Bug 672937 – backport set_iounmap_nonlazy() to speedup reading of /proc/vmcore

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Bug 672937 - backport set_iounmap_nonlazy() to speedup reading of /proc/vmcore

Summary:	backport set_iounmap_nonlazy() to speedup reading of /proc/vmcore

Status:	CLOSED ERRATA

Aliases:	None

Product:	Red Hat Enterprise Linux 6
Classification:	Red Hat
Component:	kernel (Show other bugs)
Sub Component:
Version:	6.1
Hardware:	Unspecified Unspecified

Priority	urgent Severity urgent
Target Milestone:	rc
Target Release:	---
Assigned To:	Neil Horman
QA Contact:	chen yuwen
Docs Contact:

URL:
Whiteboard:
Keywords:	ZStream

Depends On:
Blocks:	683442
	Show dependency tree / graph

Reported:	2011-01-26 13:28 EST by Dave Maley
Modified:	2011-05-19 08:50 EDT (History)
CC List:	7 users (show)

See Also:
Fixed In Version:	kernel-2.6.32-121.el6
Doc Type:	Bug Fix
Doc Text:	Reading the /proc/vmcore file was previously significantly slower on a Red Hat Enterprise Linux 6 system when compared to a Red Hat Enterprise Linux 5 system. This update enables caching of memory accesses; reading of the /proc/vmcore file is now noticeably faster.
Story Points:	---
Clone Of:
Environment:
Last Closed:	2011-05-19 08:50:00 EDT
Type:	---
Regression:	---
Mount Type:	---
Documentation:	---
CRM:
Verified Versions:
Category:	---
oVirt Team:	---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---

Attachments	(Terms of Use)
backport of commit 3ee48b6af49cf534ca2f481ecc484b156a41451d (1.67 KB, patch) 2011-01-26 14:30 EST, Dave Maley	no flags	Details \| Diff
Add an attachment (proposed patch, testcase, etc.)

External Trackers
Tracker	ID	Priority	Status	Summary	Last Updated
Red Hat Product Errata	RHSA-2011:0542	normal	SHIPPED_LIVE	Important: Red Hat Enterprise Linux 6.1 kernel security, bug fix and enhancement update	2011-05-19 07:58:07 EDT

Groups: None (edit)

Description Dave Maley 2011-01-26 13:28:38 EST

Description of problem:
Reading /proc/vmcore is significantly slower on RHEL6 compared to RHEL5.  The patch from bug 641315 helps to improve things however another patch has been committed upstream which further helps boost performance closer to that of RHEL5.

http://git.kernel.org/?p=linux/kernel/git/x86/linux-2.6-tip.git;a=commitdiff;h=3ee48b6af49cf534ca2f481ecc484b156a41451d


Version-Release number of selected component (if applicable):
kernel-2.6.32-71.e16
kernel-2.6.32-89.el6 (includes patch from bug 641315)


How reproducible:
Always


Steps to Reproduce:
1. configure kdump
2. crash system
3. time duration


Actual results:
A RHEL6 system w/ 8GB ram takes 4 minutes 16 seconds.  On the same system RHEL5.5 is less than 20 seconds.  The patch from bug 641315 improves it to 2 minutes 32 seconds.


Expected results:
Performance similar to RHEL5.5.


Additional info:
Business impact: This issue will cause huge increase in service down time on a server with large memory on RHEL6.

Comment 1 Dave Maley 2011-01-26 14:30:38 EST

Created attachment 475470 [details]
backport of commit 3ee48b6af49cf534ca2f481ecc484b156a41451d

upstream commit 3ee48b6af49cf534ca2f481ecc484b156a41451d adjusted to apply to 2.6.32-89.el6

Comment 7 Neil Horman 2011-02-18 14:02:30 EST

ack, looks reasonable, thanks!

Comment 9 Aristeu Rozanski 2011-03-10 12:57:46 EST

Patch(es) available on kernel-2.6.32-121.el6

Comment 13 Martin Prpič 2011-04-12 08:43:24 EDT

    Technical note added. If any revisions are required, please edit the "Technical Notes" field
    accordingly. All revisions will be proofread by the Engineering Content Services team.
    
    New Contents:
Reading the /proc/vmcore file was previously significantly slower on a Red Hat Enterprise Linux 6 system when compared to a Red Hat Enterprise Linux 5 system. This update enables caching of memory accesses; reading of the /proc/vmcore file is now noticeably faster.

Comment 15 errata-xmlrpc 2011-05-19 08:50:00 EDT

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 therefore 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/RHSA-2011-0542.html

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