From: Chris Mason <chris.mason@oracle.com>
Date: Wed, 25 Jun 2008 20:14:04 +0000 (-0400)
Subject: Btrfs: Reduce contention on the root node
X-Git-Tag: v2.6.29-rc1~27^2~9^2~55^2~56^2~30^2~131
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f9efa9c784aa3b801feb367f72c6867d26fb348e;p=pandora-kernel.git

Btrfs: Reduce contention on the root node

This calls unlock_up sooner in btrfs_search_slot in order to decrease the
amount of work done with the higher level tree locks held.

Also, it changes btrfs_tree_lock to spin for a big against the page lock
before scheduling.  This makes a big difference in context switch rate under
highly contended workloads.

Longer term, a better locking structure is needed than the page lock.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
---

Reading git-diff-tree failed