVdoRjCo32ZV8ih+dYwiAz+j82RRAcW/aR5xHk7FkGFmHfIHwy uD31UT3uIWEinRqdYPZ27nhxkqOmI+W9f8K3Ov8R2ZRRBLrsk/7XtM7iFvDU3Znukw8O l9k2okZt1aEzVhi9FRcVVNt+wKuuax22wJciOrT+JGVTjAg6MYiD53S4t+oOVZhgW4tJ /e6f4/64XMtM38JKE1CVYByq7l8aPxiurE0xS3RNd/SRE4PpGxmBdYNWt3ULRsSoinoB 2Gm0NWanrYA5f6GBxXLrhvfDjbbXI+kEbTMooRQrcymW5za7VMExpjAtWwvfB9OqRkVJ J1Hw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1749824601; x=1750429401; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=84RcY3DfzLp25TcLhTlTuyGAU6oDl+5WCZicaPJ+WkQ=; b=PconswY98wp6QaG65aJAhHCMJnMKr6mTZ1AhNfmVGV4NaGNjs3QSejYqXG4J+S1BSe J1lNsVW3YWTn6MTWj4FRFf+Z4nwPJ5zqUWvRC/b6/TsLYgAWDfUAgwOSBv2IU0eB8SiR kRLyqw175k/Ecl6qjSpSov7qE8aMNWGjazybqaDihhs0XBjQcl0bqP5Wyd+ov3l25j7Q 7DaTEE3qR9Uu7gPTcimj7U4j8HxAUSCSAIp2+V+ZLs24hGdY6IeLTAGxA4hBc2bTWld/ 0Bx9gCfRb2XVAsK8iqw2usujCFRlstXYzl2N3tREfu3wJnfabzvNk6uruLElqnyyZQ2M 2d6w== X-Forwarded-Encrypted: i=1; AJvYcCXNR+vqw70Zz/uwl3mpiBfXx6FyFzSxWSp+nf7HXsqvzEZYhwER3ZE9d7viCFfky3kCFJFhG4Pfzg==@kvack.org X-Gm-Message-State: AOJu0YyLKGNvslLS20Zn4doEaOS1KuaMX4PWoU5y9A/iaUgSQSkmyKi+ i9oJvb5R5zCBMN0SLWeuoAAJ0oREHtY8UY6GlB6M2lihWLOmpIn9+oyG X-Gm-Gg: ASbGncvgS9b1RzeCBNmJv58pBakYLYRqCLr5by88oI1hBzqReIQMUl7Q2gWQeA8v5qY TC7ocsfiGSxqktHvo737rotxj7MU49nOfNtTh0lLWGy9nn3/z++vfzKqE8+aO76x/VbP/a23TYM ISlu0xhAhf/TaSAT7hH89u1ZTl6g2kcNcjTCstva5QKXatZXruNmEmw5ylslpq7FEUWRSjogBd0 cnJu1t2IhrKpM3il2pIt7yg5oAhV+cQ9/iri1RzFKxW0LdG/jnca6oz9g3/LRdmdO7YLZyMGdzs s2YHJ4pbhdvf0E0AZ8ySfQPYVbpJS6uIN2zXbK1MgtCIBMOmcRtA/q56aFoqexN2kWwWxS+DJHT mn4x1cNcWK7GTgHBemWEdtjMy19iKGJY/tlhYT4Ke83ReSI5T/zXI/GYeTw== X-Google-Smtp-Source: AGHT+IFgxrebvzgWr4HuigiiNgf4KeU1NI+nQXYGx46ksABIGgE/Qu352CXSVtYKZn6vksiHyzfGRA== X-Received: by 2002:a05:600c:890c:b0:43d:4686:5cfb with SMTP id 5b1f17b1804b1-45335675dd1mr22066855e9.27.1749824600913; Fri, 13 Jun 2025 07:23:20 -0700 (PDT) Received: from ?IPV6:2a02:6b6f:e750:f900:146f:2c4f:d96e:4241? ([2a02:6b6f:e750:f900:146f:2c4f:d96e:4241]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-3a568b4cc7bsm2486501f8f.86.2025.06.13.07.23.20 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 13 Jun 2025 07:23:20 -0700 (PDT) Message-ID: Date: Fri, 13 Jun 2025 15:23:19 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 0/2] fix MADV_COLLAPSE issue if THP settings are disabled To: Baolin Wang , akpm@linux-foundation.org, hughd@google.com, david@redhat.com Cc: lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, npache@redhat.com, ryan.roberts@arm.com, dev.jain@arm.com, ziy@nvidia.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: Content-Language: en-US From: Usama Arif In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: C63BD40002 X-Stat-Signature: nx3iw89hzmcasha3bcjszr3n6ko5oru7 X-Rspam-User: X-HE-Tag: 1749824602-375701 X-HE-Meta: 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 Sg05ATFm 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 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 05/06/2025 09:00, Baolin Wang wrote: > As we discussed in the previous thread [1], the MADV_COLLAPSE will ignore > the system-wide anon/shmem THP sysfs settings, which means that even though > we have disabled the anon/shmem THP configuration, MADV_COLLAPSE will still > attempt to collapse into a anon/shmem THP. This violates the rule we have > agreed upon: never means never. This patch set will address this issue. Hi Baolin, I know never means never, but I also thought that the per-size toggles had priority over the system ones. This was discussed in [1] as well. My understanding with these patches is that if we have: [root@vm4 vmuser]# cat /sys/kernel/mm/transparent_hugepage/enabled always madvise [never] [root@vm4 vmuser]# cat /sys/kernel/mm/transparent_hugepage/hugepages-2048kB/enabled always inherit [madvise] never Than without these patches we get a hugepage when we do MADV_HUGEPAGE, but with these we won't get a hugepage anymore eventhough hugepages-2048kB/enabled is set to madvise? I know this isn't ABI, but this would break existing expectations. (For e.g. we have certain 64K page size arm machines with global enabled = never and 2M = madvise, and we want 2M hugepages to fault at madvise). If the whole thing was being implemented from scratch, we should have definitely done it this way, but this can give a people a nasty surprise when they upgrade the kernel and suddenly stop getting hugepages. [1] https://lore.kernel.org/all/97702ff0-fc50-4779-bfa8-83dc42352db1@redhat.com/ Thanks, Usama