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 48E52CD8CB2 for ; Thu, 11 Jun 2026 06:06:53 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 604F26B008C; Thu, 11 Jun 2026 02:06:52 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 5DBD26B0092; Thu, 11 Jun 2026 02:06:52 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5190C6B0093; Thu, 11 Jun 2026 02:06:52 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 414646B008C for ; Thu, 11 Jun 2026 02:06:52 -0400 (EDT) Received: from smtpin25.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay10.hostedemail.com (Postfix) with ESMTP id BC732C1D5C for ; Thu, 11 Jun 2026 06:06:51 +0000 (UTC) X-FDA: 84866598222.25.06148F0 Received: from out-173.mta1.migadu.com (out-173.mta1.migadu.com [95.215.58.173]) by imf30.hostedemail.com (Postfix) with ESMTP id 9403580003 for ; Thu, 11 Jun 2026 06:06:49 +0000 (UTC) Authentication-Results: imf30.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=ftEQ4RdY; spf=pass (imf30.hostedemail.com: domain of lance.yang@linux.dev designates 95.215.58.173 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=1781158010; 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=VY6cPLdBFMgAfHoRWeR+QE2M/b9diN2t5Veaeaq+jOM=; b=PN4JkLeP39OJCn4KFFWNBaYeOl6plevZAgZgYbTZ6MaljDR9s3es0DWi/gMFRGTxGRFNpK kFIjwNrfDzMF2TM2GsviViWBASjSdG9UnIoT8JRy6pO06COOaVv681J5AiZAps/cbaPlJG nQCJhKfJCa+89/GC5kJ92Rt/7EoG6HE= ARC-Authentication-Results: i=1; imf30.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=ftEQ4RdY; spf=pass (imf30.hostedemail.com: domain of lance.yang@linux.dev designates 95.215.58.173 as permitted sender) smtp.mailfrom=lance.yang@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1781158010; b=FpDCS5llHgvX3lyQxdj2Qw7Yw//CNUo/2zZWWnvtliXZrRsQkknVcQexZfv/W8WEtZvM7V CHaIrGULKVLLMkm2Z9GIrKNmZmW/BGvstBf+V3CQDj9dmLMlNXSkEnXzCdmbt4yarrJkNU SbR2aBxkFUKhyf+3s1RMwuOSZthxz9o= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1781158007; 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=VY6cPLdBFMgAfHoRWeR+QE2M/b9diN2t5Veaeaq+jOM=; b=ftEQ4RdY3JzZb61UAxo9N15nCfYeH1ESPtYqnyAjeynqSBo43LkPMTTqO9JcKjiEFqHWVF S69PLmCZYqmxG/x0wEF7QkOO2QdjEdRsGD0fs8us2gXWZ7jVGOYvplIaqm9zA46Hyvejsb buz1f6cyS40AP9fHbkhYLyXLvaPrPKA= From: Lance Yang To: baolin.wang@linux.alibaba.com Cc: akpm@linux-foundation.org, david@kernel.org, ljs@kernel.org, hughd@google.com, willy@infradead.org, ziy@nvidia.com, liam@infradead.org, npache@redhat.com, ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org, lance.yang@linux.dev, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH v2 04/11] mm: khugepaged: add shmem mTHP collapse support Date: Thu, 11 Jun 2026 14:06:19 +0800 Message-Id: <20260611060619.94738-1-lance.yang@linux.dev> In-Reply-To: <3895c09794739bbfae99d9e021ffacf8a51fb8e2.1781083630.git.baolin.wang@linux.alibaba.com> References: <3895c09794739bbfae99d9e021ffacf8a51fb8e2.1781083630.git.baolin.wang@linux.alibaba.