From: Jason Xing <kernelxing@xxxxxxxxxxx>
In this version, only support getting the counter for buffer full and
implement the framework of how it works.
Users can pass certain flag to fetch what field/statistics they expect
to know. Each time it only returns one result. So do not pass multiple
flags.
Reviewed-by: Yushan Zhou <katrinzhou@xxxxxxxxxxx>
Signed-off-by: Jason Xing <kernelxing@xxxxxxxxxxx>
---
v3
1. rename and adjust relay_stats()
2. move rbuf init out of if statement
v2
1. refactor relay_dump() and make it only return a pure size_t result
of the value that users specifies.
2. revise the commit log.
---
include/linux/relay.h | 7 +++++++
kernel/relay.c | 30 ++++++++++++++++++++++++++++++
2 files changed, 37 insertions(+)
diff --git a/include/linux/relay.h b/include/linux/relay.h
index cd77eb285a48..5310967f9d74 100644
--- a/include/linux/relay.h
+++ b/include/linux/relay.h
@@ -31,6 +31,12 @@
/*
* Relay buffer statistics
*/
+enum {
+ RELAY_STATS_BUF_FULL = (1 << 0),
+
+ RELAY_STATS_LAST = RELAY_STATS_BUF_FULL,
+};
+
struct rchan_buf_stats
{
unsigned int full_count; /* counter for buffer full */
@@ -167,6 +173,7 @@ struct rchan *relay_open(const char *base_filename,
void *private_data);
extern void relay_close(struct rchan *chan);
extern void relay_flush(struct rchan *chan);
+size_t relay_stats(struct rchan *chan, int flags);
extern void relay_subbufs_consumed(struct rchan *chan,
unsigned int cpu,
size_t consumed);
diff --git a/kernel/relay.c b/kernel/relay.c
index eb3f630f3896..fd70d0e03216 100644
--- a/kernel/relay.c
+++ b/kernel/relay.c
@@ -701,6 +701,36 @@ void relay_flush(struct rchan *chan)
}
EXPORT_SYMBOL_GPL(relay_flush);
+/**
+ * relay_stats - get channel buffer statistics
+ * @chan: the channel
+ * @flags: select particular information to get
+ *
+ * Returns the count of certain field that caller specifies.
+ */
+size_t relay_stats(struct rchan *chan, int flags)
+{
+ unsigned int i, count = 0;
+ struct rchan_buf *rbuf;
+
+ if (!chan || flags > RELAY_STATS_LAST)
+ return 0;
+
+ if (chan->is_global) {
+ rbuf = *per_cpu_ptr(chan->buf, 0);
+ if (flags & RELAY_STATS_BUF_FULL)
+ count = rbuf->stats.full_count;
+ } else {
+ for_each_online_cpu(i) {
+ rbuf = *per_cpu_ptr(chan->buf, i);
+ if (rbuf && flags & RELAY_STATS_BUF_FULL)
+ count += rbuf->stats.full_count;
+ }
+ }
+
+ return count;
+}
+
/**
* relay_file_open - open file op for relay files
* @inode: the inode
--
2.43.5
