From patchwork Mon Jun 4 23:12:37 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Dan Williams X-Patchwork-Id: 10447489 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 ECDC4600CA for ; Mon, 4 Jun 2018 23:22:37 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id DEBEE29222 for ; Mon, 4 Jun 2018 23:22:37 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id D37CD29229; Mon, 4 Jun 2018 23:22:37 +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 3ADCD29226 for ; Mon, 4 Jun 2018 23:22:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752101AbeFDXWg (ORCPT ); Mon, 4 Jun 2018 19:22:36 -0400 Received: from mga11.intel.com ([192.55.52.93]:22135 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752084AbeFDXWf (ORCPT ); Mon, 4 Jun 2018 19:22:35 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga102.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 04 Jun 2018 16:22:35 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.49,477,1520924400"; d="scan'208";a="61263549" Received: from dwillia2-desk3.jf.intel.com (HELO dwillia2-desk3.amr.corp.intel.com) ([10.54.39.16]) by fmsmga001.fm.intel.com with ESMTP; 04 Jun 2018 16:22:34 -0700 Subject: [PATCH v3 11/12] mm, memory_failure: Teach memory_failure() about dev_pagemap pages From: Dan Williams To: linux-nvdimm@lists.01.org Cc: Jan Kara , Christoph Hellwig , =?utf-8?b?SsOpcsO0bWU=?= Glisse , Matthew Wilcox , Naoya Horiguchi , Ross Zwisler , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, jack@suse.cz Date: Mon, 04 Jun 2018 16:12:37 -0700 Message-ID: <152815395775.39010.9355109660470832490.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <152815389835.39010.13253559944508110923.stgit@dwillia2-desk3.amr.corp.intel.com> References: <152815389835.39010.13253559944508110923.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 mce: Uncorrected hardware memory error in user-access at af34214200 {1}[Hardware Error]: It has been corrected by h/w and requires no further action mce: [Hardware Error]: Machine check events logged {1}[Hardware Error]: event severity: corrected Memory failure: 0xaf34214: reserved kernel page still referenced by 1 users [..] Memory failure: 0xaf34214: recovery action for reserved kernel page: Failed mce: Memory error not recovered In contrast to typical memory, dev_pagemap pages may be dax mapped. With dax there is no possibility to map in another page dynamically since dax establishes 1:1 physical address to file offset associations. Also dev_pagemap pages associated with NVDIMM / persistent memory devices can internal remap/repair addresses with poison. While memory_failure() assumes that it can discard typical poisoned pages and keep them unmapped indefinitely, dev_pagemap pages may be returned to service after the error is cleared. Teach memory_failure() to detect and handle MEMORY_DEVICE_HOST dev_pagemap pages that have poison consumed by userspace. Mark the memory as UC instead of unmapping it completely to allow ongoing access via the device driver (nd_pmem). Later, nd_pmem will grow support for marking the page back to WB when the error is cleared. Cc: Jan Kara Cc: Christoph Hellwig Cc: Jérôme Glisse Cc: Matthew Wilcox Cc: Naoya Horiguchi Cc: Ross Zwisler Signed-off-by: Dan Williams --- include/linux/mm.h | 1 mm/memory-failure.c | 145 +++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 146 insertions(+) diff --git a/include/linux/mm.h b/include/linux/mm.h index 1ac1f06a4be6..566c972e03e7 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -2669,6 +2669,7 @@ enum mf_action_page_type { MF_MSG_TRUNCATED_LRU, MF_MSG_BUDDY, MF_MSG_BUDDY_2ND, + MF_MSG_DAX, MF_MSG_UNKNOWN, }; diff --git a/mm/memory-failure.c b/mm/memory-failure.c index b6efb78ba49b..de0bc897d6e7 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -55,6 +55,7 @@ #include #include #include +#include #include #include #include "internal.h" @@ -531,6 +532,7 @@ static const char * const action_page_types[] = { [MF_MSG_TRUNCATED_LRU] = "already truncated LRU