Losing pages from a mmap in threaded app vs. non-threaded

Sean McNeil sean at mcneil.com
Wed Nov 19 16:02:41 PST 2003


I think I know what the significance of the 8 pages is:  I essentially
write 8 pages at a time.  So I think that those pages are getting moved
from the proc vmspace map somehow after a thread writes to them.  Where
would the pages go?

On Wed, 2003-11-19 at 13:54, Jeff Roberson wrote:
> On Wed, 19 Nov 2003, Sean McNeil wrote:
> 
> > Yes, I mentioned this in my original post.  They all have the same
> > problem.
> 
> If you mount procfs you can look through the vm map for the process.  You
> want /proc/<pid>/map I believe.  Please note that the address returned by
> your driver routine is a physical address that will be mapped by the
> kernel at a new virtual address.  User-space can pass you only the offset
> into your memory range, and not a real address.
> 
> Cheers,
> Jeff
> 
> >
> > On Wed, 2003-11-19 at 13:38, Jeff Roberson wrote:
> > > On Wed, 19 Nov 2003, Daniel Eischen wrote:
> > >
> > > > On Wed, 19 Nov 2003, Sean McNeil wrote:
> > > >
> > > > > OK, would this happen to be 8 pages typically?
> > > >
> > > > It depends; see the comment and ascii art in
> > > > src/lib/libpthread/thread/thr_alloc.c.
> > >
> > > Have you tried with libc_r, libthr, and libkse?
> > >
> > > >
> > > > --
> > > > Dan Eischen
> > > >
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> > >
> >
> 



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