Unverified Commit 0cee64c5 authored by Jan Kara's avatar Jan Kara Committed by Christian Brauner
Browse files

writeback: Add tracepoint to track pending inode switches 



Add trace_inode_switch_wbs_queue tracepoint to allow insight into how
many inodes are queued to switch their bdi_writeback structure.

Acked-by: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent 9a6ebbdb

fs/fs-writeback.c

+2 −0
Original line number Diff line number Diff line
@@ -667,6 +667,7 @@ static void inode_switch_wbs(struct inode *inode, int new_wb_id) 


	isw->inodes[0] = inode;



	trace_inode_switch_wbs_queue(inode->i_wb, new_wb, 1);

	wb_queue_isw(new_wb, isw);

	return;
@@ -752,6 +753,7 @@ bool cleanup_offline_cgwb(struct bdi_writeback *wb) 
		return restart;

	}



	trace_inode_switch_wbs_queue(wb, new_wb, nr);

	wb_queue_isw(new_wb, isw);



	return restart;

include/trace/events/writeback.h

+29 −0
Original line number Diff line number Diff line
@@ -213,6 +213,35 @@ TRACE_EVENT(inode_foreign_history, 
	)

);



TRACE_EVENT(inode_switch_wbs_queue,



	TP_PROTO(struct bdi_writeback *old_wb, struct bdi_writeback *new_wb,

		 unsigned int count),



	TP_ARGS(old_wb, new_wb, count),



	TP_STRUCT__entry(

		__array(char,		name, 32)

		__field(ino_t,		old_cgroup_ino)

		__field(ino_t,		new_cgroup_ino)

		__field(unsigned int,	count)

	),



	TP_fast_assign(

		strscpy_pad(__entry->name, bdi_dev_name(old_wb->bdi), 32);

		__entry->old_cgroup_ino	= __trace_wb_assign_cgroup(old_wb);

		__entry->new_cgroup_ino	= __trace_wb_assign_cgroup(new_wb);

		__entry->count		= count;

	),



	TP_printk("bdi %s: old_cgroup_ino=%lu new_cgroup_ino=%lu count=%u",

		__entry->name,

		(unsigned long)__entry->old_cgroup_ino,

		(unsigned long)__entry->new_cgroup_ino,

		__entry->count

	)

);



TRACE_EVENT(inode_switch_wbs,



	TP_PROTO(struct inode *inode, struct bdi_writeback *old_wb,