[PATCH v2 4/8] ceph: add global write latency metric support

[xiubli@redhat.com]

From: Xiubo Li <xiubli@redhat.com>

item          total       sum_lat(us)     avg_lat(us)
-----------------------------------------------------
write         222         5287750000      23818693

Fixes: https://tracker.ceph.com/issues/43215
Signed-off-by: Xiubo Li <xiubli@redhat.com>
---
 fs/ceph/addr.c                  | 23 +++++++++++++++++++++--
 fs/ceph/debugfs.c               |  8 ++++++++
 fs/ceph/file.c                  | 12 ++++++++++--
 fs/ceph/mds_client.c            | 20 ++++++++++++++++++++
 fs/ceph/mds_client.h            |  6 ++++++
 include/linux/ceph/osd_client.h |  3 ++-
 net/ceph/osd_client.c           |  9 ++++++++-
 7 files changed, 75 insertions(+), 6 deletions(-)

diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index 2c51da3515a0..5337202530ec 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -598,12 +598,15 @@ static int writepage_nounlock(struct page *page, struct writeback_control *wbc)
 	loff_t page_off = page_offset(page);
 	int err, len = PAGE_SIZE;
 	struct ceph_writeback_ctl ceph_wbc;
+	struct ceph_client_metric *metric;
+	s64 latency;
 
 	dout("writepage %p idx %lu\n", page, page->index);
 
 	inode = page->mapping->host;
 	ci = ceph_inode(inode);
 	fsc = ceph_inode_to_client(inode);
+	metric = &fsc->mdsc->metric;
 
 	/* verify this is a writeable snap context */
 	snapc = page_snap_context(page);
@@ -645,7 +648,11 @@ static int writepage_nounlock(struct page *page, struct writeback_control *wbc)
 				   &ci->i_layout, snapc, page_off, len,
 				   ceph_wbc.truncate_seq,
 				   ceph_wbc.truncate_size,
-				   &inode->i_mtime, &page, 1);
+				   &inode->i_mtime, &page, 1,
+				   &latency);
+	if (latency)
+		ceph_mdsc_update_write_latency(metric, latency);
+
 	if (err < 0) {
 		struct writeback_control tmp_wbc;
 		if (!wbc)
@@ -707,6 +714,8 @@ static void writepages_finish(struct ceph_osd_request *req)
 {
 	struct inode *inode = req->r_inode;
 	struct ceph_inode_info *ci = ceph_inode(inode);
+	struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
+	struct ceph_client_metric *metric = &fsc->mdsc->metric;
 	struct ceph_osd_data *osd_data;
 	struct page *page;
 	int num_pages, total_pages = 0;
@@ -714,7 +723,6 @@ static void writepages_finish(struct ceph_osd_request *req)
 	int rc = req->r_result;
 	struct ceph_snap_context *snapc = req->r_snapc;
 	struct address_space *mapping = inode->i_mapping;
-	struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
 	bool remove_page;
 
 	dout("writepages_finish %p rc %d\n", inode, rc);
@@ -783,6 +791,11 @@ static void writepages_finish(struct ceph_osd_request *req)
 			     ceph_sb_to_client(inode->i_sb)->wb_pagevec_pool);
 	else
 		kfree(osd_data->pages);
+
+	if (!rc || rc == -ENOENT) {
+		s64 latency = jiffies - req->r_start_stamp;
+		ceph_mdsc_update_write_latency(metric, latency);
+	}
 	ceph_osdc_put_request(req);
 }
 
