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authorHuang Ying <ying.huang@intel.com>2017-09-06 16:22:19 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-09-06 17:27:27 -0700
commitba3c4ce6def4915093be80585ff69f780630f32f (patch)
tree3fa890d652981cc54c5ebd7ea59cfc134fad4a6c /mm/memory.c
parente07098294adfd03d582af7626752255e3d170393 (diff)
downloadlinux-ba3c4ce6def4915093be80585ff69f780630f32f.tar.bz2
mm, THP, swap: make reuse_swap_page() works for THP swapped out
After supporting to delay THP (Transparent Huge Page) splitting after swapped out, it is possible that some page table mappings of the THP are turned into swap entries. So reuse_swap_page() need to check the swap count in addition to the map count as before. This patch done that. In the huge PMD write protect fault handler, in addition to the page map count, the swap count need to be checked too, so the page lock need to be acquired too when calling reuse_swap_page() in addition to the page table lock. [ying.huang@intel.com: silence a compiler warning] Link: http://lkml.kernel.org/r/87bmnzizjy.fsf@yhuang-dev.intel.com Link: http://lkml.kernel.org/r/20170724051840.2309-4-ying.huang@intel.com Signed-off-by: "Huang, Ying" <ying.huang@intel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: Shaohua Li <shli@kernel.org> Cc: Rik van Riel <riel@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Michal Hocko <mhocko@kernel.org> Cc: Ross Zwisler <ross.zwisler@intel.com> [for brd.c, zram_drv.c, pmem.c] Cc: Vishal L Verma <vishal.l.verma@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memory.c')
-rw-r--r--mm/memory.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/mm/memory.c b/mm/memory.c
index 1416485e278c..3dd8bb46391b 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2619,7 +2619,7 @@ static int do_wp_page(struct vm_fault *vmf)
* not dirty accountable.
*/
if (PageAnon(vmf->page) && !PageKsm(vmf->page)) {
- int total_mapcount;
+ int total_map_swapcount;
if (!trylock_page(vmf->page)) {
get_page(vmf->page);
pte_unmap_unlock(vmf->pte, vmf->ptl);
@@ -2634,8 +2634,8 @@ static int do_wp_page(struct vm_fault *vmf)
}
put_page(vmf->page);
}
- if (reuse_swap_page(vmf->page, &total_mapcount)) {
- if (total_mapcount == 1) {
+ if (reuse_swap_page(vmf->page, &total_map_swapcount)) {
+ if (total_map_swapcount == 1) {
/*
* The page is all ours. Move it to
* our anon_vma so the rmap code will