2022-03-25 18:35:04

by Zi Yan

[permalink] [raw]
Subject: [PATCH v9 4/5] mm: cma: use pageblock_order as the single alignment

From: Zi Yan <[email protected]>

Now alloc_contig_range() works at pageblock granularity. Change CMA
allocation, which uses alloc_contig_range(), to use pageblock_nr_pages
alignment.

Signed-off-by: Zi Yan <[email protected]>
---
include/linux/cma.h | 4 ++--
include/linux/mmzone.h | 5 +----
mm/page_alloc.c | 4 ++--
3 files changed, 5 insertions(+), 8 deletions(-)

diff --git a/include/linux/cma.h b/include/linux/cma.h
index a6f637342740..63873b93deaa 100644
--- a/include/linux/cma.h
+++ b/include/linux/cma.h
@@ -17,11 +17,11 @@
#define CMA_MAX_NAME 64

/*
- * TODO: once the buddy -- especially pageblock merging and alloc_contig_range()
+ * the buddy -- especially pageblock merging and alloc_contig_range()
* -- can deal with only some pageblocks of a higher-order page being
* MIGRATE_CMA, we can use pageblock_nr_pages.
*/
-#define CMA_MIN_ALIGNMENT_PAGES MAX_ORDER_NR_PAGES
+#define CMA_MIN_ALIGNMENT_PAGES pageblock_nr_pages
#define CMA_MIN_ALIGNMENT_BYTES (PAGE_SIZE * CMA_MIN_ALIGNMENT_PAGES)

struct cma;
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 962b14d403e8..0725c50ca0cb 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -54,10 +54,7 @@ enum migratetype {
*
* The way to use it is to change migratetype of a range of
* pageblocks to MIGRATE_CMA which can be done by
- * __free_pageblock_cma() function. What is important though
- * is that a range of pageblocks must be aligned to
- * MAX_ORDER_NR_PAGES should biggest page be bigger than
- * a single pageblock.
+ * __free_pageblock_cma() function.
*/
MIGRATE_CMA,
#endif
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 57ebc9e41414..e5b545d60456 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -9064,8 +9064,8 @@ int __alloc_contig_migrate_range(struct compact_control *cc,
* be either of the two.
* @gfp_mask: GFP mask to use during compaction
*
- * The PFN range does not have to be pageblock or MAX_ORDER_NR_PAGES
- * aligned. The PFN range must belong to a single zone.
+ * The PFN range does not have to be pageblock aligned. The PFN range must
+ * belong to a single zone.
*
* The first thing this routine does is attempt to MIGRATE_ISOLATE all
* pageblocks in the range. Once isolated, the pageblocks should not
--
2.35.1