| Message ID | 20130830132437.4947.12826.stgit@srivatsabhat.in.ibm.com (mailing list archive) |
|---|---|
| State | RFC, archived |
| Headers | show |
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index e303351..1312546 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1016,8 +1016,10 @@ static void __del_from_region_allocator(struct zone *zone, unsigned int order, reg_area = ®_alloc->region[region_id].region_area[order]; ralloc_list = ®_area->list; - list_for_each_entry(page, ralloc_list, lru) + list_for_each_entry(page, ralloc_list, lru) { set_freepage_migratetype(page, migratetype); + set_pageblock_migratetype(page, migratetype); + } free_list = &zone->free_area[order].free_list[migratetype];
We would like to maintain memory regions such that all memory pertaining to given a memory region serves allocations of a single migratetype. IOW, we don't want to permanently mix allocations of different migratetypes within the same region. So, when allocating a region from the region allocator to the page allocator, set the pageblock migratetype of all that memory to the migratetype for which the page allocator requested memory. Note that this still allows temporary sharing of pages between different migratetypes; it just ensures that there is no *permanent* mixing of migratetypes within a given memory region. An important advantage to be noted here is that the region allocator doesn't have to manage memory in a granularity lesser than a memory region, in *any* situation. This is because the freepage migratetype and the fallback mechanism allows temporary sharing of free memory between different migratetypes when the system is short on memory, but eventually all the memory gets freed to the original migratetype (because we set the pageblock migratetype of all the freepages appropriately when allocating regions). This greatly simplifies the design of the region allocator, since it doesn't have to keep track of memory in smaller chunks than a memory region. Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> --- mm/page_alloc.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html