On 11/11/2010 09:44 PM, Lee Schermerhorn wrote:
This series of patches implements page migration in the fault path.
!!! N.B., Need to consider iteraction with KSM and Transparent Huge
!!! Pages.
The basic idea is that when a fault handler such as do_swap_page()
finds a cached page with zero mappings that is otherwise "stable"--
e.g., no I/O in progress--this is a good opportunity to check whether the
page resides on the node indicated by the mempolicy in the current context.
We only attempt to migrate when there are zero mappings because 1) we can
easily migrate the page--don't have to go through the effort of removing
all mappings and 2) default policy--a common case--can give different
answers from different tasks running on different nodes. Checking the
policy when there are zero mappings effectively implements a "first touch"
placement policy.
A couple of kvm-related notes:
- kvm page faults are significantly more expensive than ordinary page
faults; this will affect the cost/benefit tradeoff
- kvm faults go through get_user_pages_fast(), not the ordinary fault
path. Will the code handle this?
--
error compiling committee.c: too many arguments to function
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