The patch titled
Subject: mm: fix bogus VM_BUG_ON_PAGE() in isolate_lru_page()
has been added to the -mm tree. Its filename is
mm-fix-bogus-vm_bug_on_page-in-isolate_lru_page.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-fix-bogus-vm_bug_on_page-in-isolate_lru_page.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-fix-bogus-vm_bug_on_page-in-isolate_lru_page.patch
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------------------------------------------------------
From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Subject: mm: fix bogus VM_BUG_ON_PAGE() in isolate_lru_page()
We don't care if there's a tail pages which is not on LRU. We are not
going to isolate them anyway.
Testcase:
#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
#include <sys/mman.h>
#include <numaif.h>
#define SIZE 0x2000
int foo;
int main()
{
int fd;
char *p;
unsigned long mask = 2;
fd = open("/dev/sg0", O_RDWR);
p = mmap(NULL, SIZE, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
/* Faultin pages */
foo = p[0] + p[0x1000];
mbind(p, SIZE, MPOL_BIND, &mask, 4, MPOL_MF_MOVE | MPOL_MF_STRICT);
return 0;
}
MPOL_MF_STRICT makes queue_pages_test_walk() ignore !vma_megratable()
and we try to queue such pages for migration. It's good question why we
ignore !vma_megratable() for MPOL_MF_STRICT, but it's subject for a
separate patch.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Fixes: bb5b8589767a ("mm: make sure isolate_lru_page() is never called for tail page"
Reported-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/vmscan.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff -puN mm/vmscan.c~mm-fix-bogus-vm_bug_on_page-in-isolate_lru_page mm/vmscan.c
--- a/mm/vmscan.c~mm-fix-bogus-vm_bug_on_page-in-isolate_lru_page
+++ a/mm/vmscan.c
@@ -1443,7 +1443,7 @@ int isolate_lru_page(struct page *page)
int ret = -EBUSY;
VM_BUG_ON_PAGE(!page_count(page), page);
- VM_BUG_ON_PAGE(PageTail(page), page);
+ VM_BUG_ON_PAGE(PageLRU(page) && PageTail(page), page);
if (PageLRU(page)) {
struct zone *zone = page_zone(page);
_
Patches currently in -mm which might be from kirill.shutemov@xxxxxxxxxxxxxxx are
thp-make-split_queue-per-node.patch
thp-change-deferred_split_count-to-return-number-of-thp-in-queue.patch
thp-change-deferred_split_count-to-return-number-of-thp-in-queue-fix.patch
thp-limit-number-of-object-to-scan-on-deferred_split_scan.patch
drivers-scsi-sgc-mark-vma-as-vm_io-to-prevent-migration.patch
mm-fix-bogus-vm_bug_on_page-in-isolate_lru_page.patch
mempolicy-do-not-try-to-queue-pages-from-vma_migratable.patch
mm-make-swapin-readahead-to-improve-thp-collapse-rate-fix.patch
mm-make-swapin-readahead-to-improve-thp-collapse-rate-fix-2.patch
mm-make-swapin-readahead-to-improve-thp-collapse-rate-fix-3.patch
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