[PATCH] spinlock consolidation
This patch (written by me and also containing many suggestions of Arjan van
de Ven) does a major cleanup of the spinlock code. It does the following
things:
- consolidates and enhances the spinlock/rwlock debugging code
- simplifies the asm/spinlock.h files
- encapsulates the raw spinlock type and moves generic spinlock
features (such as ->break_lock) into the generic code.
- cleans up the spinlock code hierarchy to get rid of the spaghetti.
Most notably there's now only a single variant of the debugging code,
located in lib/spinlock_debug.c. (previously we had one SMP debugging
variant per architecture, plus a separate generic one for UP builds)
Also, i've enhanced the rwlock debugging facility, it will now track
write-owners. There is new spinlock-owner/CPU-tracking on SMP builds too.
All locks have lockup detection now, which will work for both soft and hard
spin/rwlock lockups.
The arch-level include files now only contain the minimally necessary
subset of the spinlock code - all the rest that can be generalized now
lives in the generic headers:
include/asm-i386/spinlock_types.h | 16
include/asm-x86_64/spinlock_types.h | 16
I have also split up the various spinlock variants into separate files,
making it easier to see which does what. The new layout is:
SMP | UP
----------------------------|-----------------------------------
asm/spinlock_types_smp.h | linux/spinlock_types_up.h
linux/spinlock_types.h | linux/spinlock_types.h
asm/spinlock_smp.h | linux/spinlock_up.h
linux/spinlock_api_smp.h | linux/spinlock_api_up.h
linux/spinlock.h | linux/spinlock.h
/*
* here's the role of the various spinlock/rwlock related include files:
*
* on SMP builds:
*
* asm/spinlock_types.h: contains the raw_spinlock_t/raw_rwlock_t and the
* initializers
*
* linux/spinlock_types.h:
* defines the generic type and initializers
*
* asm/spinlock.h: contains the __raw_spin_*()/etc. lowlevel
* implementations, mostly inline assembly code
*
* (also included on UP-debug builds:)
*
* linux/spinlock_api_smp.h:
* contains the prototypes for the _spin_*() APIs.
*
* linux/spinlock.h: builds the final spin_*() APIs.
*
* on UP builds:
*
* linux/spinlock_type_up.h:
* contains the generic, simplified UP spinlock type.
* (which is an empty structure on non-debug builds)
*
* linux/spinlock_types.h:
* defines the generic type and initializers
*
* linux/spinlock_up.h:
* contains the __raw_spin_*()/etc. version of UP
* builds. (which are NOPs on non-debug, non-preempt
* builds)
*
* (included on UP-non-debug builds:)
*
* linux/spinlock_api_up.h:
* builds the _spin_*() APIs.
*
* linux/spinlock.h: builds the final spin_*() APIs.
*/
All SMP and UP architectures are converted by this patch.
arm, i386, ia64, ppc, ppc64, s390/s390x, x64 was build-tested via
crosscompilers. m32r, mips, sh, sparc, have not been tested yet, but should
be mostly fine.
From: Grant Grundler <grundler@parisc-linux.org>
Booted and lightly tested on a500-44 (64-bit, SMP kernel, dual CPU).
Builds 32-bit SMP kernel (not booted or tested). I did not try to build
non-SMP kernels. That should be trivial to fix up later if necessary.
I converted bit ops atomic_hash lock to raw_spinlock_t. Doing so avoids
some ugly nesting of linux/*.h and asm/*.h files. Those particular locks
are well tested and contained entirely inside arch specific code. I do NOT
expect any new issues to arise with them.
If someone does ever need to use debug/metrics with them, then they will
need to unravel this hairball between spinlocks, atomic ops, and bit ops
that exist only because parisc has exactly one atomic instruction: LDCW
(load and clear word).
From: "Luck, Tony" <tony.luck@intel.com>
ia64 fix
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjanv@infradead.org>
Signed-off-by: Grant Grundler <grundler@parisc-linux.org>
Cc: Matthew Wilcox <willy@debian.org>
Signed-off-by: Hirokazu Takata <takata@linux-m32r.org>
Signed-off-by: Mikael Pettersson <mikpe@csd.uu.se>
Signed-off-by: Benoit Boissinot <benoit.boissinot@ens-lyon.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/include/asm-parisc/spinlock.h b/include/asm-parisc/spinlock.h
index 679ea1c..43eaa6e 100644
--- a/include/asm-parisc/spinlock.h
+++ b/include/asm-parisc/spinlock.h
@@ -2,30 +2,25 @@
#define __ASM_SPINLOCK_H
#include <asm/system.h>
+#include <asm/processor.h>
+#include <asm/spinlock_types.h>
/* Note that PA-RISC has to use `1' to mean unlocked and `0' to mean locked
* since it only has load-and-zero. Moreover, at least on some PA processors,
* the semaphore address has to be 16-byte aligned.
