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authorHuang Ying <ying.huang@intel.com>2017-09-06 16:22:34 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-09-06 17:27:28 -0700
commit59807685a7e77e8c8fe5925613968841538d53d7 (patch)
treec2827c8a22e600f36258d6137a131a7150577b72 /include/linux/swap.h
parent225311a46411c37e20e73d99f4382f141e12f6f9 (diff)
mm, THP, swap: support splitting THP for THP swap out
After adding swapping out support for THP (Transparent Huge Page), it is possible that a THP in swap cache (partly swapped out) need to be split. To split such a THP, the swap cluster backing the THP need to be split too, that is, the CLUSTER_FLAG_HUGE flag need to be cleared for the swap cluster. The patch implemented this. And because the THP swap writing needs the THP keeps as huge page during writing. The PageWriteback flag is checked before splitting. Link: http://lkml.kernel.org/r/20170724051840.2309-8-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 'include/linux/swap.h')
-rw-r--r--include/linux/swap.h9
1 files changed, 9 insertions, 0 deletions
diff --git a/include/linux/swap.h b/include/linux/swap.h
index 7176ba780e83..461cf107ad52 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -527,6 +527,15 @@ static inline swp_entry_t get_swap_page(struct page *page)
#endif /* CONFIG_SWAP */
+#ifdef CONFIG_THP_SWAP
+extern int split_swap_cluster(swp_entry_t entry);
+#else
+static inline int split_swap_cluster(swp_entry_t entry)
+{
+ return 0;
+}
+#endif
+
#ifdef CONFIG_MEMCG
static inline int mem_cgroup_swappiness(struct mem_cgroup *memcg)
{