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 Signed-off-by: Wu Fengguang --- fs/btrfs/file.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- linux-next.orig/fs/btrfs/file.c 2011-08-29 19:14:32.000000000 +0800 +++ linux-next/fs/btrfs/file.c 2011-08-29 19:14:40.000000000 +0800 @@ -1138,7 +1138,8 @@ again: 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])); } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/