*/
-#ifndef CONFIG_DEBUG_SPINLOCK
-
-#define __SPIN_LOCK_UNLOCKED { { 1, 1, 1, 1 } }
-#undef SPIN_LOCK_UNLOCKED
-#define SPIN_LOCK_UNLOCKED (spinlock_t) __SPIN_LOCK_UNLOCKED
-
-#define spin_lock_init(x) do { *(x) = SPIN_LOCK_UNLOCKED; } while(0)
-
-static inline int spin_is_locked(spinlock_t *x)
+static inline int __raw_spin_is_locked(raw_spinlock_t *x)
{
volatile unsigned int *a = __ldcw_align(x);
return *a == 0;
}
-#define spin_unlock_wait(x) do { barrier(); } while(spin_is_locked(x))
-#define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock)
+#define __raw_spin_lock_flags(lock, flags) __raw_spin_lock(lock)
+#define __raw_spin_unlock_wait(x) \
+ do { cpu_relax(); } while (__raw_spin_is_locked(x))
-static inline void _raw_spin_lock(spinlock_t *x)
+static inline void __raw_spin_lock(raw_spinlock_t *x)
{
volatile unsigned int *a;
@@ -36,7 +31,7 @@
mb();
}
-static inline void _raw_spin_unlock(spinlock_t *x)
+static inline void __raw_spin_unlock(raw_spinlock_t *x)
{
volatile unsigned int *a;
mb();
@@ -45,7 +40,7 @@
mb();
}
-static inline int _raw_spin_trylock(spinlock_t *x)
+static inline int __raw_spin_trylock(raw_spinlock_t *x)
{
volatile unsigned int *a;
int ret;
@@ -57,131 +52,38 @@
return ret;
}
-
-#define spin_lock_own(LOCK, LOCATION) ((void)0)
-
-#else /* !(CONFIG_DEBUG_SPINLOCK) */
-
-#define SPINLOCK_MAGIC 0x1D244B3C
-
-#define __SPIN_LOCK_UNLOCKED { { 1, 1, 1, 1 }, SPINLOCK_MAGIC, 10, __FILE__ , NULL, 0, -1, NULL, NULL }
-#undef SPIN_LOCK_UNLOCKED
-#define SPIN_LOCK_UNLOCKED (spinlock_t) __SPIN_LOCK_UNLOCKED
-
-#define spin_lock_init(x) do { *(x) = SPIN_LOCK_UNLOCKED; } while(0)
-
-#define CHECK_LOCK(x) \
- do { \
- if (unlikely((x)->magic != SPINLOCK_MAGIC)) { \
- printk(KERN_ERR "%s:%d: spin_is_locked" \
- " on uninitialized spinlock %p.\n", \
- __FILE__, __LINE__, (x)); \
- } \
- } while(0)
-
-#define spin_is_locked(x) \
- ({ \
- CHECK_LOCK(x); \
- volatile unsigned int *a = __ldcw_align(x); \
- if (unlikely((*a == 0) && (x)->babble)) { \
- (x)->babble--; \
- printk("KERN_WARNING \
- %s:%d: spin_is_locked(%s/%p) already" \
- " locked by %s:%d in %s at %p(%d)\n", \
- __FILE__,__LINE__, (x)->module, (x), \
- (x)->bfile, (x)->bline, (x)->task->comm,\
- (x)->previous, (x)->oncpu); \
- } \
- *a == 0; \
- })
-
-#define spin_unlock_wait(x) \
- do { \
- CHECK_LOCK(x); \
- volatile unsigned int *a = __ldcw_align(x); \
- if (unlikely((*a == 0) && (x)->babble)) { \
- (x)->babble--; \
- printk("KERN_WARNING \
- %s:%d: spin_unlock_wait(%s/%p)" \
- " owned by %s:%d in %s at %p(%d)\n", \
- __FILE__,__LINE__, (x)->module, (x), \
- (x)->bfile, (x)->bline, (x)->task->comm,\
- (x)->previous, (x)->oncpu); \
- } \
- barrier(); \
- } while (*((volatile unsigned char *)(__ldcw_align(x))) == 0)
-
-extern void _dbg_spin_lock(spinlock_t *lock, const char *base_file, int line_no);
-extern void _dbg_spin_unlock(spinlock_t *lock, const char *, int);
-extern int _dbg_spin_trylock(spinlock_t * lock, const char *, int);
-
-#define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock)
-
-#define _raw_spin_unlock(lock) _dbg_spin_unlock(lock, __FILE__, __LINE__)
-#define _raw_spin_lock(lock) _dbg_spin_lock(lock, __FILE__, __LINE__)
-#define _raw_spin_trylock(lock) _dbg_spin_trylock(lock, __FILE__, __LINE__)
-
-/* just in case we need it */
-#define spin_lock_own(LOCK, LOCATION) \
-do { \
- volatile unsigned int *a = __ldcw_align(LOCK); \
- if (!((*a == 0) && ((LOCK)->oncpu == smp_processor_id()))) \
- printk("KERN_WARNING \
- %s: called on %d from %p but lock %s on %d\n", \
- LOCATION, smp_processor_id(), \
- __builtin_return_address(0), \
- (*a == 0) ? "taken" : "freed", (LOCK)->on_cpu); \
-} while (0)
-
-#endif /* !(CONFIG_DEBUG_SPINLOCK) */
/*
* Read-write spinlocks, allowing multiple readers
* but only one writer.
