The function generic_swapfile_activate can take quite long time, it iterates over all blocks of a file, so add cond_resched to it. I observed about 1 second stalls when activating a swapfile that was almost unfragmented - this patch fixes it. Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx> --- mm/page_io.c | 2 ++ 1 file changed, 2 insertions(+) Index: linux-4.7-rc7/mm/page_io.c =================================================================== --- linux-4.7-rc7.orig/mm/page_io.c 2016-05-30 17:34:37.000000000 +0200 +++ linux-4.7-rc7/mm/page_io.c 2016-07-11 17:23:33.000000000 +0200 @@ -166,6 +166,8 @@ int generic_swapfile_activate(struct swa unsigned block_in_page; sector_t first_block; + cond_resched(); + first_block = bmap(inode, probe_block); if (first_block == 0) goto bad_bmap; -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>