--On Tuesday, October 22, 2002 22:37:10 -0700 Andrew Morton
<akpm@digeo.com> wrote:

> 
> I'm getting lockups in install_page() with shared pagetables
> enabled.  I haven't really delved into it.  It happens under
> heavy memory pressure on SMP.
> 
> Ingo's new patch is using install_page much more than we
> used to (I don't think I've ever run it before), so we're
> running fairly untested codepaths here.

As Ingo said, he added install_page.

> I tried this:
> 
> (snip)
> 
> Because doing a pte_page_lock(ptepage) and then losing
> track of the page we just locked looks fishy.  Didn't
> help though.

The code was correct.  pte_unshare moves the lock to the new pte page if it
installs one.  I know that's not real clean, but it eliminates multiple
unlock/relock sequences.

> Dave could you please review the code in there?  It's probably
> something simple.

I found the problem.  In memory.c:do_file_page it unlocks the
page_table_lock.  In the new locking scheme, it's actually the
pte_page_lock that's held instead.

The patch to fix this is attached.

Dave McCracken

======================================================================
Dave McCracken          IBM Linux Base Kernel Team      1-512-838-3059
dmccr@us.ibm.com                                        T/L   678-3059