Re: [PATCH 7/8] memory-hotplug: enable memory hotplug to handle hugepage

[Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>]

On Wed, Jul 24, 2013 at 02:10:07PM +0800, Wanpeng Li wrote:
...
> >diff --git v3.11-rc1.orig/mm/page_isolation.c v3.11-rc1/mm/page_isolation.c
> >index 383bdbb..cf48ef6 100644
> >--- v3.11-rc1.orig/mm/page_isolation.c
> >+++ v3.11-rc1/mm/page_isolation.c
> >@@ -6,6 +6,7 @@
> > #include <linux/page-isolation.h>
> > #include <linux/pageblock-flags.h>
> > #include <linux/memory.h>
> >+#include <linux/hugetlb.h>
> > #include "internal.h"
> >
> > int set_migratetype_isolate(struct page *page, bool skip_hwpoisoned_pages)
> >@@ -252,6 +253,10 @@ struct page *alloc_migrate_target(struct page *page, unsigned long private,
> > {
> > 	gfp_t gfp_mask = GFP_USER | __GFP_MOVABLE;
> >
> >+	if (PageHuge(page))
> >+		return alloc_huge_page_node(page_hstate(compound_head(page)),
> >+					    numa_node_id());
> >+
> 
> Why specify current node? Maybe current node is under remove.

Yes. One difficulty is that this function doesn't have vma and we can't
rely on mempolicy for node choice. I think that simply choosing the next
node by incrementing node id can be a work around, though it's not the
best solution.

Thanks,
Naoya Horiguchi

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