Messages in this thread | | | Date | Wed, 7 May 2008 16:39:44 -0700 | From | Nishanth Aravamudan <> | Subject | Re: [PATCH] x86: fix PAE pmd_bad bootup warning |
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On 06.05.2008 [21:36:59 +0100], Hugh Dickins wrote: > On Tue, 6 May 2008, Hans Rosenfeld wrote: > > On Tue, May 06, 2008 at 08:49:23PM +0100, Hugh Dickins wrote: > > > So Hans' original hugepage leak remains unexplained and unfixed. > > > Hans, did you find that hugepage leak with a standard kernel, or were > > > you perhaps trying out some hugepage-using patch of your own, without > > > marking the vma VM_HUGETLB? Or were you expecting the hugetlbfs file > > > to truncate itself once all mmappers had gone? If the standard kernel > > > leaks hugepages, I'm surprised the hugetlb guys don't know about it. > > > > I used a standard kernel (well, not quite, I had made some changes to > > the /proc/pid/pagemap code, but nothing that would affect the hugepage > > stuff) and some simple test program that would just mmap a hugepage. > > > > I expected that any hugepage that a process had mmapped would > > automatically be returned to the system when the process exits. That was > > not the case, the process exited and the hugepage was lost (unless I > > changed the program to explicitly munmap the hugepage before exiting). > > Removing the hugetlbfs file containing the hugepage also didn't free the > > page. > > Hmm. That doesn't fit with my experience: I've not found an explicit > munmap makes any difference (I wouldn't expect it to), but removing > the file once all openers gone does free everything up. I guess I'm > overlooking something more experienced hugepagers will soon light > upon.
Nothing strikes me immediately. What you described is what I expected. As Dave pointed out separately, are you able to unmount hugetlbfs at this point?
Hans, can you send out a sample application's source? What kernel were you testing on?
Thanks, Nish
-- Nishanth Aravamudan <nacc@us.ibm.com> IBM Linux Technology Center
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