Red Hat Bugzilla – Bug 178242
mmap wastes too much virtual address space on x86
Last modified: 2007-11-30 17:07:09 EST
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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):
Steps to Reproduce:
1.Run the attached program
Actual Results: program terminated after only 100 mmap()s
Expected Results: Program should sucessfully mmap() about 800 times
Created attachment 123398 [details]
program to illustrate address spave waste.
We should probably just close this BZ as WONTFIX because patch
1205.lwoodman.x86-mmap-vas-waste.patch was rejected.
Closing based on last comment.