[PATCH v2 1/4] mm: introduce alloc_contig_mode

[Minchan Kim <minchan@kernel.org>]

There are demands to control how hard alloc_contig_range try to
increase allocation success ratio. This patch abstract it by
adding new enum mode parameter in alloc_contig_range.
New API in next patch will add up new mode there to control it.

This patch shouldn't change any existing behavior.

Suggested-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Minchan Kim <minchan@kernel.org>
---
 drivers/virtio/virtio_mem.c | 2 +-
 include/linux/gfp.h         | 8 +++++++-
 mm/cma.c                    | 3 ++-
 mm/page_alloc.c             | 6 ++++--
 4 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c
index 9fc9ec4a25f5..5585fc67b65e 100644
--- a/drivers/virtio/virtio_mem.c
+++ b/drivers/virtio/virtio_mem.c
@@ -1148,7 +1148,7 @@ static int virtio_mem_fake_offline(unsigned long pfn, unsigned long nr_pages)
 	 */
 	for (retry_count = 0; retry_count < 5; retry_count++) {
 		rc = alloc_contig_range(pfn, pfn + nr_pages, MIGRATE_MOVABLE,
-					GFP_KERNEL);
+					GFP_KERNEL, ALLOC_CONTIG_NORMAL);
 		if (rc == -ENOMEM)
 			/* whoops, out of memory */
 			return rc;
diff --git a/include/linux/gfp.h b/include/linux/gfp.h
index c603237e006c..ad5872699692 100644
--- a/include/linux/gfp.h
+++ b/include/linux/gfp.h
@@ -624,9 +624,15 @@ static inline bool pm_suspended_storage(void)
 #endif /* CONFIG_PM_SLEEP */
 
 #ifdef CONFIG_CONTIG_ALLOC
+enum alloc_contig_mode {
+	/* try several ways to increase success ratio of memory allocation */
+	ALLOC_CONTIG_NORMAL,
+};
+
 /* The below functions must be run on a range from a single zone. */
 extern int alloc_contig_range(unsigned long start, unsigned long end,
-			      unsigned migratetype, gfp_t gfp_mask);
+			      unsigned migratetype, gfp_t gfp_mask,
+			      enum alloc_contig_mode mode);
 extern struct page *alloc_contig_pages(unsigned long nr_pages, gfp_t gfp_mask,
 				       int nid, nodemask_t *nodemask);
 #endif
diff --git a/mm/cma.c b/mm/cma.c
index 3692a34e2353..8010c1ba04b0 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -454,7 +454,8 @@ struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align,
 
 		pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
 		ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA,
-				     GFP_KERNEL | (no_warn ? __GFP_NOWARN : 0));
+				     GFP_KERNEL | (no_warn ? __GFP_NOWARN : 0),
+				     ALLOC_CONTIG_NORMAL);
 
 		if (ret == 0) {
 			page = pfn_to_page(pfn);
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index f91df593bf71..adfbfd95fbc3 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -8533,6 +8533,7 @@ static void __alloc_contig_clear_range(unsigned long start_pfn,
  *			be either of the two.
  * @gfp_mask:	GFP mask to use during compaction. __GFP_ZERO clears allocated
  *		pages.
+ * @mode:	how hard it will try to increase allocation success ratio
  *
  * The PFN range does not have to be pageblock or MAX_ORDER_NR_PAGES
  * aligned.  The PFN range must belong to a single zone.
@@ -8546,7 +8547,8 @@ static void __alloc_contig_clear_range(unsigned long start_pfn,
  * need to be freed with free_contig_range().
  */
 int alloc_contig_range(unsigned long start, unsigned long end,
-		       unsigned migratetype, gfp_t gfp_mask)
+		       unsigned migratetype, gfp_t gfp_mask,
+		       enum alloc_contig_mode mode)
 {
 	unsigned long outer_start, outer_end;
 	unsigned int order;
@@ -8689,7 +8691,7 @@ static int __alloc_contig_pages(unsigned long start_pfn,
 	unsigned long end_pfn = start_pfn + nr_pages;
 
 	return alloc_contig_range(start_pfn, end_pfn, MIGRATE_MOVABLE,
-				  gfp_mask);
+				  gfp_mask, ALLOC_CONTIG_NORMAL);
 }
 
 static bool pfn_range_valid_contig(struct zone *z, unsigned long start_pfn,
-- 
2.29.2.454.gaff20da3a2-goog