Bug 707755

Summary:	blkio controller: Backport patches for per cgroup stats and lockless throttling for no rule group
Product:	Red Hat Enterprise Linux 6	Reporter:	Vivek Goyal <vgoyal>
Component:	kernel	Assignee:	Vivek Goyal <vgoyal>
Status:	CLOSED ERRATA	QA Contact:	Mike Gahagan <mgahagan>
Severity:	medium	Docs Contact:
Priority:	medium
Version:	6.2	CC:	arozansk, juzhang, kzhang
Target Milestone:	rc
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	kernel-2.6.32-160.el6	Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2011-12-06 13:08:05 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:

Description Vivek Goyal 2011-05-25 20:38:12 UTC

Description of problem:

IO controller has IO throttling policy. That throttling policy takes request queue
lock for every bio even if there are no throttling rules in the group. Request queue lock is already heavily contended. This patch series avoids taking that lock when there are no rules in the group.

This is a common scenario for majority of customers where there are no rules in root group while IO is happening. Avoid taking request queue lock for such cases.

This series also makes some of the stats per cpu so that we avoid taking
blkg->stats_lock.

Version-Release number of selected component (if applicable):


How reproducible:


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Comment 3 RHEL Program Management 2011-06-03 20:00:32 UTC

This request was evaluated by Red Hat Product Management for inclusion
in a Red Hat Enterprise Linux maintenance release. Product Management has 
requested further review of this request by Red Hat Engineering, for potential
inclusion in a Red Hat Enterprise Linux Update release for currently deployed 
products. This request is not yet committed for inclusion in an Update release.

Comment 4 Aristeu Rozanski 2011-06-27 19:03:49 UTC

Patch(es) available on kernel-2.6.32-160.el6

Comment 7 Mike Gahagan 2011-11-01 17:38:56 UTC

Confirmed blkio stats described in the patches are present and blkio controller is functional using both ltp tests as well as throttling I/O in a guest system on a RHEL 6.2 host.

Comment 8 errata-xmlrpc 2011-12-06 13:08:05 UTC

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

http://rhn.redhat.com/errata/RHSA-2011-1530.html