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 E36FBC3DA7A for ; Wed, 14 Oct 2026 17:12:30 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 1E1096B00A4; Wed, 14 Oct 2026 13:12:28 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 1B8E86B00A5; Wed, 14 Oct 2026 13:12:28 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0803A6B00A6; Wed, 14 Oct 2026 13:12:28 -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 D6E8E6B00A4 for ; Wed, 14 Oct 2026 13:12:27 -0400 (EDT) Received: from smtpin30.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 4F35714068A for ; Wed, 14 Oct 2026 17:12:27 +0000 (UTC) X-FDA: 85321875534.30.3E5D068 Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf24.hostedemail.com (Postfix) with ESMTP id 5142F18000A for ; Wed, 14 Oct 2026 17:12:25 +0000 (UTC) Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b="UP0d10/7"; spf=pass (imf24.hostedemail.com: domain of kas@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=kas@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1791997945; 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-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=ghheLVaJ/gX6nEonLl9gHN6oOmaGkKtSAgsx7MmKQ3g=; b=HRyhXfcErnDNyMVbZDoKXohb0ADtwS9PvaTWVPHTAloYa6TAfBDF4nCxg2stk8Lg0pg9Hf BlUDhKaISlHv34TbTmwJpNQMWsPGLTUwx2SjGu+sT6YEh+SiAM6j88llooiaF3OBka+lHx +EWxCtyoUvEkhQioK0k/YrXjSiGWycI= ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1791997945; b=7eWnvGNhHx4pqEjz+y0K9ryUsi6QdMEPCYBkIajLGZByBHSNMgvvINzjOtRuoCsZxWJOu9 LAUoKLqoC1WjquEJbRkuj40145+/QznzuaPgQ+htGj31Uty9R1yk/VA6Xb5db6nX1W4U69 lgjMeSara9/XGKXPk6QXYRGC2UMzpMc= ARC-Authentication-Results: i=1; imf24.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b="UP0d10/7"; spf=pass (imf24.hostedemail.com: domain of kas@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=kas@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id DDACD60A66; Wed, 14 Oct 2026 17:12:24 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 32C421F000C5; Wed, 14 Oct 2026 17:12:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791997944; bh=ghheLVaJ/gX6nEonLl9gHN6oOmaGkKtSAgsx7MmKQ3g=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=UP0d10/7ajJS7uDLbamTgU+u3mYlInh1ovqKT9AsZnSfLXL86NU5zXtC6bucBOFmj x8bTEPjZigb7Uoyp4/1Ml8bqcnGi68WfEA1HxEyb75ziiRBiHqf74r4I9io0+/X50d QfF6bYbrGTaLnJOMnpPFW1VsmoHrrMYUEpP62QNpwxvmayXJilUZpmUe+L0h17q09D HdQK7UO28IWCXXIf3BIXMd7yADj3SHGRZWCkEm66K7uNS1WHL3huReMn2BD0gaGZQz XaQABApnybxpv0NmBmOQW7KgonSK8wsYrvtrl1HB1eaq62iIlp5vHPovvSxXOv2Fv3 qgu31KRDDqP4g== Received: from phl-compute-01.internal (phl-compute-01.internal [10.202.2.41]) by mailfauth.ams.internal (Postfix) with ESMTP id 78FF0198003A; Wed, 14 Oct 2026 13:12:20 -0400 (EDT) Received: from phl-frontend-04 ([10.202.2.163]) by phl-compute-01.internal (MEProxy); Wed, 14 Oct 2026 13:12:21 -0400 X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: dmFkZTFwiWz5xia+xtfntThlm+O9tjGeMfOg5p/zL8VYVtsXULwc8jTBr08jVHcQEsbhxK TMndqLDMMqjXpLlrcd2DNZw/axYZ8/70s9fvQ++ndGURDbYnj9+jE2pWTYgDyBIy7T7c+g 1FLBAJg8ViAMIIR0WeG0kvIsAspTPwKIIiDbhgldWlfNpOyYl1MvyWfNinOTpMZ090jALU i/RcA+fWUVj+1PXpLp5EB/t8KfPsMi6C8/Rktwnc+ddxJOjK8acgquDVoYbmvcpcPF5ZbL fP/sPU/D8T1xJDgjYxA59CqeA0LY0DgbH9ErVKg6G21806a9Ona+7e7I9CP057PccJyjlb RJunY59V05jTYe7Q7N4LTguEDLhUxjZiw+9otdXTimDDyUnj/gBdnPlQgwkrbck+IfIPYW 82hBftchyULhlpGWaSd1L2FLS0pGRNApT7nCyS5XHIeZ0QXGmAH7sRzsYz2X38IrI1Tkml qSo6jIEdsQYRTZnc0y2csIkaVRTjJEo0YqabWJqMGbr3SvFF2BsTqncd7voLfHu9wXlF1X FIX2YhqHwn8wvI7aJ4OvzR5Avh4OYZgSiqs8jHyLD4H6twj8GOLejLN13KV054UXgAZ7bi Ujr5U7D9yHzErSrTQhcNGLi/7VORFxIACHkANoSzwQlIiuc3HePCeVucyR1A X-ME-Proxy: Feedback-ID: i10464835:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Wed, 14 Oct 2026 13:12:19 -0400 (EDT) From: "Kiryl Shutsemau (Meta)" To: Andrew Morton , David Hildenbrand , Lorenzo Stoakes , Zi Yan , Baolin Wang Cc: "Kiryl Shutsemau (Meta)" , linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@meta.com, "Liam R. Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Usama Arif , Vlastimil Babka , Jann Horn Subject: [PATCH v5 8/9] mm/collapse: call collapse_file() from collapse_single_pmd() Date: Wed, 14 Oct 2026 18:11:41 +0100 Message-ID: <20261014171145.3292736-9-kas@kernel.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20261014171145.3292736-1-kas@kernel.org> References: <20261014171145.3292736-1-kas@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 5142F18000A X-Rspam-User: X-Stat-Signature: uc94x5m4dj5nt5qcr74kgzo5ux4fmfd1 X-HE-Tag: 1791997945-637949 X-HE-Meta: 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 8M8wLsGo naX17wM/dqYp1nLvNsBCGyOML7B+iDDP4api6fB4SsZPcHFeNiVKG2kaNrI7rakK13Y04t2p/14CCedhCn4ZV14+dXeYN/of6dHv2Rzm6+3jwnRgvnm43G07Mo6PNn+xG9Fe74VSYkbWocbnQYRAUmf6gQGFqTGN4i50pzYybBw3+CV4Vel4ANQvA+BxOcymXMjnYjmoyTKxUZ3h+oOvxf0jLwFpRonIQLBlbvkE33QE9xEuN5td+3VgY+ugObPKa6nk9QGcJWVpJH/byRMBLNgem7Qt415bvjSYfDBPJxJ8ET5zqyoz3XdUdF4db70i8s1xY2g2fJD2GBQY= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: collapse_scan_file() reads the page cache to decide whether a table is worth collapsing and, when it is, calls collapse_file() itself. The caller cannot get between the decision and the collapse. Move the collapse_file() call up into collapse_single_pmd(), so the scan stops at the decision. Two things change with it. The writeback retry re-runs collapse_file() alone instead of rescanning first; collapse_file() repeats the scan's checks under the page cache lock anyway. And mm_khugepaged_scan_file fires before the collapse, so for an accepted table its status reads SCAN_SUCCEED; what the collapse made of the table is for mm_khugepaged_collapse_file to report. Preparation for splitting a collapse into a scan under mmap_lock and a run without it. The file scan has to stop where the anonymous one will. Assisted-by: LLM Acked-by: David Hildenbrand (Arm) Reviewed-by: Zi Yan Signed-off-by: Kiryl Shutsemau (Meta) --- mm/khugepaged.c | 21 +++++++++++++-------- 1 file changed, 13 insertions(+), 8 deletions(-) diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 60ec7e80d554..89a4c3f5a91c 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -2737,13 +2737,9 @@ static enum scan_result collapse_scan_file(struct mm_struct *mm, else cc->progress += HPAGE_PMD_NR; - if (result == SCAN_SUCCEED) { - if (present < HPAGE_PMD_NR - max_ptes_none) { - result = SCAN_EXCEED_NONE_PTE; - count_vm_event(THP_SCAN_EXCEED_NONE_PTE); - } else { - result = collapse_file(mm, addr, file, start, cc); - } + if (result == SCAN_SUCCEED && present < HPAGE_PMD_NR - max_ptes_none) { + result = SCAN_EXCEED_NONE_PTE; + count_vm_event(THP_SCAN_EXCEED_NONE_PTE); } trace_mm_khugepaged_scan_file(mm, failed_pfn, file, present, swap, result); @@ -2774,8 +2770,16 @@ static enum scan_result collapse_single_pmd(unsigned long addr, mmap_read_unlock(mm); *lock_dropped = true; -retry: + + /* + * SCAN_PTE_MAPPED_HUGEPAGE is work too: the page cache already holds + * the PMD folio, and only the PTE table is left to retract. + */ result = collapse_scan_file(mm, addr, file, pgoff, cc); + if (result != SCAN_SUCCEED) + goto put; +retry: + result = collapse_file(mm, addr, file, pgoff, cc); /* Dirty pages are worth a writeback and one more try, if asked for */ if (cc->policy.file_writeback_dirty && result == SCAN_PAGE_DIRTY_OR_WRITEBACK && @@ -2787,6 +2791,7 @@ static enum scan_result collapse_single_pmd(unsigned long addr, triggered_wb = true; goto retry; } +put: fput(file); if (result == SCAN_PTE_MAPPED_HUGEPAGE) { -- 2.54.0