@@ -1675,6 +1688,7 @@ int ceph_uninline_data(struct file *filp, struct page *locked_page)
 	struct inode *inode = file_inode(filp);
 	struct ceph_inode_info *ci = ceph_inode(inode);
 	struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
+	struct ceph_client_metric *metric = &fsc->mdsc->metric;
 	struct ceph_osd_request *req;
 	struct page *page = NULL;
 	u64 len, inline_version;
@@ -1785,6 +1799,11 @@ int ceph_uninline_data(struct file *filp, struct page *locked_page)
 	err = ceph_osdc_start_request(&fsc->client->osdc, req, false);
 	if (!err)
 		err = ceph_osdc_wait_request(&fsc->client->osdc, req);
+
+	if (!err || err == -ETIMEDOUT) {
+		s64 latency = jiffies - req->r_start_stamp;
+		ceph_mdsc_update_write_latency(metric, latency);
+	}
 out_put:
 	ceph_osdc_put_request(req);
 	if (err == -ECANCELED)
diff --git a/fs/ceph/debugfs.c b/fs/ceph/debugfs.c
index 8200bf025ccd..3fdb15af0a83 100644
--- a/fs/ceph/debugfs.c
+++ b/fs/ceph/debugfs.c
@@ -142,6 +142,14 @@ static int metric_show(struct seq_file *s, void *p)
 	seq_printf(s, "%-14s%-12lld%-16lld%lld\n", "read",
 		   total, sum / NSEC_PER_USEC, avg / NSEC_PER_USEC);
 
+	spin_lock(&mdsc->metric.write_lock);
+	total = atomic64_read(&mdsc->metric.total_writes),
+	sum = timespec64_to_ns(&mdsc->metric.write_latency_sum);
+	spin_unlock(&mdsc->metric.write_lock);
+	avg = total ? sum / total : 0;
+	seq_printf(s, "%-14s%-12lld%-16lld%lld\n", "write",
+		   total, sum / NSEC_PER_USEC, avg / NSEC_PER_USEC);
+
 	seq_printf(s, "\n");
 	seq_printf(s, "item          total           miss            hit\n");
 	seq_printf(s, "-------------------------------------------------\n");
diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 84c9de9da022..f5754acac3b9 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -1054,9 +1054,12 @@ ceph_direct_read_write(struct kiocb *iocb, struct iov_iter *iter,
 		if (!ret)
 			ret = ceph_osdc_wait_request(&fsc->client->osdc, req);
 
-		if ((ret > 0 || ret == -ETIMEDOUT) && !write) {
+		if (ret > 0 || ret == -ETIMEDOUT) {
 			s64 latency = jiffies - req->r_start_stamp;
-			ceph_mdsc_update_read_latency(metric, latency);
+			if (write)
+				ceph_mdsc_update_write_latency(metric, latency);
+			else
+				ceph_mdsc_update_read_latency(metric, latency);
 		}
 
 		size = i_size_read(inode);
@@ -1145,6 +1148,7 @@ ceph_sync_write(struct kiocb *iocb, struct iov_iter *from, loff_t pos,
 	struct inode *inode = file_inode(file);
 	struct ceph_inode_info *ci = ceph_inode(inode);
 	struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
+	struct ceph_client_metric *metric = &fsc->mdsc->metric;
 	struct ceph_vino vino;
 	struct ceph_osd_request *req;
 	struct page **pages;
@@ -1230,6 +1234,10 @@ ceph_sync_write(struct kiocb *iocb, struct iov_iter *from, loff_t pos,
 		if (!ret)
 			ret = ceph_osdc_wait_request(&fsc->client->osdc, req);
 
+		if (!ret || ret == -ETIMEDOUT) {
+			s64 latency = jiffies - req->r_start_stamp;
+			ceph_mdsc_update_write_latency(metric, latency);
+		}
 out:
 		ceph_osdc_put_request(req);
 		if (ret != 0) {
diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index d36464766e2c..865ff33aac0b 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -4111,6 +4111,22 @@ void ceph_mdsc_update_read_latency(struct ceph_client_metric *m,
 	spin_unlock(&m->read_lock);
 }
 
