The patch titled
Subject: mm/khugepaged: fix the xas_create_range() error path
has been added to the -mm tree. Its filename is
mm-khugepaged-fix-the-xas_create_range-error-path.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-khugepaged-fix-the-xas_create_range-error-path.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-khugepaged-fix-the-xas_create_range-error-path.patch
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------------------------------------------------------
From: Hugh Dickins <hughd@xxxxxxxxxx>
Subject: mm/khugepaged: fix the xas_create_range() error path
collapse_shmem()'s xas_nomem() is very unlikely to fail, but it is rightly
given a failure path, so move the whole xas_create_range() block up before
__SetPageLocked(new_page): so that it does not need to remember to
unlock_page(new_page). Add the missing mem_cgroup_cancel_charge(), and
set (currently unused) result to SCAN_FAIL rather than SCAN_SUCCEED.
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.1811261531200.2275@eggly.anvils
Fixes: 77da9389b9d5 ("mm: Convert collapse_shmem to XArray")
Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Jerome Glisse <jglisse@xxxxxxxxxx>
Cc: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
--- a/mm/khugepaged.c~mm-khugepaged-fix-the-xas_create_range-error-path
+++ a/mm/khugepaged.c
@@ -1329,6 +1329,20 @@ static void collapse_shmem(struct mm_str
goto out;
}
+ /* This will be less messy when we use multi-index entries */
+ do {
+ xas_lock_irq(&xas);
+ xas_create_range(&xas);
+ if (!xas_error(&xas))
+ break;
+ xas_unlock_irq(&xas);
+ if (!xas_nomem(&xas, GFP_KERNEL)) {
+ mem_cgroup_cancel_charge(new_page, memcg, true);
+ result = SCAN_FAIL;
+ goto out;
+ }
+ } while (1);
+
__SetPageLocked(new_page);
__SetPageSwapBacked(new_page);
new_page->index = start;
@@ -1340,17 +1354,6 @@ static void collapse_shmem(struct mm_str
* be able to map it or use it in another way until we unlock it.
*/
- /* This will be less messy when we use multi-index entries */
- do {
- xas_lock_irq(&xas);
- xas_create_range(&xas);
- if (!xas_error(&xas))
- break;
- xas_unlock_irq(&xas);
- if (!xas_nomem(&xas, GFP_KERNEL))
- goto out;
- } while (1);
-
xas_set(&xas, start);
for (index = start; index < end; index++) {
struct page *page = xas_next(&xas);
_
Patches currently in -mm which might be from hughd@xxxxxxxxxx are
mm-huge_memory-rename-freeze_page-to-unmap_page.patch
mm-huge_memory-splitting-set-mappingindex-before-unfreeze.patch
mm-huge_memory-fix-lockdep-complaint-on-32-bit-i_size_read.patch
mm-khugepaged-collapse_shmem-stop-if-punched-or-truncated.patch
mm-khugepaged-fix-crashes-due-to-misaccounted-holes.patch
mm-khugepaged-collapse_shmem-remember-to-clear-holes.patch
mm-khugepaged-minor-reorderings-in-collapse_shmem.patch
mm-khugepaged-collapse_shmem-without-freezing-new_page.patch
mm-khugepaged-collapse_shmem-do-not-crash-on-compound.patch
mm-khugepaged-fix-the-xas_create_range-error-path.patch
mm-put_and_wait_on_page_locked-while-page-is-migrated.patch