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 9403580003 X-Stat-Signature: r1ttnm9w157q5mm77s7em3amq56tcqtd X-Rspam-User: X-HE-Tag: 1781158009-778028 X-HE-Meta: U2FsdGVkX1/0xWaXvDmKQmUZU5WH30xQo9pK8SC942p39CZsaL5JbcwKxEnJ/TQ2Alz12oXT4A3unN9XVlvn00J7tcnEwor0QQpq5CL7UgZW/fXFSu+gaVFhE/mzI13kc9iugZAWPBrwwac3bBgVlt17NZeZAsJysrlfIeb3hKiFI6ICiqaIaWltoh2GhKrX5IMik9peeIi/y2da3MwjkZ7LdTQxMl/ya2ro9SzYw4DK0sybbmC4N490C2M7drL3o4Unmh+cA0GDjYaI2E7hVGKiJuE7aSro3ng+iy/fxfl2sT6Bc5XpEYXCuILkzIKeICI2Uex3SN15FSJc+MUOawtcDx+oZP8kRROuRXCdP7QEeXVEHDODbJq10KfoPoZQlPcd91QKNRxb/+6kpwQaVgxkYYfghTFXzlgidootwkO3fuOYhZb/AJIW1Nn7yCnl/9Y3RcvMdDTbB1zY64loL9GXRK7/SaCcuI4p7CWpBEZ/+6R9F1tWDNbKUZaaU+3PTim8rtBruGyPbkaZORdplv0FX/1Byj3vjWz/2I/aLUrI0q2Tl7kTbHaF9I89/ekwvQ948EaXjAoEdDzbXvSNhGZb8ucOZh5NBhr5sBDsDaSrmyNQZJXeyxFrztTpM6xUeCVbKneT5s7I+66ju0bffSLPJWfaOiiP+ALYX4BOH5eYYRA81cPY6aZEALU8tajNjGVYWFEKNagwwEKOGadCt2aRdn+xM5JvbAWeyAi9qmoZAYDOzmHSZphvutBSByY0e01MOFkN9uIIoSDj0ZsBQPjNEAaLhj7gSSfA5BCZu/+JdvoWGU5JTVKZ8jnBnNgcZsvkvYp7Mg0YDY/fes7kmrQAZOxwGQX6tIuPOk4xatyWinSPGTRkkZC+RN+3FLQnG3c26fz90/b1uSUp6X2I+Wd9u9YL5PE45NW99cQB2vXf6jLoSN5mk43yk6Fxc+4QCteobQpP08B4ND5N/H/ 99yP87gx WgSK5FWgeHqLp2oW43Qf9qnsr7xRgjLRV+BPDr02oVFFqe0cGkAybYpXKJiJQ2QIGloS3lOZCEimR101ea2dHlkihm74vfgBi16jZi2oRQDESAPJ9mT/m0rTvrRv18aQY9gqHHA8KsV3aTpU7TiDsUma5DEnTiXWDCKQQqfjJeUf7k8NS3datSgEDZbqlKq6bs6E8HSVd7x9eQYbj8PFfzP/uRA== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, Jun 10, 2026 at 06:29:12PM +0800, Baolin Wang wrote: [...] >@@ -2768,15 +2827,23 @@ 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, HPAGE_PMD_ORDER); >- } >+ if (result != SCAN_SUCCEED) >+ goto out; >+ >+ if (present < HPAGE_PMD_NR - max_ptes_none) { >+ result = SCAN_EXCEED_NONE_PTE; >+ count_vm_event(THP_SCAN_EXCEED_NONE_PTE); >+ count_mthp_stat(HPAGE_PMD_ORDER, >+ MTHP_STAT_COLLAPSE_EXCEED_NONE); >+ goto out; > } > >+ result = mthp_collapse(mm, file, start, addr, 0, 0, cc, enabled_orders); Feels like the second 0 wants to be "swap", no? >+ if (result == SCAN_SUCCEED && !cc->is_khugepaged) { >+ /* If MADV_COLLAPSE, adjust result to call collapse_pte_mapped_thp(). */ >+ result = SCAN_PTE_MAPPED_HUGEPAGE; >+ } >+out: > trace_mm_khugepaged_scan_file(mm, folio, file, present, swap, result); > return result; > } >@@ -2808,7 +2875,7 @@ static enum scan_result collapse_single_pmd(unsigned long addr, > mmap_read_unlock(mm); > *lock_dropped = true; > retry: >- result = collapse_scan_file(mm, addr, file, pgoff, cc); >+ result = collapse_scan_file(mm, vma, addr, file, pgoff, cc); > > /* > * For MADV_COLLAPSE, when encountering dirty pages, try to writeback, >-- >2.47.3 > >