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 X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B2415C2D0E8 for ; Fri, 3 Apr 2020 12:31:56 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 8249E2077D for ; Fri, 3 Apr 2020 12:31:56 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8249E2077D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 2AB808E0008; Fri, 3 Apr 2020 08:31:56 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 25B848E0007; Fri, 3 Apr 2020 08:31:56 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 14AC18E0008; Fri, 3 Apr 2020 08:31:56 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0211.hostedemail.com [216.40.44.211]) by kanga.kvack.org (Postfix) with ESMTP id F217E8E0007 for ; Fri, 3 Apr 2020 08:31:55 -0400 (EDT) Received: from smtpin04.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id B293F2491 for ; Fri, 3 Apr 2020 12:31:55 +0000 (UTC) X-FDA: 76666480590.04.jam38_10be545940e36 X-HE-Tag: jam38_10be545940e36 X-Filterd-Recvd-Size: 5808 Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by imf29.hostedemail.com (Postfix) with ESMTP for ; Fri, 3 Apr 2020 12:31:54 +0000 (UTC) IronPort-SDR: UMM3a4VH5QQ7SdY0Z8Vn6Z2MAGifSoCf0ZIQv269cc88I3PhQy+TeD/+SeBmRMkKZeW4RO6z2Y F5iQVkV7prew== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Apr 2020 05:31:53 -0700 IronPort-SDR: nI2olLeXrFo1lRBhvElCdhDMR3vtppxqaBq/NacGGUrVv6B7DI8vpIsFPJ7Rq3yQb2ITRGkori D5E/TseIovkQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.72,339,1580803200"; d="scan'208";a="273934294" Received: from unknown (HELO yhuang-dev.sh.intel.com) ([10.239.159.23]) by fmsmga004.fm.intel.com with ESMTP; 03 Apr 2020 05:31:50 -0700 From: "Huang, Ying" To: Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Huang Ying , Zi Yan , Andrea Arcangeli , "Kirill A . Shutemov" , Vlastimil Babka , Alexey Dobriyan , Michal Hocko , Konstantin Khlebnikov , =?UTF-8?q?J=C3=A9r=C3=B4me=20Glisse?= , Yang Shi Subject: [PATCH -V3] /proc/PID/smaps: Add PMD migration entry parsing Date: Fri, 3 Apr 2020 20:30:59 +0800 Message-Id: <20200403123059.1846960-1-ying.huang@intel.com> X-Mailer: git-send-email 2.25.0 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable 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: From: Huang Ying Now, when read /proc/PID/smaps, the PMD migration entry in page table is = simply ignored. To improve the accuracy of /proc/PID/smaps, its parsing and pro= cessing is added. To test the patch, we run pmbench to eat 400 MB memory in background, the= n run /usr/bin/migratepages and `cat /proc/PID/smaps` every second. The issue = as follows can be reproduced within 60 seconds. Before the patch, for the fully populated 400 MB anonymous VMA, some THP = pages under migration may be lost as below. 7f3f6a7e5000-7f3f837e5000 rw-p 00000000 00:00 0 Size: 409600 kB KernelPageSize: 4 kB MMUPageSize: 4 kB Rss: 407552 kB Pss: 407552 kB Shared_Clean: 0 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 407552 kB Referenced: 301056 kB Anonymous: 407552 kB LazyFree: 0 kB AnonHugePages: 405504 kB ShmemPmdMapped: 0 kB FilePmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 0 kB THPeligible: 1 VmFlags: rd wr mr mw me ac After the patch, it will be always, 7f3f6a7e5000-7f3f837e5000 rw-p 00000000 00:00 0 Size: 409600 kB KernelPageSize: 4 kB MMUPageSize: 4 kB Rss: 409600 kB Pss: 409600 kB Shared_Clean: 0 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 409600 kB Referenced: 294912 kB Anonymous: 409600 kB LazyFree: 0 kB AnonHugePages: 407552 kB ShmemPmdMapped: 0 kB FilePmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 0 kB THPeligible: 1 VmFlags: rd wr mr mw me ac Signed-off-by: "Huang, Ying" Reviewed-by: Zi Yan Cc: Andrea Arcangeli Cc: Kirill A. Shutemov Cc: Vlastimil Babka Cc: Alexey Dobriyan Cc: Michal Hocko Cc: Konstantin Khlebnikov Cc: "J=C3=A9r=C3=B4me Glisse" Cc: Yang Shi --- v3: - Revised patch description and remove VM_WARN_ON_ONCE() per Michal's com= ments v2: - Use thp_migration_supported() in condition to reduce code size if THP migration isn't enabled. - Replace VM_BUG_ON() with VM_WARN_ON_ONCE(), it's not necessary to nukin= g kernel for this. --- fs/proc/task_mmu.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 8d382d4ec067..36dc7417c0df 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -546,10 +546,17 @@ static void smaps_pmd_entry(pmd_t *pmd, unsigned lo= ng addr, struct mem_size_stats *mss =3D walk->private; struct vm_area_struct *vma =3D walk->vma; bool locked =3D !!(vma->vm_flags & VM_LOCKED); - struct page *page; + struct page *page =3D NULL; + + if (pmd_present(*pmd)) { + /* FOLL_DUMP will return -EFAULT on huge zero page */ + page =3D follow_trans_huge_pmd(vma, addr, pmd, FOLL_DUMP); + } else if (unlikely(thp_migration_supported() && is_swap_pmd(*pmd))) { + swp_entry_t entry =3D pmd_to_swp_entry(*pmd); =20 - /* FOLL_DUMP will return -EFAULT on huge zero page */ - page =3D follow_trans_huge_pmd(vma, addr, pmd, FOLL_DUMP); + if (is_migration_entry(entry)) + page =3D migration_entry_to_page(entry); + } if (IS_ERR_OR_NULL(page)) return; if (PageAnon(page)) @@ -578,8 +585,7 @@ static int smaps_pte_range(pmd_t *pmd, unsigned long = addr, unsigned long end, =20 ptl =3D pmd_trans_huge_lock(pmd, vma); if (ptl) { - if (pmd_present(*pmd)) - smaps_pmd_entry(pmd, addr, walk); + smaps_pmd_entry(pmd, addr, walk); spin_unlock(ptl); goto out; } --=20 2.25.0