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 6B68FCAC5B5 for ; Wed, 24 Sep 2025 10:17:07 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id C95078E0002; Wed, 24 Sep 2025 06:17:06 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C6C458E0001; Wed, 24 Sep 2025 06:17:06 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id BA9198E0002; Wed, 24 Sep 2025 06:17:06 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id A95E18E0001 for ; Wed, 24 Sep 2025 06:17:06 -0400 (EDT) Received: from smtpin07.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 44B035B01F for ; Wed, 24 Sep 2025 10:17:06 +0000 (UTC) X-FDA: 83923740852.07.A057479 Received: from fout-a5-smtp.messagingengine.com (fout-a5-smtp.messagingengine.com [103.168.172.148]) by imf17.hostedemail.com (Postfix) with ESMTP id 4BE2D40006 for ; Wed, 24 Sep 2025 10:17:04 +0000 (UTC) Authentication-Results: imf17.hostedemail.com; dkim=pass header.d=shutemov.name header.s=fm3 header.b="n T0Sarp"; dkim=pass header.d=messagingengine.com header.s=fm1 header.b=JldBqo5T; spf=pass (imf17.hostedemail.com: domain of kirill@shutemov.name designates 103.168.172.148 as permitted sender) smtp.mailfrom=kirill@shutemov.name; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1758709024; 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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=JDTtAbQOmZtZk8z1Mcd5kf03E8S/F8hNJ0v+YQG+MwE=; b=6rWhKrZsgfgG8J8Op+w9QxUWOnR7sN/AqxSRe/+/lyVnVFF//83UYMlTZkTB8P2to5YZMY 3yRJHNKF6bBa2VuaWSbWK6KZ8joW4gUr7mCCw1hYIwL9HZZ4kNf9qchsj8kHZ+KtMGeBeh +xkH09US0kXxP8wbBGhK6pkOyFisM5M= ARC-Authentication-Results: i=1; imf17.hostedemail.com; dkim=pass header.d=shutemov.name header.s=fm3 header.b="n T0Sarp"; dkim=pass header.d=messagingengine.com header.s=fm1 header.b=JldBqo5T; spf=pass (imf17.hostedemail.com: domain of kirill@shutemov.name designates 103.168.172.148 as permitted sender) smtp.mailfrom=kirill@shutemov.name; dmarc=none ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1758709024; a=rsa-sha256; cv=none; b=2//BO5fBrtCF4FvM27H0leLFpQkXLRGCmpOK0KsCODgfgN3e/WEzlhqSkZZhLJwLuDJNkX VeVVdTd8av+V2KuNJirkqpOsA4hzTtCZB3DjDFTSKa9ybq8mXyadVxRB1VJWGuoLj8mWyF i0vBpI1smJwqxZVWCp/yWcpbic5G0PU= Received: from phl-compute-02.internal (phl-compute-02.internal [10.202.2.42]) by mailfout.phl.internal (Postfix) with ESMTP id B033EEC0183; Wed, 24 Sep 2025 06:17:03 -0400 (EDT) Received: from phl-mailfrontend-02 ([10.202.2.163]) by phl-compute-02.internal (MEProxy); Wed, 24 Sep 2025 06:17:03 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=shutemov.name; h=cc:cc:content-type:content-type:date:date:from:from :in-reply-to:in-reply-to:message-id:mime-version:references :reply-to:subject:subject:to:to; s=fm3; t=1758709023; x= 1758795423; bh=JDTtAbQOmZtZk8z1Mcd5kf03E8S/F8hNJ0v+YQG+MwE=; b=n T0Sarpa/KG1+uAkBBQqbXY4rEH/R2AorxuNHbF0W558Z4sbBbe0Z0+rZF8OYQsZK