mm/page_alloc: refactor out __alloc_contig_migrate_alloc()

__alloc_contig_migrate_alloc() can be used by memory-hotplug so refactor
it out (move + rename as a common name) into page_isolation.c.

[akpm@linux-foundation.org: checkpatch fixes]
Signed-off-by: Minchan Kim <minchan@kernel.org>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 11 insertions, 0 deletions

diff --git a/mm/page_isolation.c b/mm/page_isolation.c
index 5f34a9053ce0..f2f5b4818e94 100644
--- a/mm/page_isolation.c
+++ b/mm/page_isolation.c
@@ -255,3 +255,14 @@ int test_pages_isolated(unsigned long start_pfn, unsigned long end_pfn)
         spin_unlock_irqrestore(&zone->lock, flags);
         return ret ? 0 : -EBUSY;
 }
+
+struct page *alloc_migrate_target(struct page *page, unsigned long private,
+                                  int **resultp)
+{
+        gfp_t gfp_mask = GFP_USER | __GFP_MOVABLE;
+
+        if (PageHighMem(page))
+                gfp_mask |= __GFP_HIGHMEM;
+
+        return alloc_page(gfp_mask);
+}