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

From: David Howells
Date: Fri Oct 22 2021 - 15:04:52 EST


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

Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
cc: linux-cachefs@xxxxxxxxxx
---

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 */