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Subject[PATCH v4 1/2] rcu: uninline rcu_lock_acquire() and rcu_lock_release()
Uninline rcu_lock_acquire() and rcu_lock_release() to shrink .text/data.
The difference in "size vmlinux" looks good,

with CONFIG_DEBUG_LOCK_ALLOC

- 5377829 3018320 14757888 23154037
+ 5352229 3010160 14757888 23120277

33760 bytes saved.

with CONFIG_DEBUG_LOCK_ALLOC + CONFIG_PROVE_RCU + CONFIG_TREE_RCU_TRACE

- 5678315 3027032 14757888 23463235
+ 5578795 3026776 14757888 23363459

saves 99776 bytes.

However, this obviously means that the "warn once" logic is moved from
the current callers of rcu_lockdep_assert(rcu_is_watching()) to update.c.

Also, with this patch we do not bother to report which function abused
rcu_is_watching(), this should be clear from dump_stack().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
include/linux/rcupdate.h | 60 +++++++++++++++++++++++----------------------
include/linux/srcu.h | 4 +-
kernel/rcu/rcu.h | 6 ++--
kernel/rcu/update.c | 53 ++++++++++++++++++++++++++++++++++++++++
4 files changed, 89 insertions(+), 34 deletions(-)

diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index d231aa1..b82d1d6 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -355,21 +355,28 @@ static inline bool rcu_lockdep_current_cpu_online(void)

#ifdef CONFIG_DEBUG_LOCK_ALLOC

-static inline void rcu_lock_acquire(struct lockdep_map *map)
+extern struct lockdep_map rcu_lock_map;
+extern struct lockdep_map rcu_bh_lock_map;
+extern struct lockdep_map rcu_sched_lock_map;
+extern struct lockdep_map rcu_callback_map;
+int debug_lockdep_rcu_enabled(void);
+
+static inline void __rcu_lock_acquire(struct lockdep_map *map, unsigned long ip)
{
- lock_acquire(map, 0, 0, 2, 0, NULL, _THIS_IP_);
+ lock_acquire(map, 0, 0, 2, 0, NULL, ip);
}

-static inline void rcu_lock_release(struct lockdep_map *map)
+static inline void __rcu_lock_release(struct lockdep_map *map, unsigned long ip)
{
- lock_release(map, 1, _THIS_IP_);
+ lock_release(map, 1, ip);
}

-extern struct lockdep_map rcu_lock_map;
-extern struct lockdep_map rcu_bh_lock_map;
-extern struct lockdep_map rcu_sched_lock_map;
-extern struct lockdep_map rcu_callback_map;
-int debug_lockdep_rcu_enabled(void);
+extern void rcu_lock_acquire(void);
+extern void rcu_lock_release(void);
+extern void rcu_lock_acquire_bh(void);
+extern void rcu_lock_release_bh(void);
+extern void rcu_lock_acquire_sched(void);
+extern void rcu_lock_release_sched(void);

/**
* rcu_read_lock_held() - might we be in RCU read-side critical section?
@@ -463,8 +470,15 @@ static inline int rcu_read_lock_sched_held(void)

#else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */

-# define rcu_lock_acquire(a) do { } while (0)
-# define rcu_lock_release(a) do { } while (0)
+#define __rcu_lock_acquire(map, ip) do { } while (0)
+#define __rcu_lock_release(map, ip) do { } while (0)
+
+#define rcu_lock_acquire() do { } while (0)
+#define rcu_lock_release() do { } while (0)
+#define rcu_lock_acquire_bh() do { } while (0)
+#define rcu_lock_release_bh() do { } while (0)
+#define rcu_lock_acquire_sched() do { } while (0)
+#define rcu_lock_release_sched() do { } while (0)

static inline int rcu_read_lock_held(void)
{
@@ -839,9 +853,7 @@ static inline void rcu_read_lock(void)
{
__rcu_read_lock();
__acquire(RCU);
- rcu_lock_acquire(&rcu_lock_map);
- rcu_lockdep_assert(rcu_is_watching(),
- "rcu_read_lock() used illegally while idle");
+ rcu_lock_acquire();
}

/*
@@ -889,9 +901,7 @@ static inline void rcu_read_lock(void)
*/
static inline void rcu_read_unlock(void)
{
- rcu_lockdep_assert(rcu_is_watching(),
- "rcu_read_unlock() used illegally while idle");
- rcu_lock_release(&rcu_lock_map);
+ rcu_lock_release();
__release(RCU);
__rcu_read_unlock();
}
@@ -917,9 +927,7 @@ static inline void rcu_read_lock_bh(void)
{
local_bh_disable();
__acquire(RCU_BH);
- rcu_lock_acquire(&rcu_bh_lock_map);
- rcu_lockdep_assert(rcu_is_watching(),
- "rcu_read_lock_bh() used illegally while idle");
+ rcu_lock_acquire_bh();
}

