[ipfire-2.x.git] / src / patches / suse-2.6.27.25 / patches.fixes / xfs-kern_32215a_Clean-up-dquot-pincount-code.patch

Date: Fri, Sep 26 2008 15:20:10 +1000
From: Peter Leckie <pleckie@sgi.com>
References: SGI:PV986789 bnc#482148
Subject: Clean up dquot pincount code
Patch-mainline: 2.6.28

Clean up dquot pincount code.

This is a code cleanup and optimization that removes a per mount point
spinlock from the quota code and cleans up the code.

The patch changes the pincount from being an int protected by a spinlock
to an atomic_t allowing the pincount to be manipulated without holding
the spinlock.

This cleanup also protects against random wakup's of both the aild and
xfssyncd by reevaluating the pincount after been woken. Two latter patches
will address the Spurious wakeups.

Signed-off-by: Peter Leckie <pleckie@sgi.com>
Acked-by: Jan Kara <jack@suse.cz>

Index: linux/fs/xfs/quota/xfs_dquot_item.c
===================================================================
--- linux.orig/fs/xfs/quota/xfs_dquot_item.c	2008-10-09 17:13:53.000000000 -0500
+++ linux/fs/xfs/quota/xfs_dquot_item.c	2009-03-09 10:24:24.000000000 -0500
@@ -88,25 +88,23 @@ xfs_qm_dquot_logitem_format(
 
 /*
  * Increment the pin count of the given dquot.
- * This value is protected by pinlock spinlock in the xQM structure.
  */
 STATIC void
 xfs_qm_dquot_logitem_pin(
 	xfs_dq_logitem_t *logitem)
 {
-	xfs_dquot_t *dqp;
+	xfs_dquot_t *dqp = logitem->qli_dquot;
 
-	dqp = logitem->qli_dquot;
 	ASSERT(XFS_DQ_IS_LOCKED(dqp));
-	spin_lock(&(XFS_DQ_TO_QINF(dqp)->qi_pinlock));
-	dqp->q_pincount++;
-	spin_unlock(&(XFS_DQ_TO_QINF(dqp)->qi_pinlock));
+	atomic_inc(&dqp->q_pincount);
+
 }
 
 /*
  * Decrement the pin count of the given dquot, and wake up
  * anyone in xfs_dqwait_unpin() if the count goes to 0.	 The
- * dquot must have been previously pinned with a call to xfs_dqpin().
+ * dquot must have been previously pinned with a call to
+ * xfs_qm_dquot_logitem_pin().
  */
 /* ARGSUSED */
 STATIC void
@@ -114,16 +112,12 @@ xfs_qm_dquot_logitem_unpin(
 	xfs_dq_logitem_t *logitem,
 	int		  stale)
 {
-	xfs_dquot_t *dqp;
+xfs_dquot_t *dqp = logitem->qli_dquot;
+
+	ASSERT(atomic_read(&dqp->q_pincount) > 0);
+	if (atomic_dec_and_test(&dqp->q_pincount))
+		wake_up(&dqp->q_pinwait);
 
-	dqp = logitem->qli_dquot;
-	ASSERT(dqp->q_pincount > 0);
-	spin_lock(&(XFS_DQ_TO_QINF(dqp)->qi_pinlock));
-	dqp->q_pincount--;
-	if (dqp->q_pincount == 0) {
-		sv_broadcast(&dqp->q_pinwait);
-	}
-	spin_unlock(&(XFS_DQ_TO_QINF(dqp)->qi_pinlock));
 }
 
 /* ARGSUSED */
@@ -193,7 +187,7 @@ xfs_qm_dqunpin_wait(
 	xfs_dquot_t	*dqp)
 {
 	ASSERT(XFS_DQ_IS_LOCKED(dqp));
-	if (dqp->q_pincount == 0) {
+	if (atomic_read(&dqp->q_pincount) == 0) {
 		return;
 	}
 
