btrfs: fix dirtied pages accounting on sub-page writes

When doing 1KB sequential writes to the same page,
balance_dirty_pages_ratelimited_nr() should be called once instead of 4
times, the latter makes the dirtier tasks be throttled much too heavy.

Fix it with proper de-accounting on clear_page_dirty_for_io().

CC: Chris Mason <chris.mason@oracle.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
This commit is contained in:
Wu Fengguang 2011-08-08 15:19:47 -06:00
parent 2f800fbd77
commit 32c7f202a4

View file

@ -1136,7 +1136,8 @@ static noinline int prepare_pages(struct btrfs_root *root, struct file *file,
GFP_NOFS);
}
for (i = 0; i < num_pages; i++) {
clear_page_dirty_for_io(pages[i]);
if (clear_page_dirty_for_io(pages[i]))
account_page_redirty(pages[i]);
set_page_extent_mapped(pages[i]);
WARN_ON(!PageLocked(pages[i]));
}