From: Huang Ying <ying.huang@xxxxxxxxx> Subject: 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/20170724051840.2309-5-ying.huang@xxxxxxxxx Signed-off-by: "Huang, Ying" <ying.huang@xxxxxxxxx> Cc: Johannes Weiner <hannes@xxxxxxxxxxx> Cc: Minchan Kim <minchan@xxxxxxxxxx> Cc: Hugh Dickins <hughd@xxxxxxxxxx> Cc: Shaohua Li <shli@xxxxxxxxxx> Cc: Rik van Riel <riel@xxxxxxxxxx> Cc: "Kirill A . Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx> Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx> Cc: Dan Williams <dan.j.williams@xxxxxxxxx> Cc: Jens Axboe <axboe@xxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxxxx> Cc: Ross Zwisler <ross.zwisler@xxxxxxxxx> [for brd.c, zram_drv.c, pmem.c] Cc: Vishal L Verma <vishal.l.verma@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/swapfile.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff -puN mm/swapfile.c~mm-thp-swap-dont-allocate-huge-cluster-for-file-backed-swap-device mm/swapfile.c --- a/mm/swapfile.c~mm-thp-swap-dont-allocate-huge-cluster-for-file-backed-swap-device +++ a/mm/swapfile.c @@ -948,9 +948,10 @@ start_over: 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); _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
