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-sh/spinlock.h | 61 ++++++++++++++--------------------------- include/asm-sh/spinlock_types.h | 22 +++++++++++++++ 2 files changed, 42 insertions(+), 41 deletions(-) create mode 100644 include/asm-sh/spinlock_types.h (limited to 'include/asm-sh') diff --git a/include/asm-sh/spinlock.h b/include/asm-sh/spinlock.h index e770b55649eb..846322d4c35d 100644 --- a/include/asm-sh/spinlock.h +++ b/include/asm-sh/spinlock.h @@ -15,20 +15,11 @@ /* * Your basic SMP spinlocks, allowing only a single CPU anywhere */ -typedef struct { - volatile unsigned long lock; -#ifdef CONFIG_PREEMPT - unsigned int break_lock; -#endif -} spinlock_t; -#define SPIN_LOCK_UNLOCKED (spinlock_t) { 0 } - -#define spin_lock_init(x) do { *(x) = SPIN_LOCK_UNLOCKED; } while(0) - -#define spin_is_locked(x) ((x)->lock != 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) ((x)->lock != 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)) /* * Simple spin lock operations. There are two variants, one clears IRQ's @@ -36,7 +27,7 @@ typedef struct { * * We make no fairness assumptions. They have a cost. */ -static inline void _raw_spin_lock(spinlock_t *lock) +static inline void __raw_spin_lock(raw_spinlock_t *lock) { __asm__ __volatile__ ( "1:\n\t" @@ -49,14 +40,14 @@ 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) { assert_spin_locked(lock); lock->lock = 0; } -#define _raw_spin_trylock(x) (!test_and_set_bit(0, &(x)->lock)) