From fb1c8f93d869b34cacb8b8932e2b83d96a19d720 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Sat, 10 Sep 2005 00:25:56 -0700 Subject: [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 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" ia64 fix Signed-off-by: Ingo Molnar Signed-off-by: Arjan van de Ven Signed-off-by: Grant Grundler Cc: Matthew Wilcox Signed-off-by: Hirokazu Takata Signed-off-by: Mikael Pettersson Signed-off-by: Benoit Boissinot Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/asm-m32r/spinlock.h | 127 +++++++++----------------------------- include/asm-m32r/spinlock_types.h | 23 +++++++ 2 files changed, 53 insertions(+), 97 deletions(-) create mode 100644 include/asm-m32r/spinlock_types.h (limited to 'include/asm-m32r') diff --git a/include/asm-m32r/spinlock.h b/include/asm-m32r/spinlock.h index 6608d8371c50..7de7def28da9 100644 --- a/include/asm-m32r/spinlock.h +++ b/include/asm-m32r/spinlock.h @@ -14,57 +14,30 @@ #include #include -extern int printk(const char * fmt, ...) - __attribute__ ((format (printf, 1, 2))); - -#define RW_LOCK_BIAS 0x01000000 -#define RW_LOCK_BIAS_STR "0x01000000" - /* * Your basic SMP spinlocks, allowing only a single CPU anywhere - */ - -typedef struct { - volatile int slock; -#ifdef CONFIG_DEBUG_SPINLOCK - unsigned magic; -#endif -#ifdef CONFIG_PREEMPT - unsigned int break_lock; -#endif -} spinlock_t; - -#define SPINLOCK_MAGIC 0xdead4ead - -#ifdef CONFIG_DEBUG_SPINLOCK -#define SPINLOCK_MAGIC_INIT , SPINLOCK_MAGIC -#else -#define SPINLOCK_MAGIC_INIT /* */ -#endif - -#define SPIN_LOCK_UNLOCKED (spinlock_t) { 1 SPINLOCK_MAGIC_INIT } - -#define spin_lock_init(x) do { *(x) = SPIN_LOCK_UNLOCKED; } while(0) - -/* + * + * (the type definitions are in asm/spinlock_types.h) + * * Simple spin lock operations. There are two variants, one clears IRQ's * on the local processor, one does not. * * We make no fairness assumptions. They have a cost. */ -#define spin_is_locked(x) (*(volatile int *)(&(x)->slock) <= 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_is_locked(x) (*(volatile int *)(&(x)->slock) <= 0) +#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)) /** - * _raw_spin_trylock - Try spin lock and return a result + * __raw_spin_trylock - Try spin lock and return a result * @lock: Pointer to the lock variable * - * _raw_spin_trylock() tries to get the lock and returns a result. + * __raw_spin_trylock() tries to get the lock and returns a result. * On the m32r, the result value is 1 (= Success) or 0 (= Failure). */ -static inline int _raw_spin_trylock(spinlock_t *lock) +static inline int __raw_spin_trylock(raw_spinlock_t *lock) { int oldval; unsigned long tmp1, tmp2; @@ -78,7 +51,7 @@ static inline int _raw_spin_trylock(spinlock_t *lock) * } */ __asm__ __volatile__ ( - "# spin_trylock \n\t" + "# __raw_spin_trylock \n\t" "ldi %1, #0; \n\t" "mvfc %2, psw; \n\t" "clrpsw #0x40 -> nop; \n\t" @@ -97,16 +70,10 @@ static inline int _raw_spin_trylock(spinlock_t *lock) return (oldval > 0); } -static inline void _raw_spin_lock(spinlock_t *lock) +static inline void __raw_spin_lock(raw_spinlock_t *lock) { unsigned long tmp0, tmp1; -#ifdef CONFIG_DEBUG_SPINLOCK - if (unlikely(lock->magic != SPINLOCK_MAGIC)) { - printk("pc: %p\n", __builtin_return_address(0)); - BUG(); - } -#endif /* * lock->slock : =1 : unlock * : <=0 : lock @@ -118,7 +85,7 @@ static inline void _raw_spin_lock(spinlock_t *lock) * } */ __asm__ __volatile__ ( - "# spin_lock \n\t" + "# __raw_spin_lock \n\t" ".fillinsn \n" "1: \n\t" "mvfc %1, psw; \n\t" @@ -145,12 +112,8 @@ static inline void _raw_spin_lock(spinlock_t *lock) ); } -static inline void _raw_spin_unlock(spinlock_t *lock) +static inline void __raw_spin_unlock(raw_spinlock_t *lock) { -#ifdef CONFIG_DEBUG_SPINLOCK - BUG_ON(lock->magic != SPINLOCK_MAGIC); - BUG_ON(!spin_is_locked(lock)); -#endif