@@ -201,13 +195,7 @@ xfs_qm_dqunpin_wait(
 	 * Give the log a push so we don't wait here too long.
 	 */
 	xfs_log_force(dqp->q_mount, (xfs_lsn_t)0, XFS_LOG_FORCE);
-	spin_lock(&(XFS_DQ_TO_QINF(dqp)->qi_pinlock));
-	if (dqp->q_pincount == 0) {
-		spin_unlock(&(XFS_DQ_TO_QINF(dqp)->qi_pinlock));
-		return;
-	}
-	sv_wait(&(dqp->q_pinwait), PINOD,
-		&(XFS_DQ_TO_QINF(dqp)->qi_pinlock), s);
+	wait_event(dqp->q_pinwait, (atomic_read(&dqp->q_pincount) == 0));
 }
 
 /*
@@ -310,7 +298,7 @@ xfs_qm_dquot_logitem_trylock(
 	uint			retval;
 
 	dqp = qip->qli_dquot;
-	if (dqp->q_pincount > 0)
+	if (atomic_read(&dqp->q_pincount) > 0)
 		return (XFS_ITEM_PINNED);
 
 	if (! xfs_qm_dqlock_nowait(dqp))
Index: linux/fs/xfs/quota/xfs_dquot.h
===================================================================
--- linux.orig/fs/xfs/quota/xfs_dquot.h	2008-10-09 17:13:53.000000000 -0500
+++ linux/fs/xfs/quota/xfs_dquot.h	2009-03-09 10:36:25.000000000 -0500
@@ -83,8 +83,9 @@ typedef struct xfs_dquot {
 	xfs_qcnt_t	 q_res_rtbcount;/* total realtime blks used+reserved */
 	mutex_t		 q_qlock;	/* quota lock */
 	struct completion q_flush;	/* flush completion queue */
-	uint		 q_pincount;	/* pin count for this dquot */
-	sv_t		 q_pinwait;	/* sync var for pinning */
+	atomic_t          q_pincount;   /* dquot pin count */
+	wait_queue_head_t q_pinwait;    /* dquot pinning wait queue */
+
 #ifdef XFS_DQUOT_TRACE
 	struct ktrace	*q_trace;	/* trace header structure */
 #endif
Index: linux/fs/xfs/quota/xfs_dquot.c
===================================================================
--- linux.orig/fs/xfs/quota/xfs_dquot.c	2008-10-09 17:13:53.000000000 -0500
+++ linux/fs/xfs/quota/xfs_dquot.c	2009-03-09 10:38:06.000000000 -0500
@@ -101,7 +101,7 @@ xfs_qm_dqinit(
 	if (brandnewdquot) {
 		dqp->dq_flnext = dqp->dq_flprev = dqp;
 		mutex_init(&dqp->q_qlock);
-		sv_init(&dqp->q_pinwait, SV_DEFAULT, "pdq");
+		init_waitqueue_head(&dqp->q_pinwait);
 
 		/*
 		 * Because we want to use a counting completion, complete
@@ -131,7 +131,7 @@ xfs_qm_dqinit(
 		 dqp->q_res_bcount = 0;
 		 dqp->q_res_icount = 0;
 		 dqp->q_res_rtbcount = 0;
-		 dqp->q_pincount = 0;
+		 atomic_set(&dqp->q_pincount, 0);
 		 dqp->q_hash = NULL;
 		 ASSERT(dqp->dq_flnext == dqp->dq_flprev);
 
@@ -1489,7 +1489,7 @@ xfs_qm_dqpurge(
 				"xfs_qm_dqpurge: dquot %p flush failed", dqp);
 		xfs_dqflock(dqp);
 	}
-	ASSERT(dqp->q_pincount == 0);
+	ASSERT(atomic_read(&dqp->q_pincount) == 0);
 	ASSERT(XFS_FORCED_SHUTDOWN(mp) ||
 	       !(dqp->q_logitem.qli_item.li_flags & XFS_LI_IN_AIL));
 