page", [MF_MSG_BUDDY] = "free buddy page", [MF_MSG_BUDDY_2ND] = "free buddy page (2nd try)", + [MF_MSG_DAX] = "dax page", [MF_MSG_UNKNOWN] = "unknown page", }; @@ -1132,6 +1134,144 @@ static int memory_failure_hugetlb(unsigned long pfn, int flags) return res; } +static unsigned long dax_mapping_size(struct address_space *mapping, + struct page *page) +{ + pgoff_t pgoff = page_to_pgoff(page); + struct vm_area_struct *vma; + unsigned long size = 0; + + i_mmap_lock_read(mapping); + xa_lock_irq(&mapping->i_pages); + /* validate that @page is still linked to @mapping */ + if (page->mapping != mapping) { + xa_unlock_irq(&mapping->i_pages); + i_mmap_unlock_read(mapping); + return 0; + } + vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) { + unsigned long address = vma_address(page, vma); + pgd_t *pgd; + p4d_t *p4d; + pud_t *pud; + pmd_t *pmd; + pte_t *pte; + + pgd = pgd_offset(vma->vm_mm, address); + if (!pgd_present(*pgd)) + continue; + p4d = p4d_offset(pgd, address); + if (!p4d_present(*p4d)) + continue; + pud = pud_offset(p4d, address); + if (!pud_present(*pud)) + continue; + if (pud_devmap(*pud)) { + size = PUD_SIZE; + break; + } + pmd = pmd_offset(pud, address); + if (!pmd_present(*pmd)) + continue; + if (pmd_devmap(*pmd)) { + size = PMD_SIZE; + break; + } + pte = pte_offset_map(pmd, address); + if (!pte_present(*pte)) + continue; + if (pte_devmap(*pte)) { + size = PAGE_SIZE; + break; + } + } + xa_unlock_irq(&mapping->i_pages); + i_mmap_unlock_read(mapping); + + return size; +} + +static int memory_failure_dev_pagemap(unsigned long pfn, int flags, + struct dev_pagemap *pgmap) +{ + struct page *page = pfn_to_page(pfn); + const bool unmap_success = true; + struct address_space *mapping; + unsigned long size; + LIST_HEAD(tokill); + int rc = -EBUSY; + loff_t start; + + /* + * Prevent the inode from being freed while we are interrogating + * the address_space, typically this would be handled by + * lock_page(), but dax pages do not use the page lock. + */ + rcu_read_lock(); + mapping = page->mapping; + if (!mapping) { + rcu_read_unlock(); + goto out; + } + if (!igrab(mapping->host)) { + mapping = NULL; + rcu_read_unlock(); + goto out; + } + rcu_read_unlock(); + + if (hwpoison_filter(page)) { + rc = 0; + goto out; + } + + switch (pgmap->type) { + case MEMORY_DEVICE_PRIVATE: + case MEMORY_DEVICE_PUBLIC: + /* + * TODO: Handle HMM pages which may need coordination + * with device-side memory. + */ + goto out; + default: + break; + } + + /* + * If the page is not mapped in userspace then report it as + * unhandled. + */ + size = dax_mapping_size(mapping, page); + if (!size) { + pr_err("Memory failure: %#lx: failed to unmap page\n", pfn); + goto out; + } + + SetPageHWPoison(page); + + /* + * Unlike System-RAM there is no possibility to swap in a + * different physical page at a given virtual address, so all + * userspace consumption of ZONE_DEVICE memory necessitates + * SIGBUS (i.e. MF_MUST_KILL) + */ + flags |= MF_ACTION_REQUIRED | MF_MUST_KILL; + collect_procs(mapping, page, &tokill, flags & MF_ACTION_REQUIRED); + + start = (page->index << PAGE_SHIFT) & ~(size - 1); + unmap_mapping_range(page->mapping, start, start + size, 0); + + kill_procs(&tokill, flags & MF_MUST_KILL, !unmap_success, ilog2(size), + mapping, page, flags); + rc = 0; +out: + if (mapping) + iput(mapping->host); + put_dev_pagemap(pgmap); + action_result(pfn, MF_MSG_DAX, rc ? MF_FAILED : MF_RECOVERED); + return rc; +} + /** * memory_failure - Handle memory failure of a page. * @pfn: Page Number of the corrupted page @@ -1154,6 +1294,7 @@ int memory_failure(unsigned long pfn, int flags) struct page *p; struct page *hpage; struct page *orig_head; + struct dev_pagemap *pgmap; int res; unsigned long page_flags; @@ -1166,6 +1307,10 @@ int memory_failure(unsigned long pfn, int flags) return -ENXIO; } + pgmap = get_dev_pagemap(pfn, NULL); + if (pgmap) + return memory_failure_dev_pagemap(pfn, flags, pgmap); + p = pfn_to_page(pfn); if (PageHuge(p)) return memory_failure_hugetlb(pfn, flags);