Bug 178242 - mmap wastes too much virtual address space on x86
Summary: mmap wastes too much virtual address space on x86
Keywords:
Status: CLOSED WONTFIX
Alias: None
Product: Red Hat Enterprise Linux 3
Classification: Red Hat
Component: kernel
Version: 3.0
Hardware: i386
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Larry Woodman
QA Contact: Brian Brock
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2006-01-18 19:44 UTC by Larry Woodman
Modified: 2007-11-30 22:07 UTC (History)
1 user (show)

Fixed In Version:
Doc Type: Enhancement
Doc Text:
Clone Of:
Environment:
Last Closed: 2006-12-11 22:03:14 UTC
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)
program to illustrate address spave waste. (3.68 KB, text/plain)
2006-01-18 19:46 UTC, Larry Woodman 		no flags Details
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Description Larry Woodman 2006-01-18 19:44:37 UTC 
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 19:46:15 UTC 
Created attachment 123398 [details]
program to illustrate address spave waste.
Comment 2 Larry Woodman 2006-12-11 21:06:33 UTC 
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 22:03:14 UTC 
Closing based on last comment.
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