mb(); lock->slock = 1; } @@ -164,59 +127,32 @@ static inline void _raw_spin_unlock(spinlock_t *lock) * can "mix" irq-safe locks - any writer needs to get a * irq-safe write-lock, but readers can get non-irqsafe * read-locks. + * + * On x86, we implement read-write locks as a 32-bit counter + * with the high bit (sign) being the "contended" bit. + * + * The inline assembly is non-obvious. Think about it. + * + * Changed to use the same technique as rw semaphores. See + * semaphore.h for details. -ben */ -typedef struct { - volatile int lock; -#ifdef CONFIG_DEBUG_SPINLOCK - unsigned magic; -#endif -#ifdef CONFIG_PREEMPT - unsigned int break_lock; -#endif -} rwlock_t; - -#define RWLOCK_MAGIC 0xdeaf1eed - -#ifdef CONFIG_DEBUG_SPINLOCK -#define RWLOCK_MAGIC_INIT , RWLOCK_MAGIC -#else -#define RWLOCK_MAGIC_INIT /* */ -#endif - -#define RW_LOCK_UNLOCKED (rwlock_t) { RW_LOCK_BIAS RWLOCK_MAGIC_INIT } - -#define rwlock_init(x) do { *(x) = RW_LOCK_UNLOCKED; } while(0) /** * read_can_lock - would read_trylock() succeed? * @lock: the rwlock in question. */ -#define read_can_lock(x) ((int)(x)->lock > 0) +#define __raw_read_can_lock(x) ((int)(x)->lock > 0) /** * write_can_lock - would write_trylock() succeed? * @lock: the rwlock in question. */ -#define write_can_lock(x) ((x)->lock == RW_LOCK_BIAS) - -/* - * On x86, we implement read-write locks as a 32-bit counter - * with the high bit (sign) being the "contended" bit. - * - * The inline assembly is non-obvious. Think about it. - * - * Changed to use the same technique as rw semaphores. See - * semaphore.h for details. -ben - */ -/* the spinlock helpers are in arch/i386/kernel/semaphore.c */ +#define __raw_write_can_lock(x) ((x)->lock == RW_LOCK_BIAS) -static inline void _raw_read_lock(rwlock_t *rw) +static inline void __raw_read_lock(raw_rwlock_t *rw) { unsigned long tmp0, tmp1; -#ifdef CONFIG_DEBUG_SPINLOCK - BUG_ON(rw->magic != RWLOCK_MAGIC); -#endif /* * rw->lock : >0 : unlock * : <=0 : lock @@ -264,13 +200,10 @@ static inline void _raw_read_lock(rwlock_t *rw) ); } -static inline void _raw_write_lock(rwlock_t *rw) +static inline void __raw_write_lock(raw_rwlock_t *rw) { unsigned long tmp0, tmp1, tmp2; -#ifdef CONFIG_DEBUG_SPINLOCK - BUG_ON(rw->magic != RWLOCK_MAGIC); -#endif /* * rw->lock : =RW_LOCK_BIAS_STR : unlock * : !=RW_LOCK_BIAS_STR : lock @@ -320,7 +253,7 @@ static inline void _raw_write_lock(rwlock_t *rw) ); } -static inline void _raw_read_unlock(rwlock_t *rw) +static inline void __raw_read_unlock(raw_rwlock_t *rw) { unsigned long tmp0, tmp1; @@ -342,7 +275,7 @@ static inline void _raw_read_unlock(rwlock_t *rw) ); } -static inline void _raw_write_unlock(rwlock_t *rw) +static inline void __raw_write_unlock(raw_rwlock_t *rw) { unsigned long tmp0, tmp1, tmp2; @@ -366,9 +299,9 @@ static inline void _raw_write_unlock(rwlock_t *rw) ); } -#define _raw_read_trylock(lock) generic_raw_read_trylock(lock) +#define __raw_read_trylock(lock) generic__raw_read_trylock(lock) -static inline int _raw_write_trylock(rwlock_t *lock) +static inline int __raw_write_trylock(raw_rwlock_t *lock) { atomic_t *count = (atomic_t *)lock; if (atomic_sub_and_test(RW_LOCK_BIAS, count)) diff --git a/include/asm-m32r/spinlock_types.h b/include/asm-m32r/spinlock_types.h new file mode 100644 index 000000000000..7e9941c45f40 --- /dev/null +++ b/include/asm-m32r/spinlock_types.h @@ -0,0 +1,23 @@ +#ifndef _ASM_M32R_SPINLOCK_TYPES_H +#define _ASM_M32R_SPINLOCK_TYPES_H + +#ifndef __LINUX_SPINLOCK_TYPES_H +# error "please don't include this file directly" +#endif + +typedef struct { + volatile int slock; +} raw_spinlock_t; + +#define __RAW_SPIN_LOCK_UNLOCKED { 1 } + +typedef struct { + volatile int lock; +} raw_rwlock_t; + +#define RW_LOCK_BIAS 0x01000000 +#define RW_LOCK_BIAS_STR "0x01000000" + +#define __RAW_RW_LOCK_UNLOCKED { RW_LOCK_BIAS } + +#endif -- cgit v1.2.3-59-g8ed1b