Index: linux/fs/xfs/quota/xfs_qm.h
===================================================================
--- linux.orig/fs/xfs/quota/xfs_qm.h	2008-10-09 17:13:53.000000000 -0500
+++ linux/fs/xfs/quota/xfs_qm.h	2009-03-09 10:11:15.000000000 -0500
@@ -106,7 +106,6 @@ typedef struct xfs_qm {
 typedef struct xfs_quotainfo {
 	xfs_inode_t	*qi_uquotaip;	 /* user quota inode */
 	xfs_inode_t	*qi_gquotaip;	 /* group quota inode */
-	spinlock_t	 qi_pinlock;	 /* dquot pinning lock */
 	xfs_dqlist_t	 qi_dqlist;	 /* all dquots in filesys */
 	int		 qi_dqreclaims;	 /* a change here indicates
 					    a removal in the dqlist */
Index: linux/fs/xfs/quota/xfs_qm.c
===================================================================
--- linux.orig/fs/xfs/quota/xfs_qm.c	2008-10-09 17:13:53.000000000 -0500
+++ linux/fs/xfs/quota/xfs_qm.c	2009-03-09 10:12:12.000000000 -0500
@@ -1137,7 +1137,6 @@ xfs_qm_init_quotainfo(
 		return error;
 	}
 
-	spin_lock_init(&qinf->qi_pinlock);
 	xfs_qm_list_init(&qinf->qi_dqlist, "mpdqlist", 0);
 	qinf->qi_dqreclaims = 0;
 
@@ -1234,7 +1233,6 @@ xfs_qm_destroy_quotainfo(
 	 */
 	xfs_qm_rele_quotafs_ref(mp);
 
-	spinlock_destroy(&qi->qi_pinlock);
 	xfs_qm_list_destroy(&qi->qi_dqlist);
 
