Messages in this thread Patch in this message | | | From | Suresh Jayaraman <> | Subject | [09/31] mm: system wide ALLOC_NO_WATERMARK | Date | Thu, 1 Oct 2009 19:36:20 +0530 |
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From: Peter Zijlstra <a.p.zijlstra@chello.nl>
The reserve is proportionally distributed over all (!highmem) zones in the system. So we need to allow an emergency allocation access to all zones. In order to do that we need to break out of any mempolicy boundaries we might have.
In my opinion that does not break mempolicies as those are user oriented and not system oriented. That is, system allocations are not guaranteed to be within mempolicy boundaries. For instance IRQs don't even have a mempolicy.
So breaking out of mempolicy boundaries for 'rare' emergency allocations, which are always system allocations (as opposed to user) is ok.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de> --- mm/page_alloc.c | 5 +++++ 1 file changed, 5 insertions(+)
Index: mmotm/mm/page_alloc.c =================================================================== --- mmotm.orig/mm/page_alloc.c +++ mmotm/mm/page_alloc.c @@ -1775,6 +1775,11 @@ restart: rebalance: /* Allocate without watermarks if the context allows */ if (alloc_flags & ALLOC_NO_WATERMARKS) { + /* + * break out mempolicy boundaries + */ + zonelist = node_zonelist(numa_node_id(), gfp_mask); + page = __alloc_pages_high_priority(gfp_mask, order, zonelist, high_zoneidx, nodemask, preferred_zone, migratetype);
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