[PATCH net-next 2/6] net: page_pool: Add a stat for the slow alloc path

[Joe Damato <jdamato@fastly.com>]

Add a stat, 'slow', for the slow allocation path. A static inline accessor
function is exposed for accessing this stat.

Signed-off-by: Joe Damato <jdamato@fastly.com>
---
 include/net/page_pool.h | 10 ++++++++++
 net/core/page_pool.c    |  6 ++++--
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/include/net/page_pool.h b/include/net/page_pool.h
index 3ae3dc4..b5691ee 100644
--- a/include/net/page_pool.h
+++ b/include/net/page_pool.h
@@ -82,6 +82,7 @@ struct pp_alloc_cache {
 struct page_pool_stats {
 	struct {
 		u64 fast; /* fast path allocations */
+		u64 slow; /* slow-path order-0 allocations */
 	} alloc;
 };
 
@@ -201,6 +202,10 @@ static inline u64 page_pool_stats_get_fast(struct page_pool *pool)
 	return pool->ps.alloc.fast;
 }
 
+static inline u64 page_pool_stats_get_slow(struct page_pool *pool)
+{
+	return pool->ps.alloc.slow;
+}
 #else
 static inline void page_pool_destroy(struct page_pool *pool)
 {
@@ -225,6 +230,11 @@ static inline u64 page_pool_stats_get_fast(struct page_pool *pool)
 {
 	return 0;
 }
+
+static inline u64 page_pool_stats_get_slow(struct page_pool *pool)
+{
+	return 0;
+}
 #endif
 
 void page_pool_put_page(struct page_pool *pool, struct page *page,
diff --git a/net/core/page_pool.c b/net/core/page_pool.c
index 84c9566..9dbe721 100644
--- a/net/core/page_pool.c
+++ b/net/core/page_pool.c
@@ -294,10 +294,12 @@ static struct page *__page_pool_alloc_pages_slow(struct page_pool *pool,
 	}
 
 	/* Return last page */
-	if (likely(pool->alloc.count > 0))
+	if (likely(pool->alloc.count > 0)) {
 		page = pool->alloc.cache[--pool->alloc.count];
-	else
+		pool->ps.alloc.slow++;
+	} else {
 		page = NULL;
+	}
 
 	/* When page just alloc'ed is should/must have refcnt 1. */
 	return page;
-- 
2.7.4