Re: [PATCH] Snapshot of shared page tables

[Dave McCracken <dmccr@us.ibm.com>]

--On Wednesday, October 02, 2002 18:51:41 +0200 Daniel Phillips
<phillips@arcor.de> wrote:

> Interesting, you substituted pte_page_lock(ptepage) for
> mm->page_table_lock. Could you wax poetic about that, please?

Sure.  If a pte page is shared, the mm->page_table_lock is not sufficient
to protect the rest of the page fault.  Therefore we need a lock at the pte
page level.  The mm->page_table_lock is held during the page fault until we
have a valid and locked pte page we're working on, then it's dropped for
the rest of the fault.

Feel free to poke holes in my logic, but I think it's the right locking
model for shared pte pages.

Dave McCracken

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

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