From 2ed5724d5a78a22864ef0bd6af4fcb8a15379f00 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Wed, 12 Jun 2013 11:43:02 -0400 Subject: [PATCH] ext4: add cond_resched() to ext4_free_blocks() & ext4_mb_regular_allocator() For a file systems with a very large number of block groups, if all of the block group bitmaps are in memory and the file system is relatively badly fragmented, it's possible ext4_mb_regular_allocator() to take a long time trying to find a good match. This is especially true if the tuning parameter mb_max_to_scan has been sent to a very large number. So add a cond_resched() to avoid soft lockup warnings and to provide better system responsiveness. For ext4_free_blocks(), if we are deleting a large range of blocks, and data=journal is enabled so that EXT4_FREE_BLOCKS_FORGET is passed, the loop to call sb_find_get_block() and to call ext4_forget() can take over 10-15 milliseocnds or more. So it's better to add a cond_resched() here a well. Signed-off-by: "Theodore Ts'o" --- fs/ext4/mballoc.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index def84082a9a9..1a9c22b45a01 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -2105,6 +2105,7 @@ repeat: group = ac->ac_g_ex.fe_group; for (i = 0; i < ngroups; group++, i++) { + cond_resched(); /* * Artificially restricted ngroups for non-extent * files makes group > ngroups possible on first loop. @@ -4612,10 +4613,11 @@ void ext4_free_blocks(handle_t *handle, struct inode *inode, BUG_ON(bh && (count > 1)); for (i = 0; i < count; i++) { + cond_resched(); if (!bh) tbh = sb_find_get_block(inode->i_sb, block + i); - if (unlikely(!tbh)) + if (!tbh) continue; ext4_forget(handle, flags & EXT4_FREE_BLOCKS_METADATA, inode, tbh, block + i); -- 2.20.1