X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=kernel%2Ftime%2Ftimer_stats.c;h=321693724ad743a74d81c2b3add00f3d4ee21237;hb=c1a834dc704763673df10282995257f2de93cbe9;hp=946ed45f7d2fd49cda8abe74fd6ec48c68c959dd;hpb=ffb45122766db220d0bf3d01848d575fbbcb6430;p=safe%2Fjmp%2Flinux-2.6

diff --git a/kernel/time/timer_stats.c b/kernel/time/timer_stats.c
index 946ed45..3216937 100644
--- a/kernel/time/timer_stats.c
+++ b/kernel/time/timer_stats.c
@@ -117,21 +117,6 @@ static struct entry entries[MAX_ENTRIES];
 
 static atomic_t overflow_count;
 
-static void reset_entries(void)
-{
-	nr_entries = 0;
-	memset(entries, 0, sizeof(entries));
-	atomic_set(&overflow_count, 0);
-}
-
-static struct entry *alloc_entry(void)
-{
-	if (nr_entries >= MAX_ENTRIES)
-		return NULL;
-
-	return entries + nr_entries++;
-}
-
 /*
  * The entries are in a hash-table, for fast lookup:
  */
@@ -149,6 +134,22 @@ static struct entry *alloc_entry(void)
 
 static struct entry *tstat_hash_table[TSTAT_HASH_SIZE] __read_mostly;
 
+static void reset_entries(void)
+{
+	nr_entries = 0;
+	memset(entries, 0, sizeof(entries));
+	memset(tstat_hash_table, 0, sizeof(tstat_hash_table));
+	atomic_set(&overflow_count, 0);
+}
+
+static struct entry *alloc_entry(void)
+{
+	if (nr_entries >= MAX_ENTRIES)
+		return NULL;
+
+	return entries + nr_entries++;
+}
+
 static int match_entries(struct entry *entry1, struct entry *entry2)
 {
 	return entry1->timer       == entry2->timer	  &&
@@ -202,12 +203,15 @@ static struct entry *tstat_lookup(struct entry *entry, char *comm)
 	if (curr) {
 		*curr = *entry;
 		curr->count = 0;
+		curr->next = NULL;
 		memcpy(curr->comm, comm, TASK_COMM_LEN);
+
+		smp_mb(); /* Ensure that curr is initialized before insert */
+
 		if (prev)
 			prev->next = curr;
 		else
 			*head = curr;
-		curr->next = NULL;
 	}
  out_unlock:
 	spin_unlock(&table_lock);
@@ -232,10 +236,15 @@ void timer_stats_update_stats(void *timer, pid_t pid, void *startf,
 	/*
 	 * It doesnt matter which lock we take:
 	 */
-	spinlock_t *lock = &per_cpu(lookup_lock, raw_smp_processor_id());
+	spinlock_t *lock;
 	struct entry *entry, input;
 	unsigned long flags;
 
+	if (likely(!active))
+		return;
+
+	lock = &per_cpu(lookup_lock, raw_smp_processor_id());
+
 	input.timer = timer;
 	input.start_func = startf;
 	input.expire_func = timerf;
@@ -257,14 +266,12 @@ void timer_stats_update_stats(void *timer, pid_t pid, void *startf,
 
 static void print_name_offset(struct seq_file *m, unsigned long addr)
 {
-	char namebuf[KSYM_NAME_LEN+1];
-	const char *sym_name;
+	char symname[KSYM_NAME_LEN+1];
 
-	sym_name = kallsyms_lookup(addr, NULL, NULL, NULL, namebuf);
-	if (sym_name)
-		seq_printf(m, "%s", sym_name);
-	else
+	if (lookup_symbol_name(addr, symname) < 0)
 		seq_printf(m, "<%p>", (void *)addr);
+	else
+		seq_printf(m, "%s", symname);
 }
 
 static int tstats_show(struct seq_file *m, void *v)
@@ -362,6 +369,7 @@ static ssize_t tstats_write(struct file *file, const char __user *buf,
 		if (!active) {
 			reset_entries();
 			time_start = ktime_get();
+			smp_mb();
 			active = 1;
 		}
 		break;