BU+mCgZFhEOq7OntNt+IksY1Vx9bkdnsFIavtxbpntIGjMNPBMYCZUSnu8/ep4aP 7DQ9ogy7n/M3zv3OcTbQLrMxjVteBUcqU+eXf/NsGWj+ARXx0Mu+ZDXTn6KDBnWT AzyMEwpVKQWae2P6ZSnjxG6ydKd0vHoSxcwW3qJ9GDGTTYTF1aAv0vEcPPorpfd6 wKV+ezp0sWgtqlot/6kGFxkoozo5mPCGDJeU6HKobCO2Aegu4x52bpWiXW9vc3f0 qPL9SNjH/oThyUZaO1Jyw== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:cc:content-type:content-type:date:date :feedback-id:feedback-id:from:from:in-reply-to:in-reply-to :message-id:mime-version:references:reply-to:subject:subject:to :to:x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s=fm1; t= 1758709023; x=1758795423; bh=JDTtAbQOmZtZk8z1Mcd5kf03E8S/F8hNJ0v +YQG+MwE=; b=JldBqo5TO55HJf2/UnRQWnRhe5UJYTVIDlVKXKfbfdFTDbdejoL DCSH9xcw8jrDOn82r//G6rIotADGSWUQQkm48dIzfNjfKlFVr5KEHKflvRrNzg9N suvcs53R0h1iGMV6IcWSgoB9YOES7uPePyzOGabU3RFp2Dw14oSCZpRV3/auKtjZ amxi4JHd1KrMxMq3e+k4/WnRBlPbf7SDp4Ky1YQsRGDDZZQHWsDj+XguAtTbJ6dJ kG9RkaE6s+l1j//gRfVIb25dKx3GttQblSiYzwyHW9iD+nFMLej3lRpvZRyTaA+f 0+hIEqFDURGCSkT2R3bGnhl9gt+yanpJ/eQ== X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeeffedrtdeggdeifeefhecutefuodetggdotefrod ftvfcurfhrohhfihhlvgemucfhrghsthforghilhdpuffrtefokffrpgfnqfghnecuuegr ihhlohhuthemuceftddtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmdenucfjug hrpeffhffvvefukfhfgggtuggjsehttdfstddttddvnecuhfhrohhmpefmihhrhihlucfu hhhuthhsvghmrghuuceokhhirhhilhhlsehshhhuthgvmhhovhdrnhgrmhgvqeenucggtf frrghtthgvrhhnpeejheeufeduvdfgjeekiedvjedvgeejgfefieetveffhfdtvddtledu hfeffeffudenucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmhepmhgrihhlfhhroh hmpehkihhrihhllhesshhhuhhtvghmohhvrdhnrghmvgdpnhgspghrtghpthhtohepfeeg pdhmohguvgepshhmthhpohhuthdprhgtphhtthhopegurghvihgusehrvgguhhgrthdrtg homhdprhgtphhtthhopehlrghntggvrdihrghngheslhhinhhugidruggvvhdprhgtphht thhopegrkhhpmheslhhinhhugidqfhhouhhnuggrthhiohhnrdhorhhgpdhrtghpthhtoh eplhhorhgvnhiiohdrshhtohgrkhgvshesohhrrggtlhgvrdgtohhmpdhrtghpthhtohep lhhirghmrdhhohiflhgvthhtsehorhgrtghlvgdrtghomhdprhgtphhtthhopegsrghohh hurgeskhgvrhhnvghlrdhorhhgpdhrtghpthhtohepsggrohhlihhnrdifrghngheslhhi nhhugidrrghlihgsrggsrgdrtghomhdprhgtphhtthhopeguvghvrdhjrghinhesrghrmh drtghomhdprhgtphhtthhopehhuhhghhgusehgohhoghhlvgdrtghomh X-ME-Proxy: Feedback-ID: ie3994620:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Wed, 24 Sep 2025 06:17:02 -0400 (EDT) Date: Wed, 24 Sep 2025 11:17:00 +0100 From: Kiryl Shutsemau To: David Hildenbrand Cc: Lance Yang , akpm@linux-foundation.org, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, baohua@kernel.org, baolin.wang@linux.alibaba.com, dev.jain@arm.com, hughd@google.com, ioworker0@gmail.