drbd: gather detailed timing statistics for drbd_requests
Record (in jiffies) how much time a request spends in which stages.
Followup commits will use and present this additional timing information
so we can better locate and tackle the root causes of latency spikes,
or present the backlog for asynchronous replication.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 3ab7461..0baec7a 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -29,6 +29,7 @@
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
+#include <linux/jiffies.h>
#include <linux/drbd.h>
#include <asm/uaccess.h>
#include <asm/types.h>
@@ -264,7 +265,7 @@
/**
* _tl_restart() - Walks the transfer log, and applies an action to all requests
- * @device: DRBD device.
+ * @connection: DRBD connection to operate on.
* @what: The action/event to perform with all request objects
*
* @what might be one of CONNECTION_LOST_WHILE_PENDING, RESEND, FAIL_FROZEN_DISK_IO,
@@ -2228,7 +2229,7 @@
list_for_each_entry_safe(req, tmp, &writes, tl_requests) {
struct drbd_device *device = req->device;
struct bio *bio = req->master_bio;
- unsigned long start_time = req->start_time;
+ unsigned long start_jif = req->start_jif;
bool expected;
expected =
@@ -2263,7 +2264,7 @@
/* We are not just doing generic_make_request(),
* as we want to keep the start_time information. */
inc_ap_bio(device);
- __drbd_make_request(device, bio, start_time);
+ __drbd_make_request(device, bio, start_jif);
}
}