 	if (qi->qi_uquotaip) {
Commit	Line	Data
00e5a55c BS	1	Date: Fri, Sep 26 2008 15:20:10 +1000
	2	From: Peter Leckie <pleckie@sgi.com>
	3	References: SGI:PV986789 bnc#482148
	4	Subject: Clean up dquot pincount code
	5	Patch-mainline: 2.6.28
	6
	7	Clean up dquot pincount code.
	8
	9	This is a code cleanup and optimization that removes a per mount point
	10	spinlock from the quota code and cleans up the code.
	11
	12	The patch changes the pincount from being an int protected by a spinlock
	13	to an atomic_t allowing the pincount to be manipulated without holding
	14	the spinlock.
	15
	16	This cleanup also protects against random wakup's of both the aild and
	17	xfssyncd by reevaluating the pincount after been woken. Two latter patches
	18	will address the Spurious wakeups.
	19
	20	Signed-off-by: Peter Leckie <pleckie@sgi.com>
	21	Acked-by: Jan Kara <jack@suse.cz>
	22
	23	Index: linux/fs/xfs/quota/xfs_dquot_item.c
	24	===================================================================
	25	--- linux.orig/fs/xfs/quota/xfs_dquot_item.c 2008-10-09 17:13:53.000000000 -0500
	26	+++ linux/fs/xfs/quota/xfs_dquot_item.c 2009-03-09 10:24:24.000000000 -0500
	27	@@ -88,25 +88,23 @@ xfs_qm_dquot_logitem_format(
	28
	29	/*
	30	* Increment the pin count of the given dquot.
	31	- * This value is protected by pinlock spinlock in the xQM structure.
	32	*/
	33	STATIC void
	34	xfs_qm_dquot_logitem_pin(
	35	xfs_dq_logitem_t *logitem)
	36	{
	37	- xfs_dquot_t *dqp;
	38	+ xfs_dquot_t *dqp = logitem->qli_dquot;
	39
	40	- dqp = logitem->qli_dquot;
	41	ASSERT(XFS_DQ_IS_LOCKED(dqp));
	42	- spin_lock(&(XFS_DQ_TO_QINF(dqp)->qi_pinlock));
	43	- dqp->q_pincount++;
	44	- spin_unlock(&(XFS_DQ_TO_QINF(dqp)->qi_pinlock));
	45	+ atomic_inc(&dqp->q_pincount);
	46	+
	47	}
	48
	49	/*
	50	* Decrement the pin count of the given dquot, and wake up
	51	* anyone in xfs_dqwait_unpin() if the count goes to 0. The
	52	- * dquot must have been previously pinned with a call to xfs_dqpin().
	53	+ * dquot must have been previously pinned with a call to
	54	+ * xfs_qm_dquot_logitem_pin().
	55	*/
	56	/* ARGSUSED */
	57	STATIC void
	58	@@ -114,16 +112,12 @@ xfs_qm_dquot_logitem_unpin(
	59	xfs_dq_logitem_t *logitem,
	60	int stale)
	61	{
	62	- xfs_dquot_t *dqp;
	63	+xfs_dquot_t *dqp = logitem->qli_dquot;
	64	+
65	+ ASSERT(atomic_read(&dqp->q_pincount) > 0);
66	+ if (atomic_dec_and_test(&dqp->q_pincount))
67	+ wake_up(&dqp->q_pinwait);
68
69	- dqp = logitem->qli_dquot;
70	- ASSERT(dqp->q_pincount > 0);
71	- spin_lock(&(XFS_DQ_TO_QINF(dqp)->qi_pinlock));
72	- dqp->q_pincount--;
73	- if (dqp->q_pincount == 0) {
74	- sv_broadcast(&dqp->q_pinwait);
75	- }
76	- spin_unlock(&(XFS_DQ_TO_QINF(dqp)->qi_pinlock));
77	}
78
79	/* ARGSUSED */
80	@@ -193,7 +187,7 @@ xfs_qm_dqunpin_wait(
81	xfs_dquot_t *dqp)
82	{
83	ASSERT(XFS_DQ_IS_LOCKED(dqp));
84	- if (dqp->q_pincount == 0) {
85	+ if (atomic_read(&dqp->q_pincount) == 0) {
86	return;
87	}
88
89	@@ -201,13 +195,7 @@ xfs_qm_dqunpin_wait(
90	* Give the log a push so we don't wait here too long.
91	*/
92	xfs_log_force(dqp->q_mount, (xfs_lsn_t)0, XFS_LOG_FORCE);
93	- spin_lock(&(XFS_DQ_TO_QINF(dqp)->qi_pinlock));
94	- if (dqp->q_pincount == 0) {
95	- spin_unlock(&(XFS_DQ_TO_QINF(dqp)->qi_pinlock));
96	- return;
97	- }
98	- sv_wait(&(dqp->q_pinwait), PINOD,
99	- &(XFS_DQ_TO_QINF(dqp)->qi_pinlock), s);
100	+ wait_event(dqp->q_pinwait, (atomic_read(&dqp->q_pincount) == 0));
101	}
102
103	/*
104	@@ -310,7 +298,7 @@ xfs_qm_dquot_logitem_trylock(
