tree d3f479c1431a2607d7154d7a1e10878533d38008
parent 3a01aa7a25274308fe813a6237f678aed901cea3
author Chris Mason <chris.mason@fusionio.com> 1362435211 -0500
committer Chris Mason <chris.mason@fusionio.com> 1362660760 -0500

Btrfs: improve the delayed inode throttling

The delayed inode code batches up changes to the btree in hopes of doing
them in bulk.  As the changes build up, processes kick off worker
threads and wait for them to make progress.

The current code kicks off an async work queue item for each delayed
node, which creates a lot of churn.  It also uses a fixed 1 HZ waiting
period for the throttle, which allows us to build a lot of pending
work and can slow down the commit.

This changes us to watch a sequence counter as it is bumped during the
operations.  We kick off fewer work items and have each work item do
more work.

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