Commit 368e2d09 authored by Dave Chinner's avatar Dave Chinner
Browse files

xfs: rework the perag trace points to be perag centric 



So that they all output the same information in the traces to make
debugging refcount issues easier.

This means that all the lookup/drop functions no longer need to use
the full memory barrier atomic operations (atomic*_return()) so
will have less overhead when tracing is off. The set/clear tag
tracepoints no longer abuse the reference count to pass the tag -
the tag being cleared is obvious from the _RET_IP_ that is recorded
in the trace point.

Signed-off-by: default avatarDave Chinner <dchinner@redhat.com>
Reviewed-by: default avatarAllison Henderson <allison.henderson@oracle.com>
Reviewed-by: default avatarDarrick J. Wong <djwong@kernel.org>
parent c4d5660a

fs/xfs/libxfs/xfs_ag.c

+9 −16
Original line number Diff line number Diff line
@@ -44,16 +44,15 @@ xfs_perag_get( 
	xfs_agnumber_t		agno)

{

	struct xfs_perag	*pag;

	int			ref = 0;



	rcu_read_lock();

	pag = radix_tree_lookup(&mp->m_perag_tree, agno);

	if (pag) {

		trace_xfs_perag_get(pag, _RET_IP_);

		ASSERT(atomic_read(&pag->pag_ref) >= 0);

		ref = atomic_inc_return(&pag->pag_ref);

		atomic_inc(&pag->pag_ref);

	}

	rcu_read_unlock();

	trace_xfs_perag_get(mp, agno, ref, _RET_IP_);

	return pag;

}
@@ -68,7 +67,6 @@ xfs_perag_get_tag( 
{

	struct xfs_perag	*pag;

	int			found;

	int			ref;



	rcu_read_lock();

	found = radix_tree_gang_lookup_tag(&mp->m_perag_tree,
@@ -77,9 +75,9 @@ xfs_perag_get_tag( 
		rcu_read_unlock();

		return NULL;

	}

	ref = atomic_inc_return(&pag->pag_ref);

	trace_xfs_perag_get_tag(pag, _RET_IP_);

	atomic_inc(&pag->pag_ref);

	rcu_read_unlock();

	trace_xfs_perag_get_tag(mp, pag->pag_agno, ref, _RET_IP_);

	return pag;

}
@@ -87,11 +85,9 @@ void 
xfs_perag_put(

	struct xfs_perag	*pag)

{

	int	ref;



	trace_xfs_perag_put(pag, _RET_IP_);

	ASSERT(atomic_read(&pag->pag_ref) > 0);

	ref = atomic_dec_return(&pag->pag_ref);

	trace_xfs_perag_put(pag->pag_mount, pag->pag_agno, ref, _RET_IP_);

	atomic_dec(&pag->pag_ref);

}



/*
@@ -110,8 +106,7 @@ xfs_perag_grab( 
	rcu_read_lock();

	pag = radix_tree_lookup(&mp->m_perag_tree, agno);

	if (pag) {

		trace_xfs_perag_grab(mp, pag->pag_agno,

				atomic_read(&pag->pag_active_ref), _RET_IP_);

		trace_xfs_perag_grab(pag, _RET_IP_);

		if (!atomic_inc_not_zero(&pag->pag_active_ref))

			pag = NULL;

	}
@@ -138,8 +133,7 @@ xfs_perag_grab_tag( 
		rcu_read_unlock();

		return NULL;

	}

	trace_xfs_perag_grab_tag(mp, pag->pag_agno,

			atomic_read(&pag->pag_active_ref), _RET_IP_);

	trace_xfs_perag_grab_tag(pag, _RET_IP_);

	if (!atomic_inc_not_zero(&pag->pag_active_ref))

		pag = NULL;

	rcu_read_unlock();
@@ -150,8 +144,7 @@ void 
xfs_perag_rele(

	struct xfs_perag	*pag)

{

	trace_xfs_perag_rele(pag->pag_mount, pag->pag_agno,

			atomic_read(&pag->pag_active_ref), _RET_IP_);

	trace_xfs_perag_rele(pag, _RET_IP_);

	if (atomic_dec_and_test(&pag->pag_active_ref))

		wake_up(&pag->pag_active_wq);

}

fs/xfs/xfs_icache.c

+2 −2
Original line number Diff line number Diff line
@@ -255,7 +255,7 @@ xfs_perag_set_inode_tag( 
		break;

	}



	trace_xfs_perag_set_inode_tag(mp, pag->pag_agno, tag, _RET_IP_);

	trace_xfs_perag_set_inode_tag(pag, _RET_IP_);

}



/* Clear a tag on both the AG incore inode tree and the AG radix tree. */
@@ -289,7 +289,7 @@ xfs_perag_clear_inode_tag( 
	radix_tree_tag_clear(&mp->m_perag_tree, pag->pag_agno, tag);

	spin_unlock(&mp->m_perag_lock);



	trace_xfs_perag_clear_inode_tag(mp, pag->pag_agno, tag, _RET_IP_);

	trace_xfs_perag_clear_inode_tag(pag, _RET_IP_);

}



/*

fs/xfs/xfs_trace.h

+11 −10
Original line number Diff line number Diff line
@@ -159,33 +159,34 @@ TRACE_EVENT(xlog_intent_recovery_failed, 
);



DECLARE_EVENT_CLASS(xfs_perag_class,

	TP_PROTO(struct xfs_mount *mp, xfs_agnumber_t agno, int refcount,

		 unsigned long caller_ip),

	TP_ARGS(mp, agno, refcount, caller_ip),

	TP_PROTO(struct xfs_perag *pag, unsigned long caller_ip),

	TP_ARGS(pag, caller_ip),

	TP_STRUCT__entry(

		__field(dev_t, dev)

		__field(xfs_agnumber_t, agno)

		__field(int, refcount)

		__field(int, active_refcount)

		__field(unsigned long, caller_ip)

	),

	TP_fast_assign(

		__entry->dev = mp->m_super->s_dev;

		__entry->agno = agno;

		__entry->refcount = refcount;

		__entry->dev = pag->pag_mount->m_super->s_dev;

		__entry->agno = pag->pag_agno;

		__entry->refcount = atomic_read(&pag->pag_ref);

		__entry->active_refcount = atomic_read(&pag->pag_active_ref);

		__entry->caller_ip = caller_ip;

	),

	TP_printk("dev %d:%d agno 0x%x refcount %d caller %pS",

	TP_printk("dev %d:%d agno 0x%x passive refs %d active refs %d caller %pS",

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

		  __entry->agno,

		  __entry->refcount,

		  __entry->active_refcount,

		  (char *)__entry->caller_ip)

);



#define DEFINE_PERAG_REF_EVENT(name)	\

DEFINE_EVENT(xfs_perag_class, name,	\

	TP_PROTO(struct xfs_mount *mp, xfs_agnumber_t agno, int refcount,	\

		 unsigned long caller_ip),					\

	TP_ARGS(mp, agno, refcount, caller_ip))

	TP_PROTO(struct xfs_perag *pag, unsigned long caller_ip), \

	TP_ARGS(pag, caller_ip))

DEFINE_PERAG_REF_EVENT(xfs_perag_get);

DEFINE_PERAG_REF_EVENT(xfs_perag_get_tag);

DEFINE_PERAG_REF_EVENT(xfs_perag_put);