105	uint retval;
106
107	dqp = qip->qli_dquot;
108	- if (dqp->q_pincount > 0)
109	+ if (atomic_read(&dqp->q_pincount) > 0)
110	return (XFS_ITEM_PINNED);
111
112	if (! xfs_qm_dqlock_nowait(dqp))
113	Index: linux/fs/xfs/quota/xfs_dquot.h
114	===================================================================
115	--- linux.orig/fs/xfs/quota/xfs_dquot.h 2008-10-09 17:13:53.000000000 -0500
116	+++ linux/fs/xfs/quota/xfs_dquot.h 2009-03-09 10:36:25.000000000 -0500
117	@@ -83,8 +83,9 @@ typedef struct xfs_dquot {
118	xfs_qcnt_t q_res_rtbcount;/* total realtime blks used+reserved */
119	mutex_t q_qlock; /* quota lock */
120	struct completion q_flush; /* flush completion queue */
121	- uint q_pincount; /* pin count for this dquot */
122	- sv_t q_pinwait; /* sync var for pinning */
123	+ atomic_t q_pincount; /* dquot pin count */
124	+ wait_queue_head_t q_pinwait; /* dquot pinning wait queue */
125	+
126	#ifdef XFS_DQUOT_TRACE
127	struct ktrace q_trace; / trace header structure */
128	#endif
129	Index: linux/fs/xfs/quota/xfs_dquot.c
130	===================================================================
131	--- linux.orig/fs/xfs/quota/xfs_dquot.c 2008-10-09 17:13:53.000000000 -0500
132	+++ linux/fs/xfs/quota/xfs_dquot.c 2009-03-09 10:38:06.000000000 -0500
133	@@ -101,7 +101,7 @@ xfs_qm_dqinit(
134	if (brandnewdquot) {
135	dqp->dq_flnext = dqp->dq_flprev = dqp;
136	mutex_init(&dqp->q_qlock);
137	- sv_init(&dqp->q_pinwait, SV_DEFAULT, "pdq");
138	+ init_waitqueue_head(&dqp->q_pinwait);
139
140	/*
141	* Because we want to use a counting completion, complete
142	@@ -131,7 +131,7 @@ xfs_qm_dqinit(
143	dqp->q_res_bcount = 0;
144	dqp->q_res_icount = 0;
145	dqp->q_res_rtbcount = 0;
146	- dqp->q_pincount = 0;
147	+ atomic_set(&dqp->q_pincount, 0);
148	dqp->q_hash = NULL;
149	ASSERT(dqp->dq_flnext == dqp->dq_flprev);
150
151	@@ -1489,7 +1489,7 @@ xfs_qm_dqpurge(
152	"xfs_qm_dqpurge: dquot %p flush failed", dqp);
153	xfs_dqflock(dqp);
154	}
155	- ASSERT(dqp->q_pincount == 0);
156	+ ASSERT(atomic_read(&dqp->q_pincount) == 0);
157	ASSERT(XFS_FORCED_SHUTDOWN(mp) \|\|
158	!(dqp->q_logitem.qli_item.li_flags & XFS_LI_IN_AIL));
159
160	Index: linux/fs/xfs/quota/xfs_qm.h
161	===================================================================
162	--- linux.orig/fs/xfs/quota/xfs_qm.h 2008-10-09 17:13:53.000000000 -0500
163	+++ linux/fs/xfs/quota/xfs_qm.h 2009-03-09 10:11:15.000000000 -0500
164	@@ -106,7 +106,6 @@ typedef struct xfs_qm {
165	typedef struct xfs_quotainfo {
166	xfs_inode_t qi_uquotaip; / user quota inode */
167	xfs_inode_t qi_gquotaip; / group quota inode */
168	- spinlock_t qi_pinlock; /* dquot pinning lock */
169	xfs_dqlist_t qi_dqlist; /* all dquots in filesys */
170	int qi_dqreclaims; /* a change here indicates
171	a removal in the dqlist */
172	Index: linux/fs/xfs/quota/xfs_qm.c
173	===================================================================
174	--- linux.orig/fs/xfs/quota/xfs_qm.c 2008-10-09 17:13:53.000000000 -0500
175	+++ linux/fs/xfs/quota/xfs_qm.c 2009-03-09 10:12:12.000000000 -0500
176	@@ -1137,7 +1137,6 @@ xfs_qm_init_quotainfo(
177	return error;
178	}
179
180	- spin_lock_init(&qinf->qi_pinlock);
181	xfs_qm_list_init(&qinf->qi_dqlist, "mpdqlist", 0);
182	qinf->qi_dqreclaims = 0;
183
184	@@ -1234,7 +1233,6 @@ xfs_qm_destroy_quotainfo(
185	*/
186	xfs_qm_rele_quotafs_ref(mp);
187
188	- spinlock_destroy(&qi->qi_pinlock);
189	xfs_qm_list_destroy(&qi->qi_dqlist);
190
191	if (qi->qi_uquotaip) {