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Commit 343d9c28 authored by Theodore Ts'o's avatar Theodore Ts'o
Browse files

jbd2: add tracepoints which provide per-handle statistics 



Handles which stay open a long time are problematic when it comes time
to close down a transaction so it can be committed.  These tracepoints
will help us determine which ones are the problematic ones, and to
validate whether changes makes things better or worse.

Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent 078d5039

fs/jbd2/transaction.c

+26 −2
Original line number Diff line number Diff line
@@ -30,6 +30,8 @@ 
#include <linux/bug.h>

#include <linux/module.h>



#include <trace/events/jbd2.h>



static void __jbd2_journal_temp_unlink_buffer(struct journal_head *jh);

static void __jbd2_journal_unfile_buffer(struct journal_head *jh);
@@ -307,6 +309,8 @@ static int start_this_handle(journal_t *journal, handle_t *handle, 
	 */

	update_t_max_wait(transaction, ts);

	handle->h_transaction = transaction;

	handle->h_requested_credits = nblocks;

	handle->h_start_jiffies = jiffies;

	atomic_inc(&transaction->t_updates);

	atomic_inc(&transaction->t_handle_count);

	jbd_debug(4, "Handle %p given %d credits (total %d, free %d)\n",
@@ -353,7 +357,8 @@ static handle_t *new_handle(int nblocks) 
 * Return a pointer to a newly allocated handle, or an ERR_PTR() value

 * on failure.

 */

handle_t *jbd2__journal_start(journal_t *journal, int nblocks, gfp_t gfp_mask)

handle_t *jbd2__journal_start(journal_t *journal, int nblocks, gfp_t gfp_mask,

			      unsigned int type, unsigned int line_no)

{

	handle_t *handle = journal_current_handle();

	int err;
@@ -379,6 +384,11 @@ handle_t *jbd2__journal_start(journal_t *journal, int nblocks, gfp_t gfp_mask) 
		current->journal_info = NULL;

		handle = ERR_PTR(err);

	}

	handle->h_type = type;

	handle->h_line_no = line_no;

	trace_jbd2_handle_start(journal->j_fs_dev->bd_dev,

				handle->h_transaction->t_tid, type,

				line_no, nblocks);

	return handle;

}

EXPORT_SYMBOL(jbd2__journal_start);
@@ -386,7 +396,7 @@ EXPORT_SYMBOL(jbd2__journal_start); 


handle_t *jbd2_journal_start(journal_t *journal, int nblocks)

{

	return jbd2__journal_start(journal, nblocks, GFP_NOFS);

	return jbd2__journal_start(journal, nblocks, GFP_NOFS, 0, 0);

}

EXPORT_SYMBOL(jbd2_journal_start);
@@ -448,7 +458,14 @@ int jbd2_journal_extend(handle_t *handle, int nblocks) 
		goto unlock;

	}



	trace_jbd2_handle_extend(journal->j_fs_dev->bd_dev,

				 handle->h_transaction->t_tid,

				 handle->h_type, handle->h_line_no,

				 handle->h_buffer_credits,

				 nblocks);



	handle->h_buffer_credits += nblocks;

	handle->h_requested_credits += nblocks;

	atomic_add(nblocks, &transaction->t_outstanding_credits);

	result = 0;
@@ -1377,6 +1394,13 @@ int jbd2_journal_stop(handle_t *handle) 
	}



	jbd_debug(4, "Handle %p going down\n", handle);

	trace_jbd2_handle_stats(journal->j_fs_dev->bd_dev,

				handle->h_transaction->t_tid,

				handle->h_type, handle->h_line_no,

				jiffies - handle->h_start_jiffies,

				handle->h_sync, handle->h_requested_credits,

				(handle->h_requested_credits -

				 handle->h_buffer_credits));



	/*

	 * Implement synchronous transaction batching.  If the handle

include/linux/jbd2.h

+7 −1
Original line number Diff line number Diff line
@@ -400,6 +400,11 @@ struct jbd2_journal_handle 
	unsigned int	h_sync:		1;	/* sync-on-close */

	unsigned int	h_jdata:	1;	/* force data journaling */

	unsigned int	h_aborted:	1;	/* fatal error on handle */

	unsigned int	h_type:		8;	/* for handle statistics */

	unsigned int	h_line_no:	16;	/* for handle statistics */



	unsigned long		h_start_jiffies;

	unsigned int		h_requested_credits;



