Bug 964450

Summary:	mallopt: There is no env variable to control M_MXFAST
Product:	Red Hat Enterprise Linux 6	Reporter:	Sergio Martins <iamsergio>
Component:	glibc	Assignee:	Carlos O'Donell <codonell>
Status:	CLOSED WONTFIX	QA Contact:	qe-baseos-tools-bugs
Severity:	unspecified	Docs Contact:
Priority:	unspecified
Version:	6.6	CC:	fweimer, mfranc, mnewsome, pfrankli
Target Milestone:	rc
Target Release:	---
Hardware:	Unspecified
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
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Clone Of:		Environment:
Last Closed:	2015-10-19 19:20:20 UTC	Type:	Bug
Regression:	---	Mount Type:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description Sergio Martins 2013-05-18 18:31:23 UTC

mallopt() allows us to set several env variables to control the behaviour of the malloc implementation.

There doesn't seem to be one to control M_MXFAST, which would be very useful to tune the usage of fast bins without having to recompile the application.

Comment 7 Carlos O'Donell 2015-10-19 19:20:20 UTC

This is not going to get fixed in RHEL6. We don't risk deviate from upstream, and upstream doesn't want to add new environment variables without going through the tunables framework (consistent naming and scope for environment variables that change behaviour). Backporting this new framework to RHEL6 is a nonstarter. Therefore it is likely going to be the case that adjusting fastbin behaviour will always require an application rebuild for RHEL6, while newer RHEL releases will have support for this. As such I'm marking this CLOSED/WONTFIX.