From: Miklos Szeredi <[email protected]>
The function do_lo_send_aops() should call
balance_dirty_pages_ratelimited() after each page similarly to
generic_file_buffered_write().
Without this, writing the loop device directly (not through a
filesystem) is very slow, and also slows the whole system down,
because nr_dirty is constantly over the limit.
Beware: this patch without the fix to balance_dirty_pages() makes a
loopback mounted filesystem prone to deadlock.
Signed-off-by: Miklos Szeredi <[email protected]>
---
Index: linux/drivers/block/loop.c
===================================================================
--- linux.orig/drivers/block/loop.c 2007-02-27 14:40:55.000000000 +0100
+++ linux/drivers/block/loop.c 2007-02-27 14:41:08.000000000 +0100
@@ -275,6 +275,8 @@ static int do_lo_send_aops(struct loop_d
pos += size;
unlock_page(page);
page_cache_release(page);
+ balance_dirty_pages_ratelimited(mapping);
+ cond_resched();
}
ret = 0;
out:
--