Bug 215939

Summary:	kernel dm: use private biosets to avoid deadlock under memory pressure
Product:	Red Hat Enterprise Linux 4	Reporter:	Milan Broz <mbroz>
Component:	kernel	Assignee:	Milan Broz <mbroz>
Status:	CLOSED ERRATA	QA Contact:	Brian Brock <bbrock>
Severity:	medium	Docs Contact:
Priority:	medium
Version:	4.4	CC:	agk, christophe.varoqui, coughlan, dwysocha, dzickus, egoggin, jbaron, jbrassow, junichi.nomura, kueda, lmb, mbroz, pvrabec, tranlan
Target Milestone:	---
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	RHBA-2007-0304	Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2007-05-08 04:08:10 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description Milan Broz 2006-11-16 13:42:15 UTC

+++ This bug was initially created as a clone of Bug #209851 +++
RHEL4.5 clone

To avoid deadlock under memory pressure it is necessary for dm layers to use
private mempools and not share them.

Comment 1 RHEL Program Management 2006-11-16 13:45:31 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 3 Tom Coughlan 2006-12-08 22:46:25 UTC

Milan,

Can you add some information about how common this problem is? Has it been seen
in the field? Typical workloads and configurations? Or strictly theoretical or
unrealistic configs?  

Tom

Comment 4 Milan Broz 2006-12-08 23:17:13 UTC

This problem can only happen in low memory situations when higher level (fs or
upper stacked dm device) succesfully allocate bios but lower level does not
because of low memory (upper levels drain common memory pool).

I saw this problem upstream but actually have no reports in RHEL4 but it use
similar code...

There are no biosets in RHEL4 kernel so implementation will require backporting
of changes in block layer.

Comment 10 RHEL Program Management 2006-12-14 13:31:17 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 12 Jay Turner 2007-01-02 13:47:31 UTC

QE ack for RHEL4.5.

Comment 13 Jason Baron 2007-01-02 18:52:07 UTC

committed in stream U5 build 42.36. A test kernel with this patch is available
from http://people.redhat.com/~jbaron/rhel4/

Comment 16 Red Hat Bugzilla 2007-05-08 04:08:10 UTC

An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on the solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.

http://rhn.redhat.com/errata/RHBA-2007-0304.html