*/
-typedef struct {
- spinlock_t lock;
- volatile int counter;
-#ifdef CONFIG_PREEMPT
- unsigned int break_lock;
-#endif
-} rwlock_t;
-#define RW_LOCK_UNLOCKED (rwlock_t) { __SPIN_LOCK_UNLOCKED, 0 }
-
-#define rwlock_init(lp) do { *(lp) = RW_LOCK_UNLOCKED; } while (0)
-
-#define _raw_read_trylock(lock) generic_raw_read_trylock(lock)
+#define __raw_read_trylock(lock) generic__raw_read_trylock(lock)
/* read_lock, read_unlock are pretty straightforward. Of course it somehow
* sucks we end up saving/restoring flags twice for read_lock_irqsave aso. */
-#ifdef CONFIG_DEBUG_RWLOCK
-extern void _dbg_read_lock(rwlock_t * rw, const char *bfile, int bline);
-#define _raw_read_lock(rw) _dbg_read_lock(rw, __FILE__, __LINE__)
-#else
-static __inline__ void _raw_read_lock(rwlock_t *rw)
+static __inline__ void __raw_read_lock(raw_rwlock_t *rw)
{
unsigned long flags;
local_irq_save(flags);
- _raw_spin_lock(&rw->lock);
+ __raw_spin_lock(&rw->lock);
rw->counter++;
- _raw_spin_unlock(&rw->lock);
+ __raw_spin_unlock(&rw->lock);
local_irq_restore(flags);
}
-#endif /* CONFIG_DEBUG_RWLOCK */
-static __inline__ void _raw_read_unlock(rwlock_t *rw)
+static __inline__ void __raw_read_unlock(raw_rwlock_t *rw)
{
unsigned long flags;
local_irq_save(flags);
- _raw_spin_lock(&rw->lock);
+ __raw_spin_lock(&rw->lock);
rw->counter--;
- _raw_spin_unlock(&rw->lock);
+ __raw_spin_unlock(&rw->lock);
local_irq_restore(flags);
}
@@ -194,20 +96,17 @@
* writers) in interrupt handlers someone fucked up and we'd dead-lock
* sooner or later anyway. prumpf */
-#ifdef CONFIG_DEBUG_RWLOCK
-extern void _dbg_write_lock(rwlock_t * rw, const char *bfile, int bline);
-#define _raw_write_lock(rw) _dbg_write_lock(rw, __FILE__, __LINE__)
-#else
-static __inline__ void _raw_write_lock(rwlock_t *rw)
+static __inline__ void __raw_write_lock(raw_rwlock_t *rw)
{
retry:
- _raw_spin_lock(&rw->lock);
+ __raw_spin_lock(&rw->lock);
if(rw->counter != 0) {
/* this basically never happens */
- _raw_spin_unlock(&rw->lock);
+ __raw_spin_unlock(&rw->lock);
- while(rw->counter != 0);
+ while (rw->counter != 0)
+ cpu_relax();
goto retry;
}
@@ -215,26 +114,21 @@
/* got it. now leave without unlocking */
rw->counter = -1; /* remember we are locked */
}
-#endif /* CONFIG_DEBUG_RWLOCK */
/* write_unlock is absolutely trivial - we don't have to wait for anything */
-static __inline__ void _raw_write_unlock(rwlock_t *rw)
+static __inline__ void __raw_write_unlock(raw_rwlock_t *rw)
{
rw->counter = 0;
- _raw_spin_unlock(&rw->lock);
+ __raw_spin_unlock(&rw->lock);
}
-#ifdef CONFIG_DEBUG_RWLOCK
-extern int _dbg_write_trylock(rwlock_t * rw, const char *bfile, int bline);
-#define _raw_write_trylock(rw) _dbg_write_trylock(rw, __FILE__, __LINE__)
-#else
-static __inline__ int _raw_write_trylock(rwlock_t *rw)
+static __inline__ int __raw_write_trylock(raw_rwlock_t *rw)
{
- _raw_spin_lock(&rw->lock);
+ __raw_spin_lock(&rw->lock);
if (rw->counter != 0) {
/* this basically never happens */
- _raw_spin_unlock(&rw->lock);
+ __raw_spin_unlock(&rw->lock);
return 0;
}
@@ -243,14 +137,13 @@
rw->counter = -1; /* remember we are locked */
return 1;
}
-#endif /* CONFIG_DEBUG_RWLOCK */
-static __inline__ int is_read_locked(rwlock_t *rw)
+static __inline__ int __raw_is_read_locked(raw_rwlock_t *rw)
{
return rw->counter > 0;
}
-static __inline__ int is_write_locked(rwlock_t *rw)
+static __inline__ int __raw_is_write_locked(raw_rwlock_t *rw)
{
return rw->counter < 0;
}