From patchwork Fri Jun 8 23:50:52 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dan Williams X-Patchwork-Id: 10455353 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id AFED660234 for ; Sat, 9 Jun 2018 00:00:57 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A0B2929563 for ; Sat, 9 Jun 2018 00:00:57 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 9F275294D1; Sat, 9 Jun 2018 00:00:57 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00, MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C921E2969C for ; Sat, 9 Jun 2018 00:00:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753220AbeFIAAu (ORCPT ); Fri, 8 Jun 2018 20:00:50 -0400 Received: from mga01.intel.com ([192.55.52.88]:12674 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753099AbeFIAAu (ORCPT ); Fri, 8 Jun 2018 20:00:50 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 08 Jun 2018 17:00:49 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.49,492,1520924400"; d="scan'208";a="235934676" Received: from dwillia2-desk3.jf.intel.com (HELO dwillia2-desk3.amr.corp.intel.com) ([10.54.39.16]) by fmsmga006.fm.intel.com with ESMTP; 08 Jun 2018 17:00:49 -0700 Subject: [PATCH v4 06/12] mm, madvise_inject_error: Let memory_failure() optionally take a page reference From: Dan Williams To: linux-nvdimm@lists.01.org Cc: Michal Hocko , Naoya Horiguchi , hch@lst.de, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, jack@suse.cz Date: Fri, 08 Jun 2018 16:50:52 -0700 Message-ID: <152850185265.38390.2828727053299635327.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <152850182079.38390.8280340535691965744.stgit@dwillia2-desk3.amr.corp.intel.com> References: <152850182079.38390.8280340535691965744.stgit@dwillia2-desk3.amr.corp.intel.com> User-Agent: StGit/0.18-2-gc94f MIME-Version: 1.0 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The madvise_inject_error() routine uses get_user_pages() to lookup the pfn and other information for injected error, but it does not release that pin. The assumption is that failed pages should be taken out of circulation. However, for dax mappings it is not possible to take pages out of circulation since they are 1:1 physically mapped as filesystem blocks, or device-dax capacity. They also typically represent persistent memory which has an error clearing capability. In preparation for adding a special handler for dax mappings, shift the responsibility of taking the page reference to memory_failure(). I.e. drop the page reference and do not specify MF_COUNT_INCREASED to memory_failure(). Cc: Michal Hocko Cc: Naoya Horiguchi Signed-off-by: Dan Williams --- mm/madvise.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) diff --git a/mm/madvise.c b/mm/madvise.c index 4d3c922ea1a1..b731933dddae 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -631,11 +631,13 @@ static int madvise_inject_error(int behavior, for (; start < end; start += PAGE_SIZE << order) { + unsigned long pfn; int ret; ret = get_user_pages_fast(start, 1, 0, &page); if (ret != 1) return ret; + pfn = page_to_pfn(page); /* * When soft offlining hugepages, after migrating the page @@ -651,17 +653,27 @@ static int madvise_inject_error(int behavior, if (behavior == MADV_SOFT_OFFLINE) { pr_info("Soft offlining pfn %#lx at process virtual address %#lx\n", - page_to_pfn(page), start); + pfn, start); ret = soft_offline_page(page, MF_COUNT_INCREASED); if (ret) return ret; continue; } + pr_info("Injecting memory failure for pfn %#lx at process virtual address %#lx\n", - page_to_pfn(page), start); + pfn, start); + + ret = memory_failure(pfn, 0); + + /* + * Drop the page reference taken by get_user_pages_fast(). In + * the absence of MF_COUNT_INCREASED the memory_failure() + * routine is responsible for pinning the page to prevent it + * from being released back to the page allocator. + */ + put_page(page); - ret = memory_failure(page_to_pfn(page), MF_COUNT_INCREASED); if (ret) return ret; }