[PATCH v2 22/53] fscache: Provide read/write stat counters for the cache

[David Howells]

Provide read/write stat counters for the cache backend to use.

Signed-off-by: David Howells <dhowells at redhat.com>
cc: linux-cachefs at redhat.com
---

 fs/fscache/stats.c            |    9 +++++++++
 include/linux/fscache-cache.h |   10 ++++++++++
 2 files changed, 19 insertions(+)

diff --git a/fs/fscache/stats.c b/fs/fscache/stats.c
index 45b7636c7737..8d5ad6771498 100644
--- a/fs/fscache/stats.c
+++ b/fs/fscache/stats.c
@@ -37,6 +37,11 @@ atomic_t fscache_n_relinquishes;
 atomic_t fscache_n_relinquishes_retire;
 atomic_t fscache_n_relinquishes_dropped;
 
+atomic_t fscache_n_read;
+EXPORT_SYMBOL(fscache_n_read);
+atomic_t fscache_n_write;
+EXPORT_SYMBOL(fscache_n_write);
+
 /*
  * display the general statistics
  */
@@ -76,6 +81,10 @@ int fscache_stats_show(struct seq_file *m, void *v)
 		   atomic_read(&fscache_n_relinquishes_retire),
 		   atomic_read(&fscache_n_relinquishes_dropped));
 
+	seq_printf(m, "IO     : rd=%u wr=%u\n",
+		   atomic_read(&fscache_n_read),
+		   atomic_read(&fscache_n_write));
+
 	netfs_stats_show(m);
 	return 0;
 }
diff --git a/include/linux/fscache-cache.h b/include/linux/fscache-cache.h
index 2d57b85cfde3..6830f91ebaf4 100644
--- a/include/linux/fscache-cache.h
+++ b/include/linux/fscache-cache.h
@@ -172,6 +172,16 @@ void fscache_end_operation(struct netfs_cache_resources *cres)
 		ops->end_operation(cres);
 }
 
+#ifdef CONFIG_FSCACHE_STATS
+extern atomic_t fscache_n_read;
+extern atomic_t fscache_n_write;
+#define fscache_count_read() atomic_inc(&fscache_n_read)
+#define fscache_count_write() atomic_inc(&fscache_n_write)
+#else
+#define fscache_count_read() do {} while(0)
+#define fscache_count_write() do {} while(0)
+#endif
+
 extern struct workqueue_struct *fscache_wq;
 
 #endif /* _LINUX_FSCACHE_CACHE_H */