netfs: Gather stats

Gather statistics from the netfs interface that can be exported through a
seqfile.  This is intended to be called by a later patch when viewing
/proc/fs/fscache/stats.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-and-tested-by: Jeff Layton <jlayton@kernel.org>
Tested-by: Dave Wysochanski <dwysocha@redhat.com>
Tested-By: Marc Dionne <marc.dionne@auristor.com>
cc: Matthew Wilcox <willy@infradead.org>
cc: linux-mm@kvack.org
cc: linux-cachefs@redhat.com
cc: linux-afs@lists.infradead.org
cc: linux-nfs@vger.kernel.org
cc: linux-cifs@vger.kernel.org
cc: ceph-devel@vger.kernel.org
cc: v9fs-developer@lists.sourceforge.net
cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/161118139247.1232039.10556850937548511068.stgit@warthog.procyon.org.uk/ # rfc
Link: https://lore.kernel.org/r/161161034669.2537118.2761232524997091480.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/161340397101.1303470.17581910581108378458.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/161539539959.286939.6794352576462965914.stgit@warthog.procyon.org.uk/ # v4
Link: https://lore.kernel.org/r/161653797700.2770958.5801990354413178228.stgit@warthog.procyon.org.uk/ # v5
Link: https://lore.kernel.org/r/161789079281.6155.17141344853277186500.stgit@warthog.procyon.org.uk/ # v6

1 files changed, 23 insertions, 0 deletions

diff --git a/fs/netfs/read_helper.c b/fs/netfs/read_helper.c
index 799eee7f4ee6..6d6ed30f417e 100644
--- a/fs/netfs/read_helper.c
+++ b/fs/netfs/read_helper.c
@@ -56,6 +56,7 @@ static struct netfs_read_request *netfs_alloc_read_request(
 		refcount_set(&rreq->usage, 1);
 		__set_bit(NETFS_RREQ_IN_PROGRESS, &rreq->flags);
 		ops->init_rreq(rreq, file);
+		netfs_stat(&netfs_n_rh_rreq);
 	}
 
 	return rreq;
@@ -88,6 +89,7 @@ static void netfs_free_read_request(struct work_struct *work)
 		rreq->netfs_ops->cleanup(rreq->mapping, rreq->netfs_priv);
 	trace_netfs_rreq(rreq, netfs_rreq_trace_free);
 	kfree(rreq);
+	netfs_stat_d(&netfs_n_rh_rreq);
 }
 
 static void netfs_put_read_request(struct netfs_read_request *rreq, bool was_async)
@@ -117,6 +119,7 @@ static struct netfs_read_subrequest *netfs_alloc_subrequest(
 		refcount_set(&subreq->usage, 2);
 		subreq->rreq = rreq;
 		netfs_get_read_request(rreq);
+		netfs_stat(&netfs_n_rh_sreq);
 	}
 
 	return subreq;
@@ -134,6 +137,7 @@ static void __netfs_put_subrequest(struct netfs_read_subrequest *subreq,
 
 	trace_netfs_sreq(subreq, netfs_sreq_trace_free);
 	kfree(subreq);
+	netfs_stat_d(&netfs_n_rh_sreq);
 	netfs_put_read_request(rreq, was_async);
 }
 
@@ -156,6 +160,7 @@ static void netfs_clear_unread(struct netfs_read_subrequest *subreq)
 static void netfs_fill_with_zeroes(struct netfs_read_request *rreq,
 				   struct netfs_read_subrequest *subreq)
 {
+	netfs_stat(&netfs_n_rh_zero);
 	__set_bit(NETFS_SREQ_CLEAR_TAIL, &subreq->flags);
 	netfs_subreq_terminated(subreq, 0, false);
 }
@@ -179,6 +184,7 @@ static void netfs_fill_with_zeroes(struct netfs_read_request *rreq,
 static void netfs_read_from_server(struct netfs_read_request *rreq,
 				   struct netfs_read_subrequest *subreq)
 {
+	netfs_stat(&netfs_n_rh_download);
 	rreq->netfs_ops->issue_op(subreq);
 }
 
@@ -288,6 +294,7 @@ static void netfs_rreq_short_read(struct netfs_read_request *rreq,
 	__clear_bit(NETFS_SREQ_SHORT_READ, &subreq->flags);
 	__set_bit(NETFS_SREQ_SEEK_DATA_READ, &subreq->flags);
 
+	netfs_stat(&netfs_n_rh_short_read);
 	trace_netfs_sreq(subreq, netfs_sreq_trace_resubmit_short);
 
 	netfs_get_read_subrequest(subreq);
@@ -319,6 +326,7 @@ static bool netfs_rreq_perform_resubmissions(struct netfs_read_request *rreq)
 				break;
 			subreq->source = NETFS_DOWNLOAD_FROM_SERVER;
 			subreq->error = 0;
+			netfs_stat(&netfs_n_rh_download_instead);
 			trace_netfs_sreq(subreq, netfs_sreq_trace_download_instead);
 			netfs_get_read_subrequest(subreq);
 			atomic_inc(&rreq->nr_rd_ops);
@@ -414,6 +422,17 @@ void netfs_subreq_terminated(struct netfs_read_subrequest *subreq,
 	       subreq->debug_index, subreq->start, subreq->flags,
 	       transferred_or_error);
 
+	switch (subreq->source) {
+	case NETFS_READ_FROM_CACHE:
+		netfs_stat(&netfs_n_rh_read_done);
+		break;
+	case NETFS_DOWNLOAD_FROM_SERVER:
+		netfs_stat(&netfs_n_rh_download_done);
+		break;
+	default:
+		break;
+	}
+
 	if (IS_ERR_VALUE(transferred_or_error)) {
 		subreq->error = transferred_or_error;
 		goto failed;
@@ -470,8 +489,10 @@ incomplete:
 
 failed:
 	if (subreq->source == NETFS_READ_FROM_CACHE) {
+		netfs_stat(&netfs_n_rh_read_failed);
 		set_bit(NETFS_RREQ_INCOMPLETE_IO, &rreq->flags);
 	} else {
+		netfs_stat(&netfs_n_rh_download_failed);
 		set_bit(NETFS_RREQ_FAILED, &rreq->flags);
 		rreq->error = subreq->error;
 	}
@@ -653,6 +674,7 @@ void netfs_readahead(struct readahead_control *ractl,
 	rreq->start	= readahead_pos(ractl);
 	rreq->len	= readahead_length(ractl);
 
+	netfs_stat(&netfs_n_rh_readahead);
 	trace_netfs_read(rreq, readahead_pos(ractl), readahead_length(ractl),
 			 netfs_read_trace_readahead);
 
@@ -722,6 +744,7 @@ int netfs_readpage(struct file *file,
 	rreq->start	= page_index(page) * PAGE_SIZE;
 	rreq->len	= thp_size(page);
 
+	netfs_stat(&netfs_n_rh_readpage);
 	trace_netfs_read(rreq, rreq->start, rreq->len, netfs_read_trace_readpage);
 
 	netfs_get_read_request(rreq);