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 567B2CD4851 for ; Thu, 14 May 2026 11:07:22 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 8A30F6B0088; Thu, 14 May 2026 07:07:21 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 853E96B008A; Thu, 14 May 2026 07:07:21 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 769B36B008C; Thu, 14 May 2026 07:07:21 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 66D616B0088 for ; Thu, 14 May 2026 07:07:21 -0400 (EDT) Received: from smtpin24.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay01.hostedemail.com (Postfix) with ESMTP id F2D2B1C0727 for ; Thu, 14 May 2026 11:07:20 +0000 (UTC) X-FDA: 84765749040.24.D81E6C7 Received: from stravinsky.debian.org (stravinsky.debian.org [82.195.75.108]) by imf22.hostedemail.com (Postfix) with ESMTP id 3A416C0007 for ; Thu, 14 May 2026 11:07:18 +0000 (UTC) Authentication-Results: imf22.hostedemail.com; dkim=pass header.d=debian.org header.s=smtpauto.stravinsky header.b=FSkv2BFN; spf=pass (imf22.hostedemail.com: domain of leitao@debian.org designates 82.195.75.108 as permitted sender) smtp.mailfrom=leitao@debian.org; dmarc=pass (policy=none) header.from=debian.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1778756839; 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=8ajRUalzhgnnfvlPn0WFR2fLEgViH6plKkchspfix3c=; b=0cqAErM0tt/n++pJQz+yaZyxhNEJEHnT1+80bniheHsSXuCDRmkTgER/4Au+huuKdOCxpF 9GxLiz2PLjH4nxnGm9relt3sRH5gpnMiaQdlgQSmB+XOAlO8ip7eXk8tRO1tbbbz7aSYVs o8y/74/Ud0KpuPa7zwSusQfwWAyvbto= ARC-Authentication-Results: i=1; imf22.hostedemail.com; dkim=pass header.d=debian.org header.s=smtpauto.stravinsky header.b=FSkv2BFN; spf=pass (imf22.hostedemail.com: domain of leitao@debian.org designates 82.195.75.108 as permitted sender) smtp.mailfrom=leitao@debian.org; dmarc=pass (policy=none) header.from=debian.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1778756839; a=rsa-sha256; cv=none; b=8riKYtvBI+Z49uosDuGHiC9ajbCcSV30Y5oBej8I3MVt0MukpT420DoOe2Tbmyq2tg9UYK FVgvuTBFT1HgWuJ/Uj/I/5zLqi6QN34lc2hTpgDrK3lrAoppPDmWxoXxkyrjzz7QzTCkCZ 3YpsbFKOYxMtpZP6fq48qOUA+84bGJ8= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=debian.org; s=smtpauto.stravinsky; h=X-Debian-User:In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=8ajRUalzhgnnfvlPn0WFR2fLEgViH6plKkchspfix3c=; b=FSkv2BFN8Uucm7POm/m+FRQU/f OKnEJNeRs5TovgCDj71pFKXBJ1ywjwTYpsPkhqP9CZJSYJ2pJwTrRoWL15Kaz7/MMYxMntaic2dBR YWzDWy8dFIHIw5lFZC/dpG4I+/ayRH3T7wofabgAeBm2v8IZqoGuF3ep2U5WdJxuGiIevSKY5ovUV PD3MK0HHzJHnjLAcT2nyMQDmdsvV/0brczMU5K6/j0LxqEhDkA6JWF034qbFbC82lluwRPT0hgXgz QVNwSPf7c6MuOxJy4ycOlhxtvmO22G61aJu46aH+Dhl//jaXkvhovISFZBaHZaZKCfruOsjKVAYPn +t0uCj8A==; Received: from authenticated user by stravinsky.debian.org with esmtpsa (TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.96) (envelope-from ) id 1wNTu6-003tUh-22; Thu, 14 May 2026 11:06:59 +0000 Date: Thu, 14 May 2026 04:06:51 -0700 From: Breno Leitao To: "David Hildenbrand (Arm)" Cc: Miaohe Lin , Andrew Morton , Lorenzo Stoakes , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Shuah Khan , Naoya Horiguchi , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , Jonathan Corbet , Shuah Khan , "Liam R. Howlett" , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-trace-kernel@vger.kernel.org, kernel-team@meta.com, Lance Yang Subject: Re: [PATCH v7 4/6] mm/memory-failure: short-circuit PG_reserved before get_hwpoison_page() Message-ID: References: <20260513-ecc_panic-v7-0-be2e578e61da@debian.org> <20260513-ecc_panic-v7-4-be2e578e61da@debian.org> <511dc52e-f2af-43c8-a9cf-19321b091dbe@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <511dc52e-f2af-43c8-a9cf-19321b091dbe@kernel.org> X-Debian-User: leitao X-Rspam-User: X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 3A416C0007 X-Stat-Signature: jx61sc56k4heewsoukaoz5zh8cqy8exh X-HE-Tag: 1778756838-710821 X-HE-Meta: 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 DvP1gPDq Qu26C1Ed42CGuzxQNUJRWyT6ndarXRLwxnzfoQ2npOp4Ho6HjhAX60kHJtAf0rSi4zURjjU7qLfa9i4T+90vwfLcIN0+yp9/baHDj5gVxaPESQrjvJwmyZ0RS1+jdtu04qD+S0agU3McT2em8OukHA/7dXFg0eraO70pA9Uss+t9a/FK4D1yR0S3IY3XWf3QWStn95r8WVMpgR6EySOwKHjiC/hUPvOYFrYQtJ2NyHhRuEQaoML/thFwwr6BdptW16VZ7LVnpyOmbNbTAsipyoTtp/LzVH9GzwS5Yq0vAriB/gL8D/0Thjy2mPQl4wT8NBXm2fA+zYRsCEE5p0/KEnTG2RrlsNtfHuNVg Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, May 13, 2026 at 09:49:28PM +0200, David Hildenbrand (Arm) wrote: > On 5/13/26 17:39, Breno Leitao wrote: > > The previous patch already classifies PG_reserved pages as > > MF_MSG_KERNEL through the long path: get_hwpoison_page() calls > > __get_hwpoison_page() which fails HWPoisonHandlable(), get_any_page() > > exhausts its shake_page() retry budget, and the resulting > > -ENOTRECOVERABLE is mapped to MF_MSG_KERNEL by the switch. The > > outcome is correct but the work in between is wasted: shake_page() > > cannot turn a reserved page into a handlable one. > > If really required, can we just move the check right there, into get_any_page() etc? Sure, we might move it to get_any_page(). I took this current approach based on the following facts: 1) Lance suggested it, and it sounded a good idea. https://lore.kernel.org/all/20260512124837.38883-1-lance.yang@linux.dev/ 2) There is a _similar_ check close to this one in memory_failure(), just before this one: if (TestSetPageHWPoison(p)) { .... action_result() goto unlock_mutex; } and now if (PageReserved(p)) { ... action_result() goto unlock_mutes; } 3) I wanted to give get it as real layering point, not handwaving. That said, I will short-circuit reserved pages inside get_any_page(), in an updated version. Again, thanks for the review and direction! --breno