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 A3CBECAC5BB for ; Wed, 1 Oct 2025 09:38:39 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id AA8E78E0007; Wed, 1 Oct 2025 05:38:38 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id A7F828E0006; Wed, 1 Oct 2025 05:38:38 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 99FAE8E0007; Wed, 1 Oct 2025 05:38:38 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 82DCE8E0006 for ; Wed, 1 Oct 2025 05:38:38 -0400 (EDT) Received: from smtpin24.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 301C0BC508 for ; Wed, 1 Oct 2025 09:38:38 +0000 (UTC) X-FDA: 83949045516.24.8E0DC63 Received: from out-172.mta1.migadu.com (out-172.mta1.migadu.com [95.215.58.172]) by imf15.hostedemail.com (Postfix) with ESMTP id 45263A0005 for ; Wed, 1 Oct 2025 09:38:36 +0000 (UTC) Authentication-Results: imf15.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=gJ3r1JI5; spf=pass (imf15.hostedemail.com: domain of lance.yang@linux.dev designates 95.215.58.172 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=1759311516; 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=GV4zvLAZCIS+DJquNo2kGvLSwP9qlPaKfOY4TEmQGuw=; b=h9ROT3/rPXr9qypQdyzJbDQh9yJDNEmrpR9PpWz34RHL7KR7p673PfylquSiPo3elfzKMJ z3MF0dRt7g/Y/2z+RJ4cYjsOxIDDQ2oBNaF/dkkckza5Zkc9NhRirB3AzmxF3EAj8bHYCQ eZRycxBjKZyGEKLIvn8c6ywUaNNWp/Y= ARC-Authentication-Results: i=1; imf15.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=gJ3r1JI5; spf=pass (imf15.hostedemail.com: domain of lance.yang@linux.dev designates 95.215.58.172 as permitted sender) smtp.mailfrom=lance.yang@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1759311516; a=rsa-sha256; cv=none; b=BhBEh8a8Pwh/wGNZbnCJxbYd8vXS8+ayLmxksC8Ynk76KuKie9gMhcGnTWmMfJUG1JFmSz FySUyrFnON0h/8uGxDK/fsUt2q1k7vak7OgwRVV1e9NvDMdmFJsOGSWtHZFfUEMkvql9NE zs/OXSE3FfVMFfm3Dj8PmuCb1MFjrl0= Message-ID: <4640ec4f-57ee-40f1-92c1-6bc703de7933@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1759311513; 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=GV4zvLAZCIS+DJquNo2kGvLSwP9qlPaKfOY4TEmQGuw=; b=gJ3r1JI5yO396r9SYNygihameJKZ6f9cXVO1ivaQvB4rLWWT2b9k+EWJydC9FYOwu9QUe1 JSjK/3oFbWbQ8+theezba8BRMS83uSkYEYJOj4UKekV3eOEeFi7IxVUKfnUOYWfT6VVg2g QsTD+DmU8dHl8a0y0ATkGDi3LPbe7Ko= Date: Wed, 1 Oct 2025 17:38:22 +0800 MIME-Version: 1.0 Subject: Re: [PATCH mm-new v2 1/1] mm/khugepaged: abort collapse scan on non-swap entries Content-Language: en-US To: David Hildenbrand Cc: 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, kirill@shutemov.name, 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, akpm@linux-foundation.org References: <20251001032251.85888-1-lance.yang@linux.dev> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Lance Yang In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 45263A0005 X-Stat-Signature: 7g7ke6jo9ojif3ecu4bq5n8mxjab4xee X-HE-Tag: 1759311516-947011 X-HE-Meta: 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 dzjd51h3 WZ3DJvqwr/IbKRd3eF20lwo85HZ8CE9+gbV7cR4bul9qzEmvkX29sa3192EALUENYPXluZrADcLfmEmy3MbxQwHG+12/n3nvrGnZ1KQToGx52yiy8xJzrri3tpf6Unzf5dKmgpXVe+lHWK6d/SVUxjuoXhJl/ddk5m+gfYHNChhJ+FDEZPNkPi4xhOUI8JG1ZGWO+qM+LTa6czAoJvdhIRQ6lDU0oXoyEWfVicc3xXTDx8qWW6WuWxjoImRy1tbeXNJImylyZRAnniWCvgD2D9ENO96VaF/QIKUeFvtKvWFUwUbXg0okhfO/GcvMYyWpewkDxyu0OuMN2O3zsvkv5tNIpbrkgCmxpATkCqUbLjULNtApAVIX+T5ERQg== 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 2025/10/1 16:31, David Hildenbrand wrote: > On 01.10.25 05:22, Lance Yang wrote: >> From: Lance Yang >> >> Currently, special non-swap entries (like migration, hwpoison, or PTE >> markers) are not caught early in hpage_collapse_scan_pmd(), leading to >> failures deep 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 any one is found, the scan is aborted immediately with the >> SCAN_PTE_NON_PRESENT result, as Lorenzo suggested[2], avoiding wasted >> work. >> >> [1] https://lore.kernel.org/linux-mm/7840f68e-7580-42cb- >> a7c8-1ba64fd6df69@redhat.com >> [2] https://lore.kernel.org/linux-mm/7df49fe7-c6b7-426a-8680- >> dcd55219c8bd@lucifer.local >> >> Suggested-by: David Hildenbrand >> Suggested-by: Lorenzo Stoakes >> Signed-off-by: Lance Yang >> --- > > Could have mentioned you adjust the flow of code to resemble what we > have in __collapse_huge_page_isolate(). Thanks for pointing that out! Let's do that separately. I'm working on a follow-up patch that will unify the scanning with the almost-duplicated code as you suggested ;) > > Acked-by: David Hildenbrand Cheers!