mm,migration: Avoid race between shift_arg_pages() and rmap_walk() during migration by not migrating temporary stacks
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From: Mel Gorman on 11 May 2010 12:20 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |