On 11/06/2012 04:14 AM, Mel Gorman wrote:
Note: This patch started as "mm/mpol: Create special PROT_NONE infrastructure" and preserves the basic idea but steals *very* heavily from "autonuma: numa hinting page faults entry points" for the actual fault handlers without the migration parts. The end result is barely recognisable as either patch so all Signed-off and Reviewed-bys are dropped. If Peter, Ingo and Andrea are ok with this version, I will re-add the signed-offs-by to reflect the history. In order to facilitate a lazy -- fault driven -- migration of pages, create a special transient PAGE_NUMA variant, we can then use the 'spurious' protection faults to drive our migrations from. Pages that already had an effective PROT_NONE mapping will not be detected
The patch itself is good, but the changelog needs a little fix. While you are defining _PAGE_NUMA to _PAGE_PROTNONE on x86, this may be different on other architectures. Therefore, the changelog should refer to PAGE_NUMA, not PROT_NONE.
to generate these 'spurious' faults for the simple reason that we cannot distinguish them on their protection bits, see pte_numa(). This isn't a problem since PROT_NONE (and possible PROT_WRITE with dirty tracking) aren't used or are rare enough for us to not care about their placement. Signed-off-by: Mel Gorman <mgorman@xxxxxxx>
Other than the changelog ... Reviewed-by: Rik van Riel <riel@xxxxxxxxxx> -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>