[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-sparc/spinlock.h b/include/asm-sparc/spinlock.h
index 0cbd87a..111727a 100644
--- a/include/asm-sparc/spinlock.h
+++ b/include/asm-sparc/spinlock.h
@@ -12,96 +12,12 @@
#include <asm/psr.h>
-#ifdef CONFIG_DEBUG_SPINLOCK
-struct _spinlock_debug {
- unsigned char lock;
- unsigned long owner_pc;
-#ifdef CONFIG_PREEMPT
- unsigned int break_lock;
-#endif
-};
-typedef struct _spinlock_debug spinlock_t;
+#define __raw_spin_is_locked(lock) (*((volatile unsigned char *)(lock)) != 0)
-#define SPIN_LOCK_UNLOCKED (spinlock_t) { 0, 0 }
-#define spin_lock_init(lp) do { *(lp)= SPIN_LOCK_UNLOCKED; } while(0)
-#define spin_is_locked(lp) (*((volatile unsigned char *)(&((lp)->lock))) != 0)
-#define spin_unlock_wait(lp) do { barrier(); } while(*(volatile unsigned char *)(&(lp)->lock))
+#define __raw_spin_unlock_wait(lock) \
+ do { while (__raw_spin_is_locked(lock)) cpu_relax(); } while (0)
-extern void _do_spin_lock(spinlock_t *lock, char *str);
-extern int _spin_trylock(spinlock_t *lock);
-extern void _do_spin_unlock(spinlock_t *lock);
-
-#define _raw_spin_trylock(lp) _spin_trylock(lp)
-#define _raw_spin_lock(lock) _do_spin_lock(lock, "spin_lock")
-#define _raw_spin_unlock(lock) _do_spin_unlock(lock)
-
-struct _rwlock_debug {
- volatile unsigned int lock;
- unsigned long owner_pc;
- unsigned long reader_pc[NR_CPUS];
-#ifdef CONFIG_PREEMPT
- unsigned int break_lock;
-#endif
-};
-typedef struct _rwlock_debug rwlock_t;
-
-#define RW_LOCK_UNLOCKED (rwlock_t) { 0, 0, {0} }
-
-#define rwlock_init(lp) do { *(lp)= RW_LOCK_UNLOCKED; } while(0)
-
-extern void _do_read_lock(rwlock_t *rw, char *str);
-extern void _do_read_unlock(rwlock_t *rw, char *str);
-extern void _do_write_lock(rwlock_t *rw, char *str);
-extern void _do_write_unlock(rwlock_t *rw);
-
-#define _raw_read_lock(lock) \
-do { unsigned long flags; \
- local_irq_save(flags); \
- _do_read_lock(lock, "read_lock"); \
- local_irq_restore(flags); \
-} while(0)
-
-#define _raw_read_unlock(lock) \
-do { unsigned long flags; \
- local_irq_save(flags); \
- _do_read_unlock(lock, "read_unlock"); \
- local_irq_restore(flags); \
-} while(0)
-
-#define _raw_write_lock(lock) \
-do { unsigned long flags; \
- local_irq_save(flags); \
- _do_write_lock(lock, "write_lock"); \
- local_irq_restore(flags); \
-} while(0)
-
-#define _raw_write_unlock(lock) \
-do { unsigned long flags; \
- local_irq_save(flags); \
- _do_write_unlock(lock); \
- local_irq_restore(flags); \
-} while(0)
-
-#else /* !CONFIG_DEBUG_SPINLOCK */
-
-typedef struct {
- unsigned char lock;
-#ifdef CONFIG_PREEMPT
- unsigned int break_lock;
-#endif
-} spinlock_t;
-
-#define SPIN_LOCK_UNLOCKED (spinlock_t) { 0 }
-
-#define spin_lock_init(lock) (*((unsigned char *)(lock)) = 0)
-#define spin_is_locked(lock) (*((volatile unsigned char *)(lock)) != 0)
-
-#define spin_unlock_wait(lock) \
-do { \
- barrier(); \
-} while(*((volatile unsigned char *)lock))
-
