[OpenAFS-devel] Linux and memory mapped files hang the client, particularly when the client is OpenMosix.

George Talbot gtalbot@locuspharma.com
14 Jul 2003 11:34:12 -0400


OK.  This patch seems to work for me.  I'll let you know if I have any
further problems.

Thanks.

--George



On Thu, 2003-07-10 at 16:15, Derrick J Brashear wrote:
> On Thu, 10 Jul 2003, George Talbot wrote:
> 
> > Hi,
> >
> > We have a problem here with clients that make heavy use of mmap() on
> > files stored on an AFS server.  The program doing the mmap() access will
> > hang, as will top, ps, etc.  I'm using Linux kernel 2.4.20, with OpenAFS
> > 1.2.8, and OpenMosix, though I don't think it's OpenMosix, because if I
> > recompile the kernel without OpenMosix, I still get hangs, just not as
> > frequently.
> >
> > So I found this patch:
> >
> > https://lists.openafs.org/pipermail/openafs-devel/2002-December/003624.html
> 
> The patch we ended up applying to the head only, and not to any 1.2.x yet,
> was:
> http://www.openafs.org/cgi-bin/wdelta/linux-execsorwrites-at-close-20030328?diff&f=u
> 
> > This patch does not work for us.  I did some further investigation of
> > where the program is hanging.  The programs hang in
> > afs_linux_vma_close() right when this function tries to acquire a write
> []
> 
> > At this point afs_linux_vma_close() gets called because the application
> > is unmapping the file, acquires the AFS_GLOCK(), and blocks trying to
> > acquire the shared lock.
> >
> > Then, I believe that afs_GetDCache() runs again after the read
> > completes, tries to acquire the AFS_GLOCK() and blocks.
> 
> I will look at this soon unless someone beats me to it.
> 
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