From: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
To: linux-mm@kvack.org, linux-kernel@vger.kernel.org
Cc: Michal Hocko <mhocko@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Mike Kravetz <mike.kravetz@oracle.com>,
xishi.qiuxishi@alibaba-inc.com,
Laurent Dufour <ldufour@linux.vnet.ibm.com>
Subject: [RFC][PATCH v1 02/11] mm: soft-offline: add missing error check of set_hwpoison_free_buddy_page()
Date: Fri, 9 Nov 2018 15:47:06 +0900 [thread overview]
Message-ID: <1541746035-13408-3-git-send-email-n-horiguchi@ah.jp.nec.com> (raw)
In-Reply-To: <1541746035-13408-1-git-send-email-n-horiguchi@ah.jp.nec.com>
set_hwpoison_free_buddy_page() could fail, then the target page is
finally not isolated, so it's better to report -EBUSY for userspace
to know the failure and chance of retry.
And for consistency, this patch moves set_hwpoison_free_buddy_page()
in unmap_and_move() to __soft_offline_page().
Fixes: 6bc9b56433b7 ("mm: fix race on soft-offlining free huge pages")
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
---
mm/memory-failure.c | 15 ++++++++++++---
mm/migrate.c | 9 ---------
2 files changed, 12 insertions(+), 12 deletions(-)
diff --git v4.19-mmotm-2018-10-30-16-08/mm/memory-failure.c v4.19-mmotm-2018-10-30-16-08_patched/mm/memory-failure.c
index 9f09bf3..11e283e 100644
--- v4.19-mmotm-2018-10-30-16-08/mm/memory-failure.c
+++ v4.19-mmotm-2018-10-30-16-08_patched/mm/memory-failure.c
@@ -1719,14 +1719,18 @@ static int soft_offline_huge_page(struct page *page, int flags)
/*
* We set PG_hwpoison only when the migration source hugepage
* was successfully dissolved, because otherwise hwpoisoned
- * hugepage remains on free hugepage list, then userspace will
- * find it as SIGBUS by allocation failure. That's not expected
- * in soft-offlining.
+ * hugepage remains on free hugepage list. The allocator ignores
+ * such a hwpoisoned page so it's never allocated, but it could
+ * kill a process because of no-memory rather than hwpoison.
+ * Soft-offline never impacts the userspace, so this is
+ * undesired.
*/
ret = dissolve_free_huge_page(page);
if (!ret) {
if (set_hwpoison_free_buddy_page(page))
num_poisoned_pages_inc();
+ else
+ ret = -EBUSY;
}
}
return ret;
@@ -1804,6 +1808,11 @@ static int __soft_offline_page(struct page *page, int flags)
pfn, ret, page->flags, &page->flags);
if (ret > 0)
ret = -EIO;
+ } else {
+ if (set_hwpoison_free_buddy_page(page))
+ num_poisoned_pages_inc();
+ else
+ ret = -EBUSY;
}
} else {
pr_info("soft offline: %#lx: isolation failed: %d, page count %d, type %lx (%pGp)\n",
diff --git v4.19-mmotm-2018-10-30-16-08/mm/migrate.c v4.19-mmotm-2018-10-30-16-08_patched/mm/migrate.c
index f7e4bfd..1742372 100644
--- v4.19-mmotm-2018-10-30-16-08/mm/migrate.c
+++ v4.19-mmotm-2018-10-30-16-08_patched/mm/migrate.c
@@ -1199,15 +1199,6 @@ static ICE_noinline int unmap_and_move(new_page_t get_new_page,
*/
if (rc == MIGRATEPAGE_SUCCESS) {
put_page(page);
- if (reason == MR_MEMORY_FAILURE) {
- /*
- * Set PG_HWPoison on just freed page
- * intentionally. Although it's rather weird,
- * it's how HWPoison flag works at the moment.
- */
- if (set_hwpoison_free_buddy_page(page))
- num_poisoned_pages_inc();
- }
} else {
if (rc != -EAGAIN) {
if (likely(!__PageMovable(page))) {
--
2.7.0
next prev parent reply other threads:[~2018-11-09 6:47 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-09 6:47 [PATCH RFC v1 00/11] hwpoison improvement part 1 Naoya Horiguchi
2018-11-09 6:47 ` [RFC][PATCH v1 01/11] mm: hwpoison: cleanup unused PageHuge() check Naoya Horiguchi
2018-11-09 9:52 ` Anshuman Khandual
2018-11-09 6:47 ` Naoya Horiguchi [this message]
2018-11-09 10:20 ` [RFC][PATCH v1 02/11] mm: soft-offline: add missing error check of set_hwpoison_free_buddy_page() Anshuman Khandual
2018-11-13 0:16 ` Naoya Horiguchi
2018-11-14 8:53 ` Anshuman Khandual
2018-11-09 6:47 ` [RFC][PATCH v1 03/11] mm: move definition of num_poisoned_pages_inc/dec to include/linux/mm.h Naoya Horiguchi
2018-11-09 10:28 ` Anshuman Khandual
2018-11-13 0:17 ` Naoya Horiguchi
2018-11-09 6:47 ` [RFC][PATCH v1 04/11] mm: madvise: call soft_offline_page() without MF_COUNT_INCREASED Naoya Horiguchi
2018-11-09 10:46 ` Anshuman Khandual
2018-11-13 0:18 ` Naoya Horiguchi
2018-11-09 6:47 ` [RFC][PATCH v1 05/11] mm: hwpoison-inject: don't pin for hwpoison_filter() Naoya Horiguchi
2018-11-09 6:47 ` [RFC][PATCH v1 06/11] mm: hwpoison: remove MF_COUNT_INCREASED Naoya Horiguchi
2018-11-09 6:47 ` [RFC][PATCH v1 07/11] mm: remove flag argument from soft offline functions Naoya Horiguchi
2018-11-09 6:47 ` [RFC][PATCH v1 08/11] mm: soft-offline: isolate error pages from buddy freelist Naoya Horiguchi
2018-11-09 6:47 ` [RFC][PATCH v1 09/11] mm: hwpoison: apply buddy page handling code to hard-offline Naoya Horiguchi
2018-11-09 6:47 ` [RFC][PATCH v1 10/11] mm: clear PageHWPoison in memory hotremove Naoya Horiguchi
2018-11-13 1:32 ` Naoya Horiguchi
2018-11-09 6:47 ` [RFC][PATCH v1 11/11] mm: hwpoison: introduce clear_hwpoison_free_buddy_page() Naoya Horiguchi
2018-11-09 11:33 ` Anshuman Khandual
2018-11-13 0:19 ` Naoya Horiguchi
2018-11-14 8:23 ` Anshuman Khandual
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1541746035-13408-3-git-send-email-n-horiguchi@ah.jp.nec.com \
--to=n-horiguchi@ah.jp.nec.com \
--cc=akpm@linux-foundation.org \
--cc=ldufour@linux.vnet.ibm.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mhocko@kernel.org \
--cc=mike.kravetz@oracle.com \
--cc=xishi.qiuxishi@alibaba-inc.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).