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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2008-12-26 15:08:55 +0100
committerIngo Molnar <mingo@elte.hu>2008-12-29 13:43:00 +0100
commitea319518ba3de282c13ae1cf4bf2215c5e03e67e (patch)
tree72eea2b8e5d8926e95ade18d610d59b13df5dae5
parent00ef9f7348dfd2fc223ec42aceb30836e86b367f (diff)
locking, percpu counters: introduce separate lock classes
Impact: fix lockdep false positives Classify percpu_counter instances similar to regular lock objects -- that is, per instantiation site. The networking code has increased its use of percpu_counters, which leads to false positives if they are treated as a single class. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
-rw-r--r--include/linux/percpu_counter.h14
-rw-r--r--lib/percpu_counter.c18
-rw-r--r--lib/proportions.c6
-rw-r--r--mm/backing-dev.c2
4 files changed, 18 insertions, 22 deletions
diff --git a/include/linux/percpu_counter.h b/include/linux/percpu_counter.h
index 9007ccdfc112..96bdde36599f 100644
--- a/include/linux/percpu_counter.h
+++ b/include/linux/percpu_counter.h
@@ -30,8 +30,16 @@ struct percpu_counter {
#define FBC_BATCH (NR_CPUS*4)
#endif
-int percpu_counter_init(struct percpu_counter *fbc, s64 amount);
-int percpu_counter_init_irq(struct percpu_counter *fbc, s64 amount);
+int __percpu_counter_init(struct percpu_counter *fbc, s64 amount,
+ struct lock_class_key *key);
+
+#define percpu_counter_init(fbc, value) \
+ ({ \
+ static struct lock_class_key __key; \
+ \
+ __percpu_counter_init(fbc, value, &__key); \
+ })
+
void percpu_counter_destroy(struct percpu_counter *fbc);
void percpu_counter_set(struct percpu_counter *fbc, s64 amount);
void __percpu_counter_add(struct percpu_counter *fbc, s64 amount, s32 batch);
@@ -85,8 +93,6 @@ static inline int percpu_counter_init(struct percpu_counter *fbc, s64 amount)
return 0;
}
-#define percpu_counter_init_irq percpu_counter_init
-
static inline void percpu_counter_destroy(struct percpu_counter *fbc)
{
}
diff --git a/lib/percpu_counter.c b/lib/percpu_counter.c
index a8663890a88c..c7fe2e4e8ed1 100644
--- a/lib/percpu_counter.c
+++ b/lib/percpu_counter.c
@@ -71,11 +71,11 @@ s64 __percpu_counter_sum(struct percpu_counter *fbc)
}
EXPORT_SYMBOL(__percpu_counter_sum);
-static struct lock_class_key percpu_counter_irqsafe;
-
-int percpu_counter_init(struct percpu_counter *fbc, s64 amount)
+int __percpu_counter_init(struct percpu_counter *fbc, s64 amount,
+ struct lock_class_key *key)
{
spin_lock_init(&fbc->lock);
+ lockdep_set_class(&fbc->lock, key);
fbc->count = amount;
fbc->counters = alloc_percpu(s32);
if (!fbc->counters)
@@ -87,17 +87,7 @@ int percpu_counter_init(struct percpu_counter *fbc, s64 amount)
#endif
return 0;
}
-EXPORT_SYMBOL(percpu_counter_init);
-
-int percpu_counter_init_irq(struct percpu_counter *fbc, s64 amount)
-{
- int err;
-
- err = percpu_counter_init(fbc, amount);
- if (!err)
- lockdep_set_class(&fbc->lock, &percpu_counter_irqsafe);
- return err;
-}
+EXPORT_SYMBOL(__percpu_counter_init);
void percpu_counter_destroy(struct percpu_counter *fbc)
{
diff --git a/lib/proportions.c b/lib/proportions.c
index 4f387a643d72..7367f2b727d0 100644
--- a/lib/proportions.c
+++ b/lib/proportions.c
@@ -83,11 +83,11 @@ int prop_descriptor_init(struct prop_descriptor *pd, int shift)
pd->index = 0;
pd->pg[0].shift = shift;
mutex_init(&pd->mutex);
- err = percpu_counter_init_irq(&pd->pg[0].events, 0);
+ err = percpu_counter_init(&pd->pg[0].events, 0);
if (err)
goto out;
- err = percpu_counter_init_irq(&pd->pg[1].events, 0);
+ err = percpu_counter_init(&pd->pg[1].events, 0);
if (err)
percpu_counter_destroy(&pd->pg[0].events);
@@ -191,7 +191,7 @@ int prop_local_init_percpu(struct prop_local_percpu *pl)
spin_lock_init(&pl->lock);
pl->shift = 0;
pl->period = 0;
- return percpu_counter_init_irq(&pl->events, 0);
+ return percpu_counter_init(&pl->events, 0);
}
void prop_local_destroy_percpu(struct prop_local_percpu *pl)
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index f2e574dbc300..f3b125857827 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -220,7 +220,7 @@ int bdi_init(struct backing_dev_info *bdi)
bdi->max_prop_frac = PROP_FRAC_BASE;
for (i = 0; i < NR_BDI_STAT_ITEMS; i++) {
- err = percpu_counter_init_irq(&bdi->bdi_stat[i], 0);
+ err = percpu_counter_init(&bdi->bdi_stat[i], 0);
if (err)
goto err;
}