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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 /mm
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 'mm')
-rw-r--r--mm/huge_memory.c10
-rw-r--r--mm/swapfile.c15
2 files changed, 24 insertions, 1 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 02dfe635c9fe..772048c233d1 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2481,6 +2481,9 @@ int split_huge_page_to_list(struct page *page, struct list_head *list)
VM_BUG_ON_PAGE(!PageLocked(page), page);
VM_BUG_ON_PAGE(!PageCompound(page), page);
+ if (PageWriteback(page))
+ return -EBUSY;
+
if (PageAnon(head)) {
/*
* The caller does not necessarily hold an mmap_sem that would
@@ -2558,7 +2561,12 @@ int split_huge_page_to_list(struct page *page, struct list_head *list)
__dec_node_page_state(page, NR_SHMEM_THPS);
spin_unlock(&pgdata->split_queue_lock);
__split_huge_page(page, list, flags);
- ret = 0;
+ if (PageSwapCache(head)) {
+ swp_entry_t entry = { .val = page_private(head) };
+
+ ret = split_swap_cluster(entry);
+ } else
+ ret = 0;
} else {
if (IS_ENABLED(CONFIG_DEBUG_VM) && mapcount) {
pr_alert("total_mapcount: %u, page_count(): %u\n",
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 267b1fe41844..42eff9e4e972 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1216,6 +1216,21 @@ static void swapcache_free_cluster(swp_entry_t entry)
}
}
}
+
+int split_swap_cluster(swp_entry_t entry)
+{
+ struct swap_info_struct *si;
+ struct swap_cluster_info *ci;
+ unsigned long offset = swp_offset(entry);
+
+ si = _swap_info_get(entry);
+ if (!si)
+ return -EBUSY;
+ ci = lock_cluster(si, offset);
+ cluster_clear_huge(ci);
+ unlock_cluster(ci);
+ return 0;
+}
#else
static inline void swapcache_free_cluster(swp_entry_t entry)
{