[PATCH] mm: vmstat: add cma statistics

[Minchan Kim]

Since CMA is used more widely, it's worth to have CMA
allocation statistics into vmstat. With it, we could
know how agressively system uses cma allocation and
how often it fails.

Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx>
---
 include/linux/vm_event_item.h |  3 +++
 mm/cma.c                      | 12 +++++++++---
 mm/vmstat.c                   |  4 ++++
 3 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/include/linux/vm_event_item.h b/include/linux/vm_event_item.h
index 18e75974d4e3..0c567014ce82 100644
--- a/include/linux/vm_event_item.h
+++ b/include/linux/vm_event_item.h
@@ -70,6 +70,9 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT,
 #endif
 #ifdef CONFIG_HUGETLB_PAGE
 		HTLB_BUDDY_PGALLOC, HTLB_BUDDY_PGALLOC_FAIL,
+#endif
+#ifdef CONFIG_CMA
+		CMA_ALLOC, CMA_ALLOC_FAIL,
 #endif
 		UNEVICTABLE_PGCULLED,	/* culled to noreclaim list */
 		UNEVICTABLE_PGSCANNED,	/* scanned for reclaimability */
diff --git a/mm/cma.c b/mm/cma.c
index 23d4a97c834a..ea1e39559526 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -434,14 +434,16 @@ struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align,
 	struct page *page = NULL;
 	int ret = -ENOMEM;
 
+	count_vm_event(CMA_ALLOC);
+
 	if (!cma || !cma->count || !cma->bitmap)
-		return NULL;
+		goto out;
 
 	pr_debug("%s(cma %p, count %zu, align %d)\n", __func__, (void *)cma,
 		 count, align);
 
 	if (!count)
-		return NULL;
+		goto out;
 
 	mask = cma_bitmap_aligned_mask(cma, align);
 	offset = cma_bitmap_aligned_offset(cma, align);
@@ -449,7 +451,7 @@ struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align,
 	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
 
 	if (bitmap_count > bitmap_maxno)
-		return NULL;
+		goto out;
 
 	for (;;) {
 		mutex_lock(&cma->lock);
@@ -506,6 +508,10 @@ struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align,
 	}
 
 	pr_debug("%s(): returned %p\n", __func__, page);
+out:
+	if (!page)
+		count_vm_event(CMA_ALLOC_FAIL);
+
 	return page;
 }
 
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 97fc32a53320..d8c32a33208d 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1305,6 +1305,10 @@ const char * const vmstat_text[] = {
 #ifdef CONFIG_HUGETLB_PAGE
 	"htlb_buddy_alloc_success",
 	"htlb_buddy_alloc_fail",
+#endif
+#ifdef CONFIG_CMA
+	"cma_alloc_success",
+	"cma_alloc_fail",
 #endif
 	"unevictable_pgs_culled",
 	"unevictable_pgs_scanned",
-- 
2.30.0.478.g8a0d178c01-goog