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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH v3 11/13] xen/spinlock: split recursive spinlocks from normal ones
Recursive and normal spinlocks are sharing the same data structure for
representation of the lock. This has two major disadvantages:
- it is not clear from the definition of a lock, whether it is intended
to be used recursive or not, while a mixture of both usage variants
needs to be
- in production builds (builds without CONFIG_DEBUG_LOCKS) the needed
data size of an ordinary spinlock is 8 bytes instead of 4, due to the
additional recursion data needed (associated with that the rwlock
data is using 12 instead of only 8 bytes)
Fix that by introducing a struct spinlock_recursive for recursive
spinlocks only, and switch recursive spinlock functions to require
pointers to this new struct.
This allows to check the correct usage at build time.
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
V2:
- use shorter names (Jan Beulich)
- don't embed spinlock_t in rspinlock_t (Jan Beulich)
---
xen/common/spinlock.c | 49 ++++++++++++++++++++++++++++++++
xen/include/xen/spinlock.h | 58 +++++++++++++++++++++++++-------------
2 files changed, 88 insertions(+), 19 deletions(-)
diff --git a/xen/common/spinlock.c b/xen/common/spinlock.c
index 8bb6691b14..0467541f43 100644
--- a/xen/common/spinlock.c
+++ b/xen/common/spinlock.c
@@ -541,6 +541,55 @@ void rspin_unlock_irqrestore(rspinlock_t *lock, unsigned
long flags)
local_irq_restore(flags);
}
+int nrspin_trylock(rspinlock_t *lock)
+{
+ check_lock(&lock->debug, true);
+
+ if ( unlikely(lock->recurse_cpu != SPINLOCK_NO_CPU) )
+ return 0;
+
+ return spin_trylock_common(&lock->tickets, &lock->debug, LOCK_PROFILE_PAR);
+}
+
+void nrspin_lock(rspinlock_t *lock)
+{
+ spin_lock_common(&lock->tickets, &lock->debug, LOCK_PROFILE_PAR, NULL,
+ NULL);
+}
+
+void nrspin_unlock(rspinlock_t *lock)
+{
+ spin_unlock_common(&lock->tickets, &lock->debug, LOCK_PROFILE_PAR);
+}
+
+void nrspin_lock_irq(rspinlock_t *lock)
+{
+ ASSERT(local_irq_is_enabled());
+ local_irq_disable();
+ nrspin_lock(lock);
+}
+
+void nrspin_unlock_irq(rspinlock_t *lock)
+{
+ nrspin_unlock(lock);
+ local_irq_enable();
+}
+
+unsigned long __nrspin_lock_irqsave(rspinlock_t *lock)
+{
+ unsigned long flags;
+
+ local_irq_save(flags);
+ nrspin_lock(lock);
+ return flags;
+}
+
+void nrspin_unlock_irqrestore(rspinlock_t *lock, unsigned long flags)
+{
+ nrspin_unlock(lock);
+ local_irq_restore(flags);
+}
+
#ifdef CONFIG_DEBUG_LOCK_PROFILE
struct lock_profile_anc {
diff --git a/xen/include/xen/spinlock.h b/xen/include/xen/spinlock.h
index fb6ca1949a..a2b1bb2df6 100644
--- a/xen/include/xen/spinlock.h
+++ b/xen/include/xen/spinlock.h
@@ -76,8 +76,6 @@ union lock_debug { };
*/
struct spinlock;
-/* Temporary hack until a dedicated struct rspinlock is existing. */
-#define rspinlock spinlock
struct lock_profile {
struct lock_profile *next; /* forward link */
@@ -108,6 +106,10 @@ struct lock_profile_qhead {
__used_section(".lockprofile.data") = \
&__lock_profile_data_##name
#define _SPIN_LOCK_UNLOCKED(x) { \
+ .debug =_LOCK_DEBUG, \
+ .profile = x, \
+}
+#define _RSPIN_LOCK_UNLOCKED(x) { \
.recurse_cpu = SPINLOCK_NO_CPU, \
.debug =_LOCK_DEBUG, \
.profile = x, \
@@ -117,8 +119,9 @@ struct lock_profile_qhead {
spinlock_t l = _SPIN_LOCK_UNLOCKED(NULL); \
static struct lock_profile __lock_profile_data_##l = _LOCK_PROFILE(l); \
_LOCK_PROFILE_PTR(l)
+#define RSPIN_LOCK_UNLOCKED _RSPIN_LOCK_UNLOCKED(NULL)
#define DEFINE_RSPINLOCK(l) \
- rspinlock_t l = _SPIN_LOCK_UNLOCKED(NULL); \
