]> git.proxmox.com Git - mirror_ubuntu-kernels.git/commit
ext4: avoid unnecessary spreading of allocations among groups
authorJan Kara <jack@suse.cz>
Thu, 8 Sep 2022 09:21:25 +0000 (11:21 +0200)
committerTheodore Ts'o <tytso@mit.edu>
Thu, 22 Sep 2022 02:11:41 +0000 (22:11 -0400)
commit1940265ede6683f6317cba0d428ce6505eaca944
tree43e1af0622798403d3602f11b9777612866d5178
parent4fca50d440cc5d4dc570ad5484cc0b70b381bc2a
ext4: avoid unnecessary spreading of allocations among groups

mb_set_largest_free_order() updates lists containing groups with largest
chunk of free space of given order. The way it updates it leads to
always moving the group to the tail of the list. Thus allocations
looking for free space of given order effectively end up cycling through
all groups (and due to initialization in last to first order). This
spreads allocations among block groups which reduces performance for
rotating disks or low-end flash media. Change
mb_set_largest_free_order() to only update lists if the order of the
largest free chunk in the group changed.

Fixes: 196e402adf2e ("ext4: improve cr 0 / cr 1 group scanning")
CC: stable@kernel.org
Reported-and-tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Tested-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/all/0d81a7c2-46b7-6010-62a4-3e6cfc1628d6@i2se.com/
Link: https://lore.kernel.org/r/20220908092136.11770-2-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
fs/ext4/mballoc.c