[PATCH 2.5.63] Make objrmap mapcount non-atomic

From: Dave McCracken (dmccr@us.ibm.com)
Date: Tue Mar 04 2003 - 13:32:11 EST


--On Monday, March 03, 2003 14:15:18 -0800 Andrew Morton <akpm@digeo.com>
wrote:

> Well why not make mapcount an "int" and move the places where it is
> modified inside pte_chain_lock()?
>
> That does not increase the number of atomic operations, and it makes me
> stop wondering if this:
>
> if (atomic_read(&page->pte.mapcount) == 0)
> inc_page_state(nr_mapped);
>
> is racy ;)

That would be entirely too easy a solution :)

You're entirely right, of course. Here's the patch that makes it an int
instead of atomic, with the appropriate locking.

Dave

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



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