+ rspinlock_t l = _RSPIN_LOCK_UNLOCKED(NULL); \
static struct lock_profile __lock_profile_data_##l = _RLOCK_PROFILE(l); \
_LOCK_PROFILE_PTR(l)
@@ -143,8 +146,11 @@ struct lock_profile_qhead {
#define spin_lock_init_prof(s, l) \
__spin_lock_init_prof(s, l, lock, spinlock_t, 0)
-#define rspin_lock_init_prof(s, l) \
- __spin_lock_init_prof(s, l, rlock, rspinlock_t, 1)
+#define rspin_lock_init_prof(s, l) do { \
+ __spin_lock_init_prof(s, l, rlock, rspinlock_t, 1); \
+ (s)->l.recurse_cpu = SPINLOCK_NO_CPU; \
+ (s)->l.recurse_cnt = 0; \
+ } while (0)
void _lock_profile_register_struct(
int32_t type, struct lock_profile_qhead *qhead, int32_t idx);
@@ -166,11 +172,15 @@ struct lock_profile_qhead { };
struct lock_profile { };
#define SPIN_LOCK_UNLOCKED { \
+ .debug =_LOCK_DEBUG, \
+}
+#define RSPIN_LOCK_UNLOCKED { \
+ .debug =_LOCK_DEBUG, \
.recurse_cpu = SPINLOCK_NO_CPU, \
.debug =_LOCK_DEBUG, \
}
#define DEFINE_SPINLOCK(l) spinlock_t l = SPIN_LOCK_UNLOCKED
-#define DEFINE_RSPINLOCK(l) rspinlock_t l = SPIN_LOCK_UNLOCKED
+#define DEFINE_RSPINLOCK(l) rspinlock_t l = RSPIN_LOCK_UNLOCKED
#define spin_lock_init_prof(s, l) spin_lock_init(&((s)->l))
#define rspin_lock_init_prof(s, l) rspin_lock_init(&((s)->l))
@@ -180,7 +190,6 @@ struct lock_profile { };
#endif
-
typedef union {
uint32_t head_tail;
struct {
@@ -192,6 +201,14 @@ typedef union {
#define SPINLOCK_TICKET_INC { .head_tail = 0x10000, }
typedef struct spinlock {
+ spinlock_tickets_t tickets;
+ union lock_debug debug;
+#ifdef CONFIG_DEBUG_LOCK_PROFILE
+ struct lock_profile *profile;
+#endif
+} spinlock_t;
+
+typedef struct rspinlock {
spinlock_tickets_t tickets;
uint16_t recurse_cpu:SPINLOCK_CPU_BITS;
#define SPINLOCK_NO_CPU ((1u << SPINLOCK_CPU_BITS) - 1)
@@ -202,12 +219,10 @@ typedef struct spinlock {
#ifdef CONFIG_DEBUG_LOCK_PROFILE
struct lock_profile *profile;
#endif
-} spinlock_t;
-
-typedef spinlock_t rspinlock_t;
+} rspinlock_t;
#define spin_lock_init(l) (*(l) = (spinlock_t)SPIN_LOCK_UNLOCKED)
-#define rspin_lock_init(l) (*(l) = (rspinlock_t)SPIN_LOCK_UNLOCKED)
+#define rspin_lock_init(l) (*(l) = (rspinlock_t)RSPIN_LOCK_UNLOCKED)
void _spin_lock(spinlock_t *lock);
void _spin_lock_cb(spinlock_t *lock, void (*cb)(void *), void *data);
@@ -242,6 +257,19 @@ void rspin_unlock_irqrestore(rspinlock_t *lock, unsigned
long flags);
int rspin_is_locked(const rspinlock_t *lock);
void rspin_barrier(rspinlock_t *lock);
+int nrspin_trylock(rspinlock_t *lock);
+void nrspin_lock(rspinlock_t *lock);
+void nrspin_unlock(rspinlock_t *lock);
+void nrspin_lock_irq(rspinlock_t *lock);
+void nrspin_unlock_irq(rspinlock_t *lock);
+#define nrspin_lock_irqsave(l, f) \
+ ({ \
+ BUILD_BUG_ON(sizeof(f) != sizeof(unsigned long)); \
+ ((f) = __nrspin_lock_irqsave(l)); \
+ })
+unsigned long __nrspin_lock_irqsave(rspinlock_t *lock);
+void nrspin_unlock_irqrestore(rspinlock_t *lock, unsigned long flags);
+
#define spin_lock(l) _spin_lock(l)
#define spin_lock_cb(l, c, d) _spin_lock_cb(l, c, d)
#define spin_lock_irq(l) _spin_lock_irq(l)
@@ -270,12 +298,4 @@ void rspin_barrier(rspinlock_t *lock);
/* Ensure a lock is quiescent between two critical operations. */
#define spin_barrier(l) _spin_barrier(l)
-#define nrspin_trylock(l) spin_trylock(l)
-#define nrspin_lock(l) spin_lock(l)
-#define nrspin_unlock(l) spin_unlock(l)
-#define nrspin_lock_irq(l) spin_lock_irq(l)
-#define nrspin_unlock_irq(l) spin_unlock_irq(l)
-#define nrspin_lock_irqsave(l, f) spin_lock_irqsave(l, f)
-#define nrspin_unlock_irqrestore(l, f) spin_unlock_irqrestore(l, f)
-
#endif /* __SPINLOCK_H__ */
--
2.35.3
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