Commit 8cef107a authored Mar 15, 2010 by Frans van de Wiel Committed by Jan Kara May 21, 2010

ext3: Avoid loading bitmaps for full groups during block allocation

There is no point in loading bitmap for groups which are completely full.
This causes noticeable performance problems (and memory pressure) on small
systems with large full filesystem
(http://marc.info/?l=linux-ext4&m=126843108314310&w=2

).

Jan Kara: Added a comment and changed check to use cpu-endian value.

Signed-off-by: "Frans van de Wiel" <fvdw@fvdw.eu>
Signed-off-by: Jan Kara <jack@suse.cz>

parent 70ca0a42

fs/ext3/balloc.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -1583,6 +1583,12 @@ ext3_fsblk_t ext3_new_blocks(handle_t handle, struct inode inode,
		if (!gdp)
		goto io_error;
		free_blocks = le16_to_cpu(gdp->bg_free_blocks_count);
		/*
		* skip this group (and avoid loading bitmap) if there
		* are no free blocks
		*/
		if (!free_blocks)
		continue;
		/*
		* skip this group if the number of
		* free blocks is less than half of the reservation