mm, THP, swap: don't allocate huge cluster for file backed swap device
It's hard to write a whole transparent huge page (THP) to a file backed
swap device during swapping out and the file backed swap device isn't
very popular. So the huge cluster allocation for the file backed swap
device is disabled.
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: "Huang, Ying" <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Minchan Kim <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Shaohua Li <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: "Kirill A . Shutemov" <[email protected]>
Cc: Andrea Arcangeli <[email protected]>
Cc: Dan Williams <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Ross Zwisler <[email protected]> [for brd.c, zram_drv.c, pmem.c]
Cc: Vishal L Verma <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 2bfbfb87..267b1fe 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -948,9 +948,10 @@ int get_swap_pages(int n_goal, bool cluster, swp_entry_t swp_entries[])
spin_unlock(&si->lock);
goto nextsi;
}
- if (cluster)
- n_ret = swap_alloc_cluster(si, swp_entries);
- else
+ if (cluster) {
+ if (!(si->flags & SWP_FILE))
+ n_ret = swap_alloc_cluster(si, swp_entries);
+ } else
n_ret = scan_swap_map_slots(si, SWAP_HAS_CACHE,
n_goal, swp_entries);
spin_unlock(&si->lock);
