X-Git-Url: http://git.efficios.com/?a=blobdiff_plain;f=fs%2Fxfs%2Fsupport%2Fktrace.c;h=a34ef05489b1c323369c7b22cf40400febaa28dd;hb=f0e2d93c29dc39ffd24cac180a19d48f700c0706;hp=addf5a7ea06c40f879d40d1e8117c15cf01e21c5;hpb=95d465fd750897ab32462a6702fbfe1b122cbbc0;p=deliverable%2Flinux.git

diff --git a/fs/xfs/support/ktrace.c b/fs/xfs/support/ktrace.c
index addf5a7ea06c..a34ef05489b1 100644
--- a/fs/xfs/support/ktrace.c
+++ b/fs/xfs/support/ktrace.c
@@ -21,10 +21,10 @@ static kmem_zone_t *ktrace_hdr_zone;
 static kmem_zone_t *ktrace_ent_zone;
 static int          ktrace_zentries;
 
-void
+void __init
 ktrace_init(int zentries)
 {
-	ktrace_zentries = zentries;
+	ktrace_zentries = roundup_pow_of_two(zentries);
 
 	ktrace_hdr_zone = kmem_zone_init(sizeof(ktrace_t),
 					"ktrace_hdr");
@@ -36,7 +36,7 @@ ktrace_init(int zentries)
 	ASSERT(ktrace_ent_zone);
 }
 
-void
+void __exit
 ktrace_uninit(void)
 {
 	kmem_zone_destroy(ktrace_hdr_zone);
@@ -47,13 +47,16 @@ ktrace_uninit(void)
  * ktrace_alloc()
  *
  * Allocate a ktrace header and enough buffering for the given
- * number of entries.
+ * number of entries. Round the number of entries up to a
+ * power of 2 so we can do fast masking to get the index from
+ * the atomic index counter.
  */
 ktrace_t *
 ktrace_alloc(int nentries, unsigned int __nocast sleep)
 {
 	ktrace_t        *ktp;
 	ktrace_entry_t  *ktep;
+	int		entries;
 
 	ktp = (ktrace_t*)kmem_zone_alloc(ktrace_hdr_zone, sleep);
 
@@ -70,12 +73,13 @@ ktrace_alloc(int nentries, unsigned int __nocast sleep)
 	/*
 	 * Special treatment for buffers with the ktrace_zentries entries
 	 */
-	if (nentries == ktrace_zentries) {
+	entries = roundup_pow_of_two(nentries);
+	if (entries == ktrace_zentries) {
 		ktep = (ktrace_entry_t*)kmem_zone_zalloc(ktrace_ent_zone,
 							    sleep);
 	} else {
-		ktep = (ktrace_entry_t*)kmem_zalloc((nentries * sizeof(*ktep)),
-							    sleep);
+		ktep = (ktrace_entry_t*)kmem_zalloc((entries * sizeof(*ktep)),
+							    sleep | KM_LARGE);
 	}
 
 	if (ktep == NULL) {
@@ -85,16 +89,16 @@ ktrace_alloc(int nentries, unsigned int __nocast sleep)
 		if (sleep & KM_SLEEP)
 			panic("ktrace_alloc: NULL memory on KM_SLEEP request!");
 
-		kmem_free(ktp, sizeof(*ktp));
+		kmem_free(ktp);
 
 		return NULL;
 	}
 
-	spinlock_init(&(ktp->kt_lock), "kt_lock");
-
 	ktp->kt_entries  = ktep;
-	ktp->kt_nentries = nentries;
-	ktp->kt_index    = 0;
+	ktp->kt_nentries = entries;
+	ASSERT(is_power_of_2(entries));
+	ktp->kt_index_mask = entries - 1;
+	atomic_set(&ktp->kt_index, 0);
 	ktp->kt_rollover = 0;
 	return ktp;
 }
@@ -114,8 +118,6 @@ ktrace_free(ktrace_t *ktp)
 	if (ktp == (ktrace_t *)NULL)
 		return;
 
-	spinlock_destroy(&ktp->kt_lock);
-
 	/*
 	 * Special treatment for the Vnode trace buffer.
 	 */
@@ -124,7 +126,7 @@ ktrace_free(ktrace_t *ktp)
 	} else {
 		entries_size = (int)(ktp->kt_nentries * sizeof(ktrace_entry_t));
 
-		kmem_free(ktp->kt_entries, entries_size);
+		kmem_free(ktp->kt_entries);
 	}
 
 	kmem_zone_free(ktrace_hdr_zone, ktp);
@@ -155,8 +157,6 @@ ktrace_enter(
 	void            *val14,
 	void            *val15)
 {
-	static DEFINE_SPINLOCK(wrap_lock);
-	unsigned long	flags;
 	int             index;
 	ktrace_entry_t  *ktep;
 
@@ -165,12 +165,8 @@ ktrace_enter(
 	/*
 	 * Grab an entry by pushing the index up to the next one.
 	 */
-	spin_lock_irqsave(&wrap_lock, flags);
-	index = ktp->kt_index;
-	if (++ktp->kt_index == ktp->kt_nentries)
-		ktp->kt_index = 0;
-	spin_unlock_irqrestore(&wrap_lock, flags);
-
+	index = atomic_add_return(1, &ktp->kt_index);
+	index = (index - 1) & ktp->kt_index_mask;
 	if (!ktp->kt_rollover && index == ktp->kt_nentries - 1)
 		ktp->kt_rollover = 1;
 
@@ -203,11 +199,12 @@ int
 ktrace_nentries(
 	ktrace_t        *ktp)
 {
-	if (ktp == NULL) {
+	int	index;
+	if (ktp == NULL)
 		return 0;
-	}
 
-	return (ktp->kt_rollover ? ktp->kt_nentries : ktp->kt_index);
+	index = atomic_read(&ktp->kt_index) & ktp->kt_index_mask;
+	return (ktp->kt_rollover ? ktp->kt_nentries : index);
 }
 
 /*
@@ -232,7 +229,7 @@ ktrace_first(ktrace_t   *ktp, ktrace_snap_t     *ktsp)
 	int             nentries;
 
 	if (ktp->kt_rollover)
-		index = ktp->kt_index;
+		index = atomic_read(&ktp->kt_index) & ktp->kt_index_mask;
 	else
 		index = 0;