Commit 9fb0a7da authored by Tejun Heo's avatar Tejun Heo Committed by Jens Axboe
Browse files

writeback: add more tracepoints 



Add tracepoints for page dirtying, writeback_single_inode start, inode
dirtying and writeback.  For the latter two inode events, a pair of
events are defined to denote start and end of the operations (the
starting one has _start suffix and the one w/o suffix happens after
the operation is complete).  These inode ops are FS specific and can
be non-trivial and having enclosing tracepoints is useful for external
tracers.

This is part of tracepoint additions to improve visiblity into
dirtying / writeback operations for io tracer and userland.

v2: writeback_dirty_inode[_start] TPs may be called for files on
    pseudo FSes w/ unregistered bdi.  Check whether bdi->dev is %NULL
    before dereferencing.

v3: buffer dirtying moved to a block TP.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 5305cb83

fs/fs-writeback.c

+14 −2
Original line number Diff line number Diff line
@@ -318,8 +318,14 @@ static void queue_io(struct bdi_writeback *wb, struct wb_writeback_work *work) 


static int write_inode(struct inode *inode, struct writeback_control *wbc)

{

	if (inode->i_sb->s_op->write_inode && !is_bad_inode(inode))

		return inode->i_sb->s_op->write_inode(inode, wbc);

	int ret;



	if (inode->i_sb->s_op->write_inode && !is_bad_inode(inode)) {

		trace_writeback_write_inode_start(inode, wbc);

		ret = inode->i_sb->s_op->write_inode(inode, wbc);

		trace_writeback_write_inode(inode, wbc);

		return ret;

	}

	return 0;

}
@@ -450,6 +456,8 @@ __writeback_single_inode(struct inode *inode, struct writeback_control *wbc) 


	WARN_ON(!(inode->i_state & I_SYNC));



	trace_writeback_single_inode_start(inode, wbc, nr_to_write);



	ret = do_writepages(mapping, wbc);



	/*
@@ -1150,8 +1158,12 @@ void __mark_inode_dirty(struct inode *inode, int flags) 
	 * dirty the inode itself

	 */

	if (flags & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) {

		trace_writeback_dirty_inode_start(inode, flags);



		if (sb->s_op->dirty_inode)

			sb->s_op->dirty_inode(inode, flags);



		trace_writeback_dirty_inode(inode, flags);

	}



	/*

include/trace/events/writeback.h

+116 −0
Original line number Diff line number Diff line
@@ -32,6 +32,115 @@ 


struct wb_writeback_work;



TRACE_EVENT(writeback_dirty_page,



	TP_PROTO(struct page *page, struct address_space *mapping),



	TP_ARGS(page, mapping),



	TP_STRUCT__entry (

		__array(char, name, 32)

		__field(unsigned long, ino)

		__field(pgoff_t, index)

	),



	TP_fast_assign(

		strncpy(__entry->name,

			mapping ? dev_name(mapping->backing_dev_info->dev) : "(unknown)", 32);

		__entry->ino = mapping ? mapping->host->i_ino : 0;

		__entry->index = page->index;

	),



	TP_printk("bdi %s: ino=%lu index=%lu",

		__entry->name,

		__entry->ino,

		__entry->index

	)

);



DECLARE_EVENT_CLASS(writeback_dirty_inode_template,



	TP_PROTO(struct inode *inode, int flags),



	TP_ARGS(inode, flags),



	TP_STRUCT__entry (

		__array(char, name, 32)

		__field(unsigned long, ino)

		__field(unsigned long, flags)

	),



	TP_fast_assign(

		struct backing_dev_info *bdi = inode->i_mapping->backing_dev_info;



		/* may be called for files on pseudo FSes w/ unregistered bdi */

		strncpy(__entry->name,

			bdi->dev ? dev_name(bdi->dev) : "(unknown)", 32);

		__entry->ino		= inode->i_ino;

		__entry->flags		= flags;

	),



	TP_printk("bdi %s: ino=%lu flags=%s",

		__entry->name,

		__entry->ino,

		show_inode_state(__entry->flags)

	)

);



DEFINE_EVENT(writeback_dirty_inode_template, writeback_dirty_inode_start,



	TP_PROTO(struct inode *inode, int flags),



	TP_ARGS(inode, flags)

);



DEFINE_EVENT(writeback_dirty_inode_template, writeback_dirty_inode,



	TP_PROTO(struct inode *inode, int flags),



	TP_ARGS(inode, flags)

);



DECLARE_EVENT_CLASS(writeback_write_inode_template,



	TP_PROTO(struct inode *inode, struct writeback_control *wbc),



	TP_ARGS(inode, wbc),



	TP_STRUCT__entry (

		__array(char, name, 32)

		__field(unsigned long, ino)

		__field(int, sync_mode)

	),



	TP_fast_assign(

		strncpy(__entry->name,

			dev_name(inode->i_mapping->backing_dev_info->dev), 32);

		__entry->ino		= inode->i_ino;

		__entry->sync_mode	= wbc->sync_mode;

	),



	TP_printk("bdi %s: ino=%lu sync_mode=%d",

		__entry->name,

		__entry->ino,

		__entry->sync_mode

	)

);



DEFINE_EVENT(writeback_write_inode_template, writeback_write_inode_start,



	TP_PROTO(struct inode *inode, struct writeback_control *wbc),



	TP_ARGS(inode, wbc)

);



DEFINE_EVENT(writeback_write_inode_template, writeback_write_inode,



	TP_PROTO(struct inode *inode, struct writeback_control *wbc),



	TP_ARGS(inode, wbc)

);



DECLARE_EVENT_CLASS(writeback_work_class,

	TP_PROTO(struct backing_dev_info *bdi, struct wb_writeback_work *work),

	TP_ARGS(bdi, work),
@@ -479,6 +588,13 @@ DECLARE_EVENT_CLASS(writeback_single_inode_template, 
	)

);



DEFINE_EVENT(writeback_single_inode_template, writeback_single_inode_start,

	TP_PROTO(struct inode *inode,

		 struct writeback_control *wbc,

		 unsigned long nr_to_write),

	TP_ARGS(inode, wbc, nr_to_write)

);



DEFINE_EVENT(writeback_single_inode_template, writeback_single_inode,

	TP_PROTO(struct inode *inode,

		 struct writeback_control *wbc,

mm/page-writeback.c

+2 −0
Original line number Diff line number Diff line
@@ -1982,6 +1982,8 @@ int __set_page_dirty_no_writeback(struct page *page) 
 */

void account_page_dirtied(struct page *page, struct address_space *mapping)

{

	trace_writeback_dirty_page(page, mapping);



	if (mapping_cap_account_dirty(mapping)) {

		__inc_zone_page_state(page, NR_FILE_DIRTY);

		__inc_zone_page_state(page, NR_DIRTIED);

CRA Git | Maintained and supported by SUSTech CRA and CCSE