From: Aditya Kali <adityakali@google.com>
Date: Sat, 30 Jun 2012 23:10:57 +0000 (-0400)
Subject: ext4: avoid uneeded calls to ext4_mb_load_buddy() while reading mb_groups
X-Git-Tag: v3.6-rc1~69^2~22
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1c8457cadc9cefe7ec920a2f3537ff1fe20f4061;p=pandora-kernel.git

ext4: avoid uneeded calls to ext4_mb_load_buddy() while reading mb_groups

Currently ext4_mb_load_buddy is called for every group, irrespective
of whether the group info is already in memory, while reading
/proc/fs/ext4/<partition>/mb_groups proc file.  For the purpose of
mb_groups proc file, it is unnecessary to load the file group info
from disk if it was loaded in past.  These calls to ext4_mb_load_buddy
make reading the mb_groups proc file expensive.

Also, the locks around ext4_get_group_info are not required.

This patch modifies the code to call ext4_mb_load_buddy only if the
group info had never been loaded into memory in past. It also removes
the mb group locking around ext4_get_group_info call.

Signed-off-by: Aditya Kali <adityakali@google.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
---

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