Re: [PATCH v3 3/3] mm: use numa_mem_id() in alloc_pages_node()
On 07/30/2015 07:41 PM, Johannes Weiner wrote: On Thu, Jul 30, 2015 at 06:34:31PM +0200, Vlastimil Babka wrote: numa_mem_id() is able to handle allocation from CPUs on memory-less nodes, so it's a more robust fallback than the currently used numa_node_id(). Won't it fall through to the next closest memory node in the zonelist anyway? Right, I would expect the zonelist of memoryless node to be the same as of the closest node. Documentation/vm/numa seems to agree. Is this for callers doing NUMA_NO_NODE with __GFP_THISZONE? I guess that's the only scenario where that matters, yeah. And there might well be no such caller now, but maybe some will sneak in without the author testing on a system with memoryless node. Note that with !CONFIG_HAVE_MEMORYLESS_NODES, numa_mem_id() just does numa_node_id(). So yeah I think a more robust fallback is correct :) But let's put it explicitly in changelog then: 8 alloc_pages_node() might fail when called with NUMA_NO_NODE and __GFP_THISNODE on a CPU belonging to a memoryless node. To make the local-node fallback more robust and prevent such situations, use numa_mem_id(), which was introduced for similar scenarios in the slab context. ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
[PATCH v3 3/3] mm: use numa_mem_id() in alloc_pages_node()
numa_mem_id() is able to handle allocation from CPUs on memory-less nodes,
so it's a more robust fallback than the currently used numa_node_id().
Suggested-by: Christoph Lameter c...@linux.com
Signed-off-by: Vlastimil Babka vba...@suse.cz
Acked-by: David Rientjes rient...@google.com
Acked-by: Mel Gorman mgor...@techsingularity.net
---
include/linux/gfp.h | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/include/linux/gfp.h b/include/linux/gfp.h
index 4a12cae2..f92cbd2 100644
--- a/include/linux/gfp.h
+++ b/include/linux/gfp.h
@@ -318,13 +318,14 @@ __alloc_pages_node(int nid, gfp_t gfp_mask, unsigned int
order)
/*
* Allocate pages, preferring the node given as nid. When nid == NUMA_NO_NODE,
- * prefer the current CPU's node. Otherwise node must be valid and online.
+ * prefer the current CPU's closest node. Otherwise node must be valid and
+ * online.
*/
static inline struct page *alloc_pages_node(int nid, gfp_t gfp_mask,
unsigned int order)
{
if (nid == NUMA_NO_NODE)
- nid = numa_node_id();
+ nid = numa_mem_id();
return __alloc_pages_node(nid, gfp_mask, order);
}
--
2.4.6
___
Linuxppc-dev mailing list
Linuxppc-dev@lists.ozlabs.org
https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: [PATCH v3 3/3] mm: use numa_mem_id() in alloc_pages_node()
On Thu, Jul 30, 2015 at 06:34:31PM +0200, Vlastimil Babka wrote: numa_mem_id() is able to handle allocation from CPUs on memory-less nodes, so it's a more robust fallback than the currently used numa_node_id(). Won't it fall through to the next closest memory node in the zonelist anyway? Is this for callers doing NUMA_NO_NODE with __GFP_THISZONE? ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: [PATCH v3 3/3] mm: use numa_mem_id() in alloc_pages_node()
On Thu, 30 Jul 2015, Vlastimil Babka wrote: numa_mem_id() is able to handle allocation from CPUs on memory-less nodes, so it's a more robust fallback than the currently used numa_node_id(). Suggested-by: Christoph Lameter c...@linux.com Signed-off-by: Vlastimil Babka vba...@suse.cz Acked-by: David Rientjes rient...@google.com Acked-by: Mel Gorman mgor...@techsingularity.net You can add my ack too if it helps. Acked-by: Christoph Lameter c...@linux.com ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