-extern __inline__ void _raw_spin_lock(spinlock_t *lock)
+extern __inline__ void __raw_spin_lock(raw_spinlock_t *lock)
{
__asm__ __volatile__(
"\n1:\n\t"
@@ -121,7 +37,7 @@
: "g2", "memory", "cc");
}
-extern __inline__ int _raw_spin_trylock(spinlock_t *lock)
+extern __inline__ int __raw_spin_trylock(raw_spinlock_t *lock)
{
unsigned int result;
__asm__ __volatile__("ldstub [%1], %0"
@@ -131,7 +47,7 @@
return (result == 0);
}
-extern __inline__ void _raw_spin_unlock(spinlock_t *lock)
+extern __inline__ void __raw_spin_unlock(raw_spinlock_t *lock)
{
__asm__ __volatile__("stb %%g0, [%0]" : : "r" (lock) : "memory");
}
@@ -147,23 +63,11 @@
*
* XXX This might create some problems with my dual spinlock
* XXX scheme, deadlocks etc. -DaveM
- */
-typedef struct {
- volatile unsigned int lock;
-#ifdef CONFIG_PREEMPT
- unsigned int break_lock;
-#endif
-} rwlock_t;
-
-#define RW_LOCK_UNLOCKED (rwlock_t) { 0 }
-
-#define rwlock_init(lp) do { *(lp)= RW_LOCK_UNLOCKED; } while(0)
-
-
-/* Sort of like atomic_t's on Sparc, but even more clever.
+ *
+ * Sort of like atomic_t's on Sparc, but even more clever.
*
* ------------------------------------
- * | 24-bit counter | wlock | rwlock_t
+ * | 24-bit counter | wlock | raw_rwlock_t
* ------------------------------------
* 31 8 7 0
*
@@ -174,9 +78,9 @@
*
* Unfortunately this scheme limits us to ~16,000,000 cpus.
*/
-extern __inline__ void _read_lock(rwlock_t *rw)
+extern __inline__ void __read_lock(raw_rwlock_t *rw)
{
- register rwlock_t *lp asm("g1");
+ register raw_rwlock_t *lp asm("g1");
lp = rw;
__asm__ __volatile__(
"mov %%o7, %%g4\n\t"
@@ -187,16 +91,16 @@
: "g2", "g4", "memory", "cc");
}
-#define _raw_read_lock(lock) \
+#define __raw_read_lock(lock) \
do { unsigned long flags; \
local_irq_save(flags); \
- _read_lock(lock); \
+ __raw_read_lock(lock); \
local_irq_restore(flags); \
} while(0)
-extern __inline__ void _read_unlock(rwlock_t *rw)
+extern __inline__ void __read_unlock(raw_rwlock_t *rw)
{
- register rwlock_t *lp asm("g1");
+ register raw_rwlock_t *lp asm("g1");
lp = rw;
__asm__ __volatile__(
"mov %%o7, %%g4\n\t"
@@ -207,16 +111,16 @@
: "g2", "g4", "memory", "cc");
}
-#define _raw_read_unlock(lock) \
+#define __raw_read_unlock(lock) \
do { unsigned long flags; \
local_irq_save(flags); \
- _read_unlock(lock); \
+ __raw_read_unlock(lock); \
local_irq_restore(flags); \
} while(0)
-extern __inline__ void _raw_write_lock(rwlock_t *rw)
+extern __inline__ void __raw_write_lock(raw_rwlock_t *rw)
{
- register rwlock_t *lp asm("g1");
+ register raw_rwlock_t *lp asm("g1");
lp = rw;
__asm__ __volatile__(
"mov %%o7, %%g4\n\t"
@@ -227,11 +131,9 @@
: "g2", "g4", "memory", "cc");
}
-#define _raw_write_unlock(rw) do { (rw)->lock = 0; } while(0)
+#define __raw_write_unlock(rw) do { (rw)->lock = 0; } while(0)
-#endif /* CONFIG_DEBUG_SPINLOCK */
-
-#define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock)
+#define __raw_spin_lock_flags(lock, flags) __raw_spin_lock(lock)
#endif /* !(__ASSEMBLY__) */
