Commit 504634f6 authored by Shaohua Li's avatar Shaohua Li
Browse files

md: add blktrace event for writes to superblock 



superblock write is an expensive operation. With raid5-cache, it can be called
regularly. Tracing to help performance debug.

Signed-off-by: default avatarShaohua Li <shli@fb.com>
Cc: NeilBrown <neilb@suse.com>
parent 578b54ad

drivers/md/md.c

+3 −0
Original line number Diff line number Diff line
@@ -64,6 +64,7 @@ 
#include <linux/raid/md_p.h>

#include <linux/raid/md_u.h>

#include <linux/slab.h>

#include <trace/events/block.h>

#include "md.h"

#include "bitmap.h"

#include "md-cluster.h"
@@ -2403,6 +2404,8 @@ repeat: 
	pr_debug("md: updating %s RAID superblock on device (in sync %d)\n",

		 mdname(mddev), mddev->in_sync);



	if (mddev->queue)

		blk_add_trace_msg(mddev->queue, "md md_update_sb");

	bitmap_update_sb(mddev->bitmap);

	rdev_for_each(rdev, mddev) {

		char b[BDEVNAME_SIZE];