* [PATCH v1 1/2] mm: hwpoison: call shake_page() unconditionally
2017-04-26 9:10 [PATCH v1 0/2] mm: hwpoison: fix mce-test.ras.fail on 23a003bfd2 Naoya Horiguchi
@ 2017-04-26 9:10 ` Naoya Horiguchi
2017-04-26 9:10 ` [PATCH v1 2/2] mm: hwpoison: call shake_page() after try_to_unmap() for mlocked page Naoya Horiguchi
1 sibling, 0 replies; 3+ messages in thread
From: Naoya Horiguchi @ 2017-04-26 9:10 UTC (permalink / raw)
To: linux-mm
Cc: xiaolong.ye, Andrew Morton, Chen Gong, lkp, linux-kernel,
Naoya Horiguchi, Naoya Horiguchi
shake_page() is called before going into core error handling code in order
to ensure that the error page is flushed from lru_cache lists where pages
stay during transferring among LRU lists.
But currently it's not fully functional because when the page is linked to
lru_cache by calling activate_page(), its PageLRU flag is set and
shake_page() is skipped. The result is to fail error handling with "still
referenced by 1 users" message.
When the page is linked to lru_cache by isolate_lru_page(), its PageLRU is
clear, so that's fine.
This patch makes shake_page() unconditionally called to avoild the failure.
Link: http://lkml.kernel.org/r/20170417055948.GM31394@yexl-desktop
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
---
mm/hwpoison-inject.c | 3 +--
mm/memory-failure.c | 27 +++++++++++----------------
2 files changed, 12 insertions(+), 18 deletions(-)
diff --git v4.11-rc6-mmotm-2017-04-13-14-50/mm/hwpoison-inject.c v4.11-rc6-mmotm-2017-04-13-14-50_patched/mm/hwpoison-inject.c
index 9d26fd9..356df05 100644
--- v4.11-rc6-mmotm-2017-04-13-14-50/mm/hwpoison-inject.c
+++ v4.11-rc6-mmotm-2017-04-13-14-50_patched/mm/hwpoison-inject.c
@@ -34,8 +34,7 @@ static int hwpoison_inject(void *data, u64 val)
if (!hwpoison_filter_enable)
goto inject;
- if (!PageLRU(hpage) && !PageHuge(p))
- shake_page(hpage, 0);
+ shake_page(hpage, 0);
/*
* This implies unable to support non-LRU pages.
*/
diff --git v4.11-rc6-mmotm-2017-04-13-14-50/mm/memory-failure.c v4.11-rc6-mmotm-2017-04-13-14-50_patched/mm/memory-failure.c
index 8c02811..77cf9c3 100644
--- v4.11-rc6-mmotm-2017-04-13-14-50/mm/memory-failure.c
+++ v4.11-rc6-mmotm-2017-04-13-14-50_patched/mm/memory-failure.c
@@ -220,6 +220,9 @@ static int kill_proc(struct task_struct *t, unsigned long addr, int trapno,
*/
void shake_page(struct page *p, int access)
{
+ if (PageHuge(p))
+ return;
+
if (!PageSlab(p)) {
lru_add_drain_all();
if (PageLRU(p))
@@ -1140,22 +1143,14 @@ int memory_failure(unsigned long pfn, int trapno, int flags)
* The check (unnecessarily) ignores LRU pages being isolated and
* walked by the page reclaim code, however that's not a big loss.
*/
- if (!PageHuge(p)) {
- if (!PageLRU(p))
- shake_page(p, 0);
- if (!PageLRU(p)) {
- /*
- * shake_page could have turned it free.
- */
- if (is_free_buddy_page(p)) {
- if (flags & MF_COUNT_INCREASED)
- action_result(pfn, MF_MSG_BUDDY, MF_DELAYED);
- else
- action_result(pfn, MF_MSG_BUDDY_2ND,
- MF_DELAYED);
- return 0;
- }
- }
+ shake_page(p, 0);
+ /* shake_page could have turned it free. */
+ if (!PageLRU(p) && is_free_buddy_page(p)) {
+ if (flags & MF_COUNT_INCREASED)
+ action_result(pfn, MF_MSG_BUDDY, MF_DELAYED);
+ else
+ action_result(pfn, MF_MSG_BUDDY_2ND, MF_DELAYED);
+ return 0;
}
lock_page(hpage);
--
2.7.0
--
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^ permalink raw reply [flat|nested] 3+ messages in thread* [PATCH v1 2/2] mm: hwpoison: call shake_page() after try_to_unmap() for mlocked page
2017-04-26 9:10 [PATCH v1 0/2] mm: hwpoison: fix mce-test.ras.fail on 23a003bfd2 Naoya Horiguchi
2017-04-26 9:10 ` [PATCH v1 1/2] mm: hwpoison: call shake_page() unconditionally Naoya Horiguchi
@ 2017-04-26 9:10 ` Naoya Horiguchi
1 sibling, 0 replies; 3+ messages in thread
From: Naoya Horiguchi @ 2017-04-26 9:10 UTC (permalink / raw)
To: linux-mm
Cc: xiaolong.ye, Andrew Morton, Chen Gong, lkp, linux-kernel,
Naoya Horiguchi, Naoya Horiguchi
Memory error handler calls try_to_unmap() for error pages in various
states. If the error page is a mlocked page, error handling could fail
with "still referenced by 1 users" message. This is because the page
is linked to and stays in lru cache after the following call chain.
try_to_unmap_one
page_remove_rmap
clear_page_mlock
putback_lru_page
lru_cache_add
memory_failure() calls shake_page() to hanlde the similar issue, but
current code doesn't cover because shake_page() is called only before
try_to_unmap(). So this patches adds shake_page().
Link: http://lkml.kernel.org/r/20170417055948.GM31394@yexl-desktop
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
---
mm/memory-failure.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git v4.11-rc6-mmotm-2017-04-13-14-50/mm/memory-failure.c v4.11-rc6-mmotm-2017-04-13-14-50_patched/mm/memory-failure.c
index 77cf9c3..57f07ec 100644
--- v4.11-rc6-mmotm-2017-04-13-14-50/mm/memory-failure.c
+++ v4.11-rc6-mmotm-2017-04-13-14-50_patched/mm/memory-failure.c
@@ -919,6 +919,7 @@ static bool hwpoison_user_mappings(struct page *p, unsigned long pfn,
bool unmap_success;
int kill = 1, forcekill;
struct page *hpage = *hpagep;
+ bool mlocked = PageMlocked(hpage);
/*
* Here we are interested only in user-mapped pages, so skip any
@@ -983,6 +984,13 @@ static bool hwpoison_user_mappings(struct page *p, unsigned long pfn,
pfn, page_mapcount(hpage));
/*
+ * try_to_unmap() might put mlocked page in lru cache, so call
+ * shake_page() again to ensure that it's flushed.
+ */
+ if (mlocked)
+ shake_page(hpage, 0);
+
+ /*
* Now that the dirty bit has been propagated to the
* struct page and all unmaps done we can decide if
* killing is needed or not. Only kill when the page
--
2.7.0
--
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^ permalink raw reply [flat|nested] 3+ messages in thread