Bug 178242 – mmap wastes too much virtual address space on x86

Bug 178242 - mmap wastes too much virtual address space on x86

Summary:	mmap wastes too much virtual address space on x86

Status:	CLOSED WONTFIX

Aliases:	None

Product:	Red Hat Enterprise Linux 3
Classification:	Red Hat
Component:	kernel (Show other bugs)
Sub Component:
Version:	3.0
Hardware:	i386 Linux

Priority	medium Severity medium
Target Milestone:	---
Target Release:	---
Assigned To:	Larry Woodman
QA Contact:	Brian Brock
Docs Contact:

URL:
Whiteboard:
Keywords:	FutureFeature

Depends On:
Blocks:
	Show dependency tree / graph

Reported:	2006-01-18 14:44 EST by Larry Woodman
Modified:	2007-11-30 17:07 EST (History)
CC List:	1 user (show)

See Also:
Fixed In Version:
Doc Type:	Enhancement
Doc Text:
Story Points:	---
Clone Of:
Environment:
Last Closed:	2006-12-11 17:03:14 EST
Type:	---
Regression:	---
Mount Type:	---
Documentation:	---
CRM:
Verified Versions:
Category:	---
oVirt Team:	---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---

Attachments	(Terms of Use)
program to illustrate address spave waste. (3.68 KB, text/plain) 2006-01-18 14:46 EST, Larry Woodman	no flags	Details
Add an attachment (proposed patch, testcase, etc.)

Groups: None (edit)

Description Larry Woodman 2006-01-18 14:44:37 EST

From Bugzilla Helper:
User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.4.2) Gecko/20040301

Description of problem:

The arch_get_unmapped_nonexecutable_area() function relies on the non_executable_cache to locate where mmap()'d and malloc()'d memory will be allocated.  While this results in fast searches through a virtual address space, it wastes too much virtual address space for 32-bit systems and applications.

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


How reproducible:
Always

Steps to Reproduce:
1.Run the attached program 
2.
3.
  

Actual Results:  program terminated after only 100 mmap()s

Expected Results:  Program should sucessfully mmap() about 800 times

Additional info:

Comment 1 Larry Woodman 2006-01-18 14:46:15 EST

Created attachment 123398 [details]
program to illustrate address spave waste.

Comment 2 Larry Woodman 2006-12-11 16:06:33 EST

We should probably just close this BZ as WONTFIX because patch
1205.lwoodman.x86-mmap-vas-waste.patch was rejected.

Larry Woodman

Comment 3 Ernie Petrides 2006-12-11 17:03:14 EST

Closing based on last comment.

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