From: Oscar Salvador <osalvador@suse.de>
To: n-horiguchi@ah.jp.nec.com
Cc: mhocko@kernel.org, mike.kravetz@oracle.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, Oscar Salvador <osalvador@suse.de>
Subject: [RFC PATCH v2 02/16] mm,madvise: call soft_offline_page() without MF_COUNT_INCREASED
Date: Thu, 17 Oct 2019 16:21:09 +0200 [thread overview]
Message-ID: <20191017142123.24245-3-osalvador@suse.de> (raw)
In-Reply-To: <20191017142123.24245-1-osalvador@suse.de>
From: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
The call to get_user_pages_fast is only to get the pointer to a struct
page of a given address, pinning it is memory-poisoning handler's job,
so drop the refcount grabbed by get_user_pages_fast
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Oscar Salvador <osalvador@suse.de>
---
mm/madvise.c | 24 ++++++++++++------------
1 file changed, 12 insertions(+), 12 deletions(-)
diff --git a/mm/madvise.c b/mm/madvise.c
index 2be9f3fdb05e..89ed9a22ff4f 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -878,16 +878,24 @@ static int madvise_inject_error(int behavior,
*/
order = compound_order(compound_head(page));
- if (PageHWPoison(page)) {
- put_page(page);
+ /*
+ * The get_user_pages_fast() is just to get the pfn of the
+ * given address, and the refcount has nothing to do with
+ * what we try to test, so it should be released immediately.
+ * This is racy but it's intended because the real hardware
+ * errors could happen at any moment and memory error handlers
+ * must properly handle the race.
+ */
+ put_page(page);
+
+ if (PageHWPoison(page))
continue;
- }
if (behavior == MADV_SOFT_OFFLINE) {
pr_info("Soft offlining pfn %#lx at process virtual address %#lx\n",
pfn, start);
- ret = soft_offline_page(page, MF_COUNT_INCREASED);
+ ret = soft_offline_page(page, 0);
if (ret)
return ret;
continue;
@@ -895,14 +903,6 @@ static int madvise_inject_error(int behavior,
pr_info("Injecting memory failure for pfn %#lx at process virtual address %#lx\n",
pfn, start);
-
- /*
- * 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(pfn, 0);
if (ret)
return ret;
--
2.12.3
next prev parent reply other threads:[~2019-10-17 14:22 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-17 14:21 [RFC PATCH v2 00/16] Hwpoison rework {hard,soft}-offline Oscar Salvador
2019-10-17 14:21 ` [RFC PATCH v2 01/16] mm,hwpoison: cleanup unused PageHuge() check Oscar Salvador
2019-10-18 11:48 ` Michal Hocko
2019-10-21 7:00 ` Naoya Horiguchi
2019-10-21 12:16 ` Michal Hocko
2019-11-12 12:22 ` Aneesh Kumar K.V
2019-11-13 6:02 ` Naoya Horiguchi
2019-10-17 14:21 ` Oscar Salvador [this message]
2019-10-18 11:52 ` [RFC PATCH v2 02/16] mm,madvise: call soft_offline_page() without MF_COUNT_INCREASED Michal Hocko
2019-10-21 7:02 ` Naoya Horiguchi
2019-10-21 12:20 ` Michal Hocko
2019-10-17 14:21 ` [RFC PATCH v2 03/16] mm,madvise: Refactor madvise_inject_error Oscar Salvador
2019-10-21 7:03 ` Naoya Horiguchi
2019-10-17 14:21 ` [RFC PATCH v2 04/16] mm,hwpoison-inject: don't pin for hwpoison_filter Oscar Salvador
2019-10-17 14:21 ` [RFC PATCH v2 05/16] mm,hwpoison: Un-export get_hwpoison_page and make it static Oscar Salvador
2019-10-21 7:03 ` Naoya Horiguchi
2019-10-17 14:21 ` [RFC PATCH v2 06/16] mm,hwpoison: Kill put_hwpoison_page Oscar Salvador
2019-10-21 7:04 ` Naoya Horiguchi
2019-10-17 14:21 ` [RFC PATCH v2 07/16] mm,hwpoison: remove MF_COUNT_INCREASED Oscar Salvador
2019-10-17 14:21 ` [RFC PATCH v2 08/16] mm,hwpoison: remove flag argument from soft offline functions Oscar Salvador
2019-10-17 14:21 ` [RFC PATCH v2 09/16] mm,hwpoison: Unify THP handling for hard and soft offline Oscar Salvador
2019-10-21 7:04 ` Naoya Horiguchi
2019-10-21 9:51 ` [PATCH 17/16] mm,hwpoison: introduce MF_MSG_UNSPLIT_THP Naoya Horiguchi
2019-10-22 8:00 ` Oscar Salvador
2019-10-17 14:21 ` [RFC PATCH v2 10/16] mm,hwpoison: Rework soft offline for free pages Oscar Salvador
2019-10-18 12:06 ` Michal Hocko
2019-10-21 12:58 ` Oscar Salvador
2019-10-21 15:41 ` Michal Hocko
2019-10-22 7:46 ` Oscar Salvador
2019-10-22 8:26 ` Michal Hocko
2019-10-22 8:35 ` Oscar Salvador
2019-10-22 9:22 ` Michal Hocko
2019-10-22 9:58 ` Oscar Salvador
2019-10-22 10:24 ` Michal Hocko
2019-10-22 10:33 ` Oscar Salvador
2019-10-23 2:15 ` Naoya Horiguchi
2019-10-23 2:01 ` Naoya Horiguchi
2019-10-21 7:45 ` Naoya Horiguchi
2019-10-22 8:00 ` Oscar Salvador
2019-10-17 14:21 ` [RFC PATCH v2 11/16] mm,hwpoison: Rework soft offline for in-use pages Oscar Salvador
2019-10-18 12:39 ` Michal Hocko
2019-10-21 13:48 ` Oscar Salvador
2019-10-21 14:06 ` Michal Hocko
2019-10-22 7:56 ` Oscar Salvador
2019-10-22 8:30 ` Michal Hocko
2019-10-22 9:40 ` Oscar Salvador
2019-10-17 14:21 ` [RFC PATCH v2 12/16] mm,hwpoison: Refactor soft_offline_huge_page and __soft_offline_page Oscar Salvador
2019-10-17 14:21 ` [RFC PATCH v2 13/16] mm,hwpoison: Take pages off the buddy when hard-offlining Oscar Salvador
2019-10-17 14:21 ` [RFC PATCH v2 14/16] mm,hwpoison: Return 0 if the page is already poisoned in soft-offline Oscar Salvador
2019-10-21 9:20 ` Naoya Horiguchi
2019-10-17 14:21 ` [RFC PATCH v2 15/16] mm/hwpoison-inject: Rip off duplicated checks Oscar Salvador
2019-10-21 9:40 ` David Hildenbrand
2019-10-22 7:57 ` Oscar Salvador
2019-10-17 14:21 ` [RFC PATCH v2 16/16] mm, soft-offline: convert parameter to pfn Oscar Salvador
2019-10-18 8:15 ` David Hildenbrand
2020-06-11 16:43 ` [RFC PATCH v2 00/16] Hwpoison rework {hard,soft}-offline Dmitry Yakunin
2020-06-15 6:19 ` HORIGUCHI NAOYA(堀口 直也)
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