[PATCH] netfs: Add retry stat counters

David Howells
2025-01-28T09:33:24Z

Here's an additional patch to allow stats on the number of retries to be
obtained. This isn't a fix per se.

David
---
From: David Howells <dhowells@redhat.com>

netfs: Add retry stat counters

Add stat counters to count the number of request and subrequest retries and
display them in /proc/fs/netfs/stats.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
---
fs/netfs/internal.h | 4 ++++
fs/netfs/read_retry.c | 3 +++
fs/netfs/stats.c | 9 +++++++++
fs/netfs/write_issue.c | 1 +
fs/netfs/write_retry.c | 2 ++
5 files changed, 19 insertions(+)

diff --git a/fs/netfs/internal.h b/fs/netfs/internal.h
index eb76f98c894b..1c4f953c3d68 100644
--- a/fs/netfs/internal.h
+++ b/fs/netfs/internal.h
@@ -135,6 +135,8 @@ extern atomic_t netfs_n_rh_write_begin;
extern atomic_t netfs_n_rh_write_done;
extern atomic_t netfs_n_rh_write_failed;
extern atomic_t netfs_n_rh_write_zskip;
+extern atomic_t netfs_n_rh_retry_read_req;
+extern atomic_t netfs_n_rh_retry_read_subreq;
extern atomic_t netfs_n_wh_buffered_write;
extern atomic_t netfs_n_wh_writethrough;
extern atomic_t netfs_n_wh_dio_write;
@@ -147,6 +149,8 @@ extern atomic_t netfs_n_wh_upload_failed;
extern atomic_t netfs_n_wh_write;
extern atomic_t netfs_n_wh_write_done;
extern atomic_t netfs_n_wh_write_failed;
+extern atomic_t netfs_n_wh_retry_write_req;
+extern atomic_t netfs_n_wh_retry_write_subreq;
extern atomic_t netfs_n_wb_lock_skip;
extern atomic_t netfs_n_wb_lock_wait;
extern atomic_t netfs_n_folioq;
diff --git a/fs/netfs/read_retry.c b/fs/netfs/read_retry.c
index 8316c4533a51..0f294b26e08c 100644
--- a/fs/netfs/read_retry.c
+++ b/fs/netfs/read_retry.c
@@ -14,6 +14,7 @@ static void netfs_reissue_read(struct netfs_io_request *rreq,
{
__clear_bit(NETFS_SREQ_MADE_PROGRESS, &subreq->flags);
__set_bit(NETFS_SREQ_IN_PROGRESS, &subreq->flags);
+ netfs_stat(&netfs_n_rh_retry_read_subreq);
subreq->rreq->netfs_ops->issue_read(subreq);
}

@@ -260,6 +261,8 @@ void netfs_retry_reads(struct netfs_io_request *rreq)
struct netfs_io_stream *stream = &rreq->io_streams[0];
DEFINE_WAIT(myself);

+ netfs_stat(&netfs_n_rh_retry_read_req);
+
set_bit(NETFS_RREQ_RETRYING, &rreq->flags);

/* Wait for all outstanding I/O to quiesce before performing retries as
diff --git a/fs/netfs/stats.c b/fs/netfs/stats.c
index f1af344266cc..ab6b916addc4 100644
--- a/fs/netfs/stats.c
+++ b/fs/netfs/stats.c
@@ -29,6 +29,8 @@ atomic_t netfs_n_rh_write_begin;
atomic_t netfs_n_rh_write_done;
atomic_t netfs_n_rh_write_failed;
atomic_t netfs_n_rh_write_zskip;
+atomic_t netfs_n_rh_retry_read_req;
+atomic_t netfs_n_rh_retry_read_subreq;
atomic_t netfs_n_wh_buffered_write;
atomic_t netfs_n_wh_writethrough;
atomic_t netfs_n_wh_dio_write;
@@ -41,6 +43,8 @@ atomic_t netfs_n_wh_upload_failed;
atomic_t netfs_n_wh_write;
atomic_t netfs_n_wh_write_done;
atomic_t netfs_n_wh_write_failed;
+atomic_t netfs_n_wh_retry_write_req;
+atomic_t netfs_n_wh_retry_write_subreq;
atomic_t netfs_n_wb_lock_skip;
atomic_t netfs_n_wb_lock_wait;
atomic_t netfs_n_folioq;
@@ -81,6 +85,11 @@ int netfs_stats_show(struct seq_file *m, void *v)
atomic_read(&netfs_n_wh_write),
atomic_read(&netfs_n_wh_write_done),
atomic_read(&netfs_n_wh_write_failed));
+ seq_printf(m, "Retries: rq=%u rs=%u wq=%u ws=%u\n",
+ atomic_read(&netfs_n_rh_retry_read_req),
+ atomic_read(&netfs_n_rh_retry_read_subreq),
+ atomic_read(&netfs_n_wh_retry_write_req),
+ atomic_read(&netfs_n_wh_retry_write_subreq));
seq_printf(m, "Objs : rr=%u sr=%u foq=%u wsc=%u\n",
atomic_read(&netfs_n_rh_rreq),
atomic_read(&netfs_n_rh_sreq),
diff --git a/fs/netfs/write_issue.c b/fs/netfs/write_issue.c
index 69727411683e..77279fc5b5a7 100644
--- a/fs/netfs/write_issue.c
+++ b/fs/netfs/write_issue.c
@@ -253,6 +253,7 @@ void netfs_reissue_write(struct netfs_io_stream *stream,
subreq->retry_count++;
__clear_bit(NETFS_SREQ_MADE_PROGRESS, &subreq->flags);
__set_bit(NETFS_SREQ_IN_PROGRESS, &subreq->flags);
+ netfs_stat(&netfs_n_wh_retry_write_subreq);
netfs_do_issue_write(stream, subreq);
}

diff --git a/fs/netfs/write_retry.c b/fs/netfs/write_retry.c
index c841a851dd73..545d33079a77 100644
--- a/fs/netfs/write_retry.c
+++ b/fs/netfs/write_retry.c
@@ -203,6 +203,8 @@ void netfs_retry_writes(struct netfs_io_request *wreq)
struct netfs_io_stream *stream;
int s;

+ netfs_stat(&netfs_n_wh_retry_write_req);
+
/* Wait for all outstanding I/O to quiesce before performing retries as
* we may need to renegotiate the I/O sizes.
*/