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, 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 4E047C43331 for ; Thu, 2 Apr 2020 02:00:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2421920675 for ; Thu, 2 Apr 2020 02:00:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733300AbgDBCAq (ORCPT ); Wed, 1 Apr 2020 22:00:46 -0400 Received: from mga02.intel.com ([134.134.136.20]:65293 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732498AbgDBCAp (ORCPT ); Wed, 1 Apr 2020 22:00:45 -0400 IronPort-SDR: mN1y/PilKLl/Lwf10aYELEpvCpGDV/YHVlK6/rz0wwJUsvB5+9WK+E3nJO344tSYdEQV/0Wq+2 kf76qLyE1yuA== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Apr 2020 19:00:45 -0700 IronPort-SDR: VtO7W3BqsOK5s4SUFIxlwyf+pUZfzge24frnaaFGaEjCrFIv3Tvvh4qvC1WKhAJZBsok67jmof MBrpBAmPnF2Q== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.72,333,1580803200"; d="scan'208";a="240690407" Received: from yhuang-dev.sh.intel.com ([10.239.159.23]) by fmsmga007.fm.intel.com with ESMTP; 01 Apr 2020 19:00:41 -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 -V2] /proc/PID/smaps: Add PMD migration entry parsing Date: Thu, 2 Apr 2020 10:00:31 +0800 Message-Id: <20200402020031.1611223-1-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: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 processing is added. Before the patch, for a fully populated 400 MB anonymous VMA, sometimes some THP pages under migration may be lost as follows. 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: "Jérôme Glisse" Cc: Yang Shi --- 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 nuking kernel for this. --- fs/proc/task_mmu.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-) diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 8d382d4ec067..9c72f9ce2dd8 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -546,10 +546,19 @@ static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr, struct mem_size_stats *mss = walk->private; struct vm_area_struct *vma = walk->vma; bool locked = !!(vma->vm_flags & VM_LOCKED); - struct page *page; + struct page *page = NULL; - /* FOLL_DUMP will return -EFAULT on huge zero page */ - page = follow_trans_huge_pmd(vma, addr, pmd, FOLL_DUMP); + if (pmd_present(*pmd)) { + /* FOLL_DUMP will return -EFAULT on huge zero page */ + page = follow_trans_huge_pmd(vma, addr, pmd, FOLL_DUMP); + } else if (unlikely(thp_migration_supported() && is_swap_pmd(*pmd))) { + swp_entry_t entry = pmd_to_swp_entry(*pmd); + + if (is_migration_entry(entry)) + page = migration_entry_to_page(entry); + else + VM_WARN_ON_ONCE(1); + } if (IS_ERR_OR_NULL(page)) return; if (PageAnon(page)) @@ -578,8 +587,7 @@ static int smaps_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, ptl = 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; } -- 2.25.0