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, mpenttil@redhat.com, npache@redhat.com, ryan.roberts@arm.com, ziy@nvidia.com, richard.weiyang@gmail.com Subject: Re: [PATCH mm-new 1/1] mm/khugepaged: abort collapse scan on non-swap entries Message-ID: <2i5t62obfweid2zrt33vo3boviw4okha4d3gglw76eqv43ofky@pdv3evw5yjmh> References: <20250924100207.28332-1-lance.yang@linux.dev> <1282de5a-3dce-443d-91d1-111103140973@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1282de5a-3dce-443d-91d1-111103140973@redhat.com> X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 4BE2D40006 X-Stat-Signature: zanhoib9tp5sxk4hm5x5847pia7b8nab X-HE-Tag: 1758709024-734904 X-HE-Meta: U2FsdGVkX19AEnCZtjxQ47s8J4SzeWV7FoSoasyrqLogD+cNK6xT+6xxLUBdzU0nz0CY+cTRg6Fux2SGhc9WoDyvexN6gja1BvLk8ArndBF7rdEvaR/LhcsjByywg8zN41Qm3MgQMwZw1S6X8U/hw1YA0O5VXzgNAVkvrk5eNXg4HnCo34Dwkx6dNQDiJvuVvYJxo9JDNqq5DCIL1wlengNsPi/FLp5XWWHdylz8kXQOJhMOJ0nOM8trOAl/fodbjukiSKb1gtEr/Zxw+qc5/vbJS5RS/eJgrG+cqbKzmHJV6BvfuwIDg0W6RS8q17SsJ6FSUieFxC+4HL/jAUrAobME9+YIDMDI7VSotKuTFPi44YzjEjH6Ijz14j0yBnkOzxquxpLWr/Vu6Kon4hZyAy1dZIo8eTT9cu4Oin+nOcQYE2qkjZNEMdd1xh8Pxuvgdq37LOZzyctk92UGX7Qxwmy3YZIzPiruMEW6iBr/DH0GCAJXf/onm4ar8xM+gOIImEfQG9P3ezHMnRHnHRI1X6yIlsI4+L5sf1jN2nxMgM/XS1RbT25lfk9UArfOgrrIWOvP8OVCQU8jjzS7Lqbqog3+v/LOkoWq/4uIVXRUI/9bzKDKV2nvBtOFcijU4TWCMW62w1zTVKz9hlljfv5HDSrulghewNUSTMHtGo1xlV6P4kvi/px1/M/fOn6DdCcmPjDn0VYWfQv4iOwtgztYVp1BMqkUeUv75rJDXTo/qlo9iyk7xp2v4Se+nfkVEJ0a2G0XAsxnYDT07D8i/EPAVEHOZskIc0Afn9bpAe5ZPK51D+Eokr0arq7SBAmjjaGn3ZAtRo0wk7EmVmMqgvacKX8vt+0P8i8LZ11+JYClkj6ZX39fS2c5HS37+yxtQHthmu+yem955Kc+LpPUka/+nDzkR4OjaVkHbh163QPuzFdkBEXVqBizGCQaVxD6fF1Vg2jv+ajth5nLzO/3D+o Mnf2sVqh AeqNNILyKSbFmRN3V5aORwoA/2ux/t4j9M9MReuCfKgh1epdr1a9IX/f2IPD31wkMRQvQqILG03WlAaF5rWeAc6/Yj9jmH8ft7DyPVcSq/30NfkVyJhTPmX2EUIE7RBw6kbXTi4Ork14o3x+vw5v9lVM2kkA1kAhPiExmgaYmKlDs5vxiI/XxksyZBStY6ejayPsytIedo/3gpfNjvqeOc6LVYHDScOkJ2gRHISSaMg7Ds44QH8W8KsWYc85Qcz0yhumFfye7alfndho7k2YUSjnQROhLTHL7RUC+OsuKgP+Rq/sdTVpSTjGFXOCB8aYHtANH2q8NeJWwAZuGDhNCvJZG0B2vg6Qb2RbW64SlKpTsjksSh0V4vdUvcxSCu61ccFx0PMajODf0qi1ZcVWoDlOUJepbWSywZ4e0I803K3pWr8/Zl2opYAZjoQ== 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 Wed, Sep 24, 2025 at 12:10:47PM +0200, David Hildenbrand wrote: > On 24.09.25 12:02, Lance Yang wrote: > > From: Lance Yang > > > > The existing check in hpage_collapse_scan_pmd() is specific to uffd-wp > > markers. Other special markers (e.g., GUARD, POISONED) would not be caught > > early, leading to failures deeper in the swap-in logic. > > > > hpage_collapse_scan_pmd() > > `- collapse_huge_page() > > `- __collapse_huge_page_swapin() -> fails! > > > > As David suggested[1], this patch skips any such non-swap entries early. > > If a special marker is found, the scan is aborted immediately with the > > SCAN_PTE_NON_PRESENT result, as Lorenzo suggested[2], avoiding wasted > > work. > > Note that I suggested to skip all non-present entries except swap entries, > which includes migration entries, hwpoisoned entries etc. Hm. So swap in is fine, but wait for migration to complete is not? Seems odd. -- Kiryl Shutsemau / Kirill A. Shutemov