This is the mail archive of the glibc-bugs@sourceware.org mailing list for the glibc project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

[Bug malloc/15321] New: malloc/free can't give the memory back to kernel when main_arena is discontinous


http://sourceware.org/bugzilla/show_bug.cgi?id=15321

             Bug #: 15321
           Summary: malloc/free can't give the memory back to kernel when
                    main_arena is discontinous
           Product: glibc
           Version: 2.17
            Status: NEW
          Severity: normal
          Priority: P2
         Component: malloc
        AssignedTo: unassigned@sourceware.org
        ReportedBy: xu.zhanxin@zte.com.cn
                CC: xu.zhanxin@zte.com.cn
    Classification: Unclassified


Created attachment 6957
  --> http://sourceware.org/bugzilla/attachment.cgi?id=6957
testcase for free can't give the memory back to kernel

Compile and run the attached test-case.

What it does:
1.Call malloc() to allocate 1024*4kB memory 
2.Call mmap()
3.Call malloc() and allocate 4096kB memory again
4.Call system to inspect the MemFree
5.Call free()
6.Call system to inspect the MemFree again

So,The will be free 8192kB memory,but it not.
-------------------------------------------------------------  
[xuzhanxin@localhost t-arena]$ gcc -o test-ok testcase.c -g -DUNMAP_OK
[xuzhanxin@localhost t-arena]$ gcc -o test-err testcase.c -g 

[xuzhanxin@localhost t-arena]$ ./test-ok 
    First malloc ok
    mmap ok
    Second malloc ok!
MemFree:      12630976 kB
    After free memory!
MemFree:      12638540 kB

[xuzhanxin@localhost t-arena]$ ./test-err
    First malloc ok
    mmap ok
    Second malloc ok!
MemFree:      12627628 kB
    After free memory!
MemFree:      12627380 kB

-- 
Configure bugmail: http://sourceware.org/bugzilla/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are on the CC list for the bug.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]