PATCH 0/3 hugetlb: constrain allocation/free based on task mempolicy Against: 25jun09 mmotm atop the "hugetlb: balance freeing..." series This is V2 of a series of patches to constrain the allocation and freeing of persistent huge pages using the task NUMA mempolicy of the task modifying "nr_hugepages". This series is based on Mel Gorman's suggestion to use task mempolicy. V2 addresses review comments from Mel Gorman and Andrew Morton. See the patch description of patch 2/3. I have some concerns about a subtle change in behavior [see patch 2/3 and the updated documentation] and the fact that this mechanism ignores some of the semantics of the mempolicy mode [again, see the doc]. However, this method seems to work fairly well. And, IMO, the resulting code doesn't look all that bad. A couple of limitations in this version: 1) I haven't implemented a boot time parameter to constrain the boot time allocation of huge pages. This can be added if anyone feels strongly that it is required. 2) I have not implemented a per node nr_overcommit_hugepages as David Rientjes and I discussed earlier. Again, this can be added and specific nodes can be addressed using the mempolicy as this series does for allocation and free. However, after some experience with the libhugetlbfs test suite, specifically attempting to run the test suite constrained by mempolicy and a cpuset, I'm thinking that per node overcommit limits might not be such a good idea. This would require an application [or the library] to sum the per node limits over the allowed nodes and possibly compare to global limits to determine the available resources. Per cpuset limits might work better. This are requires more investigation, but this patch series doesn't seem to make things worse than they already are in this regard. -- To unsubscribe from this list: send the line "unsubscribe linux-numa" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