/*
@@ -929,9 +937,7 @@ static inline void rcu_read_lock_bh(void)
*/
static inline void rcu_read_unlock_bh(void)
{
- rcu_lockdep_assert(rcu_is_watching(),
- "rcu_read_unlock_bh() used illegally while idle");
- rcu_lock_release(&rcu_bh_lock_map);
+ rcu_lock_release_bh();
__release(RCU_BH);
local_bh_enable();
}
@@ -953,9 +959,7 @@ static inline void rcu_read_lock_sched(void)
{
preempt_disable();
__acquire(RCU_SCHED);
- rcu_lock_acquire(&rcu_sched_lock_map);
- rcu_lockdep_assert(rcu_is_watching(),
- "rcu_read_lock_sched() used illegally while idle");
+ rcu_lock_acquire_sched();
}

/* Used by lockdep and tracing: cannot be traced, cannot call lockdep. */
@@ -972,9 +976,7 @@ static inline notrace void rcu_read_lock_sched_notrace(void)
*/
static inline void rcu_read_unlock_sched(void)
{
- rcu_lockdep_assert(rcu_is_watching(),
- "rcu_read_unlock_sched() used illegally while idle");
- rcu_lock_release(&rcu_sched_lock_map);
+ rcu_lock_release_sched();
__release(RCU_SCHED);
preempt_enable();
}
diff --git a/include/linux/srcu.h b/include/linux/srcu.h
index a2783cb..5c06289 100644
--- a/include/linux/srcu.h
+++ b/include/linux/srcu.h
@@ -219,7 +219,7 @@ static inline int srcu_read_lock(struct srcu_struct *sp) __acquires(sp)
{
int retval = __srcu_read_lock(sp);

- rcu_lock_acquire(&(sp)->dep_map);
+ __rcu_lock_acquire(&(sp)->dep_map, _THIS_IP_);
return retval;
}

@@ -233,7 +233,7 @@ static inline int srcu_read_lock(struct srcu_struct *sp) __acquires(sp)
static inline void srcu_read_unlock(struct srcu_struct *sp, int idx)
__releases(sp)
{
- rcu_lock_release(&(sp)->dep_map);
+ __rcu_lock_release(&(sp)->dep_map, _THIS_IP_);
__srcu_read_unlock(sp, idx);
}

diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h
index ff1a6de..4782d2f 100644
--- a/kernel/rcu/rcu.h
+++ b/kernel/rcu/rcu.h
@@ -107,16 +107,16 @@ static inline bool __rcu_reclaim(const char *rn, struct rcu_head *head)
{
unsigned long offset = (unsigned long)head->func;

- rcu_lock_acquire(&rcu_callback_map);
+ __rcu_lock_acquire(&rcu_callback_map, _THIS_IP_);
if (__is_kfree_rcu_offset(offset)) {
RCU_TRACE(trace_rcu_invoke_kfree_callback(rn, head, offset));
kfree((void *)head - offset);
- rcu_lock_release(&rcu_callback_map);
+ __rcu_lock_release(&rcu_callback_map, _THIS_IP_);
return true;
} else {
RCU_TRACE(trace_rcu_invoke_callback(rn, head));
head->func(head);
- rcu_lock_release(&rcu_callback_map);
+ __rcu_lock_release(&rcu_callback_map, _THIS_IP_);
return false;
}
}
diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c
index 4056d79..c2209eb 100644
--- a/kernel/rcu/update.c
+++ b/kernel/rcu/update.c
@@ -163,6 +163,59 @@ int rcu_read_lock_bh_held(void)
}
EXPORT_SYMBOL_GPL(rcu_read_lock_bh_held);

+static void rcu_lockdep_assert_watching(void)
+{
+ rcu_lockdep_assert(rcu_is_watching(), "RCU used illegally while idle");
+}
+
+static void rcu_acquire_map(struct lockdep_map *map, unsigned long ip)
+{
+ __rcu_lock_acquire(map, ip);
+ rcu_lockdep_assert_watching();
+}
+
+static void rcu_release_map(struct lockdep_map *map, unsigned long ip)
+{
+ rcu_lockdep_assert_watching();
+ __rcu_lock_release(map, ip);
+}
+
+void rcu_lock_acquire(void)
+{
+ rcu_acquire_map(&rcu_lock_map, _RET_IP_);
+}
+EXPORT_SYMBOL(rcu_lock_acquire);
+
+void rcu_lock_release(void)
+{
+ rcu_release_map(&rcu_lock_map, _RET_IP_);
+}
+EXPORT_SYMBOL(rcu_lock_release);
+
+void rcu_lock_acquire_bh(void)
+{
+ rcu_acquire_map(&rcu_bh_lock_map, _RET_IP_);
+}
+EXPORT_SYMBOL(rcu_lock_acquire_bh);
+
+void rcu_lock_release_bh(void)
+{
+ rcu_release_map(&rcu_bh_lock_map, _RET_IP_);
+}
+EXPORT_SYMBOL(rcu_lock_release_bh);
+
+void rcu_lock_acquire_sched(void)
+{
+ rcu_acquire_map(&rcu_sched_lock_map, _RET_IP_);
+}
+EXPORT_SYMBOL(rcu_lock_acquire_sched);
+
+void rcu_lock_release_sched(void)
+{
+ rcu_release_map(&rcu_sched_lock_map, _RET_IP_);
+}
+EXPORT_SYMBOL(rcu_lock_release_sched);
+
#endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */

struct rcu_synchronize {
--
1.5.5.1


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