Messages in this thread | | | Date | Tue, 11 May 2010 17:15:16 +0100 | From | Mel Gorman <> | Subject | Re: [PATCH 2/2] mm,migration: Avoid race between shift_arg_pages() and rmap_walk() during migration by not migrating temporary stacks |
| |
On Tue, May 11, 2010 at 10:56:00AM -0500, Christoph Lameter wrote: > On Tue, 11 May 2010, Mel Gorman wrote: > > > Or just identify the temporary stack from the migration side instead of > > adding to the cost of exec? > > Adding one off checks to a generic mechanism isnt really clean > programming. Using the provided means of disabling a generic mechanism is. >
Andrea's solution is likely lighter than yours as it is one kmalloc and an insertion into the VM as opposed to a page table walk with reference counting. Better yet, it exists as a patch that has been tested and it fits in with the generic mechanism by guaranteeing that rmap_walk finds all the migration PTEs during the second walk.
The problem remains the same - that class of solution increases the cost of a common operation (exec) to keep a much less operation (migration) happy.
-- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab
| |