+void ceph_mdsc_update_write_latency(struct ceph_client_metric *m,
+				    s64 latency)
+{
+	struct timespec64 ts;
+
+	if (!m)
+		return;
+
+	jiffies_to_timespec64(latency, &ts);
+
+	spin_lock(&m->write_lock);
+	atomic64_inc(&m->total_writes);
+	m->write_latency_sum = timespec64_add(m->write_latency_sum, ts);
+	spin_unlock(&m->write_lock);
+}
+
 /*
  * delayed work -- periodically trim expired leases, renew caps with mds
  */
@@ -4211,6 +4227,10 @@ static int ceph_mdsc_metric_init(struct ceph_client_metric *metric)
 	memset(&metric->read_latency_sum, 0, sizeof(struct timespec64));
 	atomic64_set(&metric->total_reads, 0);
 
+	spin_lock_init(&metric->write_lock);
+	memset(&metric->write_latency_sum, 0, sizeof(struct timespec64));
+	atomic64_set(&metric->total_writes, 0);
+
 	return 0;
 }
 
diff --git a/fs/ceph/mds_client.h b/fs/ceph/mds_client.h
index fb8412a1169b..1c8c446fb7bb 100644
--- a/fs/ceph/mds_client.h
+++ b/fs/ceph/mds_client.h
@@ -370,6 +370,10 @@ struct ceph_client_metric {
 	spinlock_t              read_lock;
 	atomic64_t		total_reads;
 	struct timespec64	read_latency_sum;
+
+	spinlock_t              write_lock;
+	atomic64_t		total_writes;
+	struct timespec64	write_latency_sum;
 };
 
 /*
@@ -556,4 +560,6 @@ extern int ceph_trim_caps(struct ceph_mds_client *mdsc,
 
 extern void ceph_mdsc_update_read_latency(struct ceph_client_metric *m,
 					  s64 latency);
+extern void ceph_mdsc_update_write_latency(struct ceph_client_metric *m,
+					   s64 latency);
 #endif
diff --git a/include/linux/ceph/osd_client.h b/include/linux/ceph/osd_client.h
index 8a7acd95f883..9d16c9cb1d69 100644
--- a/include/linux/ceph/osd_client.h
+++ b/include/linux/ceph/osd_client.h
@@ -524,7 +524,8 @@ extern int ceph_osdc_writepages(struct ceph_osd_client *osdc,
 				u64 off, u64 len,
 				u32 truncate_seq, u64 truncate_size,
 				struct timespec64 *mtime,
-				struct page **pages, int nr_pages);
+				struct page **pages, int nr_pages,
+				s64 *latency);
 
 int ceph_osdc_copy_from(struct ceph_osd_client *osdc,
 			u64 src_snapid, u64 src_version,
diff --git a/net/ceph/osd_client.c b/net/ceph/osd_client.c
index 547946d0c5d6..09632d79cd9a 100644
--- a/net/ceph/osd_client.c
+++ b/net/ceph/osd_client.c
@@ -5285,12 +5285,16 @@ int ceph_osdc_writepages(struct ceph_osd_client *osdc, struct ceph_vino vino,
 			 u64 off, u64 len,
 			 u32 truncate_seq, u64 truncate_size,
 			 struct timespec64 *mtime,
-			 struct page **pages, int num_pages)
+			 struct page **pages, int num_pages,
+			 s64 *latency)
 {
 	struct ceph_osd_request *req;
 	int rc = 0;
 	int page_align = off & ~PAGE_MASK;
 
+	if (latency)
+		*latency = 0;
+
 	req = ceph_osdc_new_request(osdc, layout, vino, off, &len, 0, 1,
 				    CEPH_OSD_OP_WRITE, CEPH_OSD_FLAG_WRITE,
 				    snapc, truncate_seq, truncate_size,
@@ -5308,6 +5312,9 @@ int ceph_osdc_writepages(struct ceph_osd_client *osdc, struct ceph_vino vino,
 	if (!rc)
 		rc = ceph_osdc_wait_request(osdc, req);
 
+	if (latency && (rc > 0 || rc == -ETIMEDOUT))
+		*latency = jiffies - req->r_start_stamp;
+
 	ceph_osdc_put_request(req);
 	if (rc == 0)
 		rc = len;
-- 
2.21.0