#ifdef CONFIG_DEBUG_LOCK_ALLOC

	struct lockdep_map	h_lockdep_map;
@@ -1071,7 +1076,8 @@ static inline handle_t *journal_current_handle(void) 
 */



extern handle_t *jbd2_journal_start(journal_t *, int nblocks);

extern handle_t *jbd2__journal_start(journal_t *, int nblocks, gfp_t gfp_mask);

extern handle_t *jbd2__journal_start(journal_t *, int nblocks, gfp_t gfp_mask,

				     unsigned int type, unsigned int line_no);

extern int	 jbd2_journal_restart(handle_t *, int nblocks);

extern int	 jbd2__journal_restart(handle_t *, int nblocks, gfp_t gfp_mask);

extern int	 jbd2_journal_extend (handle_t *, int nblocks);

include/trace/events/jbd2.h

+98 −0
Original line number Diff line number Diff line
@@ -132,6 +132,104 @@ TRACE_EVENT(jbd2_submit_inode_data, 
		  (unsigned long) __entry->ino)

);



TRACE_EVENT(jbd2_handle_start,

	TP_PROTO(dev_t dev, unsigned long tid, unsigned int type,

		 unsigned int line_no, int requested_blocks),



	TP_ARGS(dev, tid, type, line_no, requested_blocks),



	TP_STRUCT__entry(

		__field(		dev_t,	dev		)

		__field(	unsigned long,	tid		)

		__field(	 unsigned int,	type		)

		__field(	 unsigned int,	line_no		)

		__field(		  int,	requested_blocks)

	),



	TP_fast_assign(

		__entry->dev		  = dev;

		__entry->tid		  = tid;

		__entry->type		  = type;

		__entry->line_no	  = line_no;

		__entry->requested_blocks = requested_blocks;

	),



	TP_printk("dev %d,%d tid %lu type %u line_no %u "

		  "requested_blocks %d",

		  MAJOR(__entry->dev), MINOR(__entry->dev), __entry->tid,

		  __entry->type, __entry->line_no, __entry->requested_blocks)

);



TRACE_EVENT(jbd2_handle_extend,

	TP_PROTO(dev_t dev, unsigned long tid, unsigned int type,

		 unsigned int line_no, int buffer_credits,

		 int requested_blocks),



	TP_ARGS(dev, tid, type, line_no, buffer_credits, requested_blocks),



	TP_STRUCT__entry(

		__field(		dev_t,	dev		)

		__field(	unsigned long,	tid		)

		__field(	 unsigned int,	type		)

		__field(	 unsigned int,	line_no		)

		__field(		  int,	buffer_credits  )

		__field(		  int,	requested_blocks)

	),



	TP_fast_assign(

		__entry->dev		  = dev;

		__entry->tid		  = tid;

		__entry->type		  = type;

		__entry->line_no	  = line_no;

		__entry->buffer_credits   = buffer_credits;

		__entry->requested_blocks = requested_blocks;

	),



	TP_printk("dev %d,%d tid %lu type %u line_no %u "

		  "buffer_credits %d requested_blocks %d",

		  MAJOR(__entry->dev), MINOR(__entry->dev), __entry->tid,

		  __entry->type, __entry->line_no, __entry->buffer_credits,

		  __entry->requested_blocks)

);



TRACE_EVENT(jbd2_handle_stats,

	TP_PROTO(dev_t dev, unsigned long tid, unsigned int type,

		 unsigned int line_no, int interval, int sync,

		 int requested_blocks, int dirtied_blocks),



	TP_ARGS(dev, tid, type, line_no, interval, sync,

		requested_blocks, dirtied_blocks),



	TP_STRUCT__entry(

		__field(		dev_t,	dev		)

		__field(	unsigned long,	tid		)

		__field(	 unsigned int,	type		)

		__field(	 unsigned int,	line_no		)

		__field(		  int,	interval	)

		__field(		  int,	sync		)

		__field(		  int,	requested_blocks)

		__field(		  int,	dirtied_blocks	)

	),



	TP_fast_assign(

		__entry->dev		  = dev;

		__entry->tid		  = tid;

		__entry->type		  = type;

		__entry->line_no	  = line_no;

		__entry->interval	  = interval;

		__entry->sync		  = sync;

		__entry->requested_blocks = requested_blocks;

		__entry->dirtied_blocks	  = dirtied_blocks;

	),



	TP_printk("dev %d,%d tid %lu type %u line_no %u interval %d "

		  "sync %d requested_blocks %d dirtied_blocks %d",

		  MAJOR(__entry->dev), MINOR(__entry->dev), __entry->tid,

		  __entry->type, __entry->line_no, __entry->interval,

		  __entry->sync, __entry->requested_blocks,

		  __entry->dirtied_blocks)

);



TRACE_EVENT(jbd2_run_stats,

	TP_PROTO(dev_t dev, unsigned long tid,

		 struct transaction_run_stats_s *stats),