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-parisc/spinlock.h | 163 ++++++++---------------------------------- 1 file changed, 28 insertions(+), 135 deletions(-) (limited to 'include/asm-parisc/spinlock.h') diff --git a/include/asm-parisc/spinlock.h b/include/asm-parisc/spinlock.h index 679ea1c651e..43eaa6e742e 100644 --- a/include/asm-parisc/spinlock.h +++ b/include/asm-parisc/spinlock.h @@ -2,30 +2,25 @@ #define __ASM_SPINLOCK_H #include +#include +#include /* 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 @@ static inline void _raw_spin_lock(spinlock_t *x) 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 @@ static inline void _raw_spin_unlock(spinlock_t *x) 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 @@ static inline int _raw_spin_trylock(spinlock_t *x) 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 @@ static __inline__ void _raw_read_unlock(rwlock_t *rw) * 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 @@ retry: /* 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 @@ static __inline__ int _raw_write_trylock(rwlock_t *rw) 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; } -- cgit v1.2.3