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 5C628CCA471 for ; Sat, 4 Oct 2025 03:03:28 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 665B98E0008; Fri, 3 Oct 2025 23:03:27 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 63D148E0002; Fri, 3 Oct 2025 23:03:27 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 552988E0008; Fri, 3 Oct 2025 23:03:27 -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 437088E0002 for ; Fri, 3 Oct 2025 23:03:27 -0400 (EDT) Received: from smtpin16.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 9EF2787F3B for ; Sat, 4 Oct 2025 03:03:26 +0000 (UTC) X-FDA: 83958936012.16.52B2511 Received: from out-189.mta1.migadu.com (out-189.mta1.migadu.com [95.215.58.189]) by imf13.hostedemail.com (Postfix) with ESMTP id A464F20013 for ; Sat, 4 Oct 2025 03:03:24 +0000 (UTC) Authentication-Results: imf13.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b="J5giOyR/"; spf=pass (imf13.hostedemail.com: domain of lance.yang@linux.dev designates 95.215.58.189 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=1759547005; 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=A3w0aPrtz6owLHfo4rKJJGMrd3gYAmvp7fLTky+PAPA=; b=Z/TpQ8l/13wkAsrHTu97d4tpmuv5nFbMl/S+ZnizAsBFFpxULPHqIOYtjaK1DvXdOmE3Bh kf1XNfDLXH7/IOIWu7UalTF6Q0mk7l1RP1Y++sS6aJGGRrAWi09XhcNria5tCpvh1GAmO9 2gHuYUlwQc5DW1gdeXfGwgViCgsdUy8= ARC-Authentication-Results: i=1; imf13.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b="J5giOyR/"; spf=pass (imf13.hostedemail.com: domain of lance.yang@linux.dev designates 95.215.58.189 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=1759547005; a=rsa-sha256; cv=none; b=VhnBrxpXZ0PjXZKEJvmWFbxD0TxvzolUCx6dFgRqjJOZULqYhpFmQdE9pgQmKiX8Vnd1JT 1jSuOgHkqw/pU+v6PNJKC9KYtU/yQmR3Kj6rppm+yUMrivAqO0pRMb/hl/LP6iqCoubmn2 LSjhbYGJqcX1Uw6V4HQJtIXiL2cKCoo= Message-ID: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1759547002; 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=A3w0aPrtz6owLHfo4rKJJGMrd3gYAmvp7fLTky+PAPA=; b=J5giOyR/se7ekCKx5d8TRoepFqoYKyM4sDqCkBMDHeM9cIW0yMp4RAR6VjFS9lcB206Qvi IK8YfpHIpHsq9thLfgThvt/61NZg2PZ0NrV569eO5F40KoDftwQ9QVhMGSWTBZUKpvv9Sj /dNa8V8JMS91Y6gcFxNwtcL5OG+VUSY= Date: Sat, 4 Oct 2025 11:03:11 +0800 MIME-Version: 1.0 Subject: Re: [PATCH mm-new 2/2] mm/khugepaged: merge PTE scanning logic into a new helper Content-Language: en-US To: Dev Jain Cc: ziy@nvidia.com, baolin.wang@linux.alibaba.com, Liam.Howlett@oracle.com, npache@redhat.com, ryan.roberts@arm.com, baohua@kernel.org, ioworker0@gmail.com, david@redhat.com, richard.weiyang@gmail.com, linux-kernel@vger.kernel.org, lorenzo.stoakes@oracle.com, linux-mm@kvack.org, akpm@linux-foundation.org References: <20251002073255.14867-1-lance.yang@linux.dev> <20251002073255.14867-3-lance.yang@linux.dev> <0d55d763-81ff-4b99-bb13-3dbb9af53cdc@arm.com> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Lance Yang In-Reply-To: <0d55d763-81ff-4b99-bb13-3dbb9af53cdc@arm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT X-Stat-Signature: zszhqizt81hyeih77q5am4udouzeed3e X-Rspam-User: X-Rspamd-Queue-Id: A464F20013 X-Rspamd-Server: rspam04 X-HE-Tag: 1759547004-394397 X-HE-Meta: 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 lCwdfPPQ LJy+OkUDAEUiCy0k3vM8ByYXNIAb0hKiMct+Ibv7c5xUZFFLsDfYGwdtJCo8xb4arA+yHvYe1TZoNivEGact4HdNHob2Zdj3wJ6lxKm67yKUtI/gK4awf9mQ8P1C4+fPxtuWxxlAfuQ96qt3HlGQjh6hXtyydKepaB2/a1ezoC2Bym+pi34T0EDN8fk2Cjw7QMo02xhfwHucBv6aHkofI+jYgTmjNM3IqPNagz3+y9CqfiyDirv4yDKfPwiyPVSySq6UgMvAzuCpidcUJC6CL3xhoruVwWQS2DAJnkyz5iPC3/7c= 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 2025/10/4 01:05, Dev Jain wrote: > > On 02/10/25 1:02 pm, Lance Yang wrote: >> From: Lance Yang >> >> As David suggested, the PTE scanning logic in hpage_collapse_scan_pmd() >> and __collapse_huge_page_isolate() was almost duplicated. >> >> This patch cleans things up by moving all the common PTE checking logic >> into a new shared helper, thp_collapse_check_pte(). >> >> Suggested-by: David Hildenbrand >> Signed-off-by: Lance Yang >> --- > > In hpage_collapse_scan_pmd(), we enter with mmap lock held, so for > an anonymous vma, is it even possible to hit if (!folio_test_anon(folio))? Ah, indeed :) > In which case we can replace this with VM_BUG_ON_FOLIO and abstract away > till the folio_maybe_mapped_shared() block? So you meant something like this: diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 2a897cfb1d03..ef87d7fe3d50 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1374,11 +1374,7 @@ static int hpage_collapse_scan_pmd(struct mm_struct *mm, goto out_unmap; } folio = page_folio(page); - - if (!folio_test_anon(folio)) { - result = SCAN_PAGE_ANON; - goto out_unmap; - } + VM_BUG_ON_FOLIO(!folio_test_anon(folio), folio); /* * We treat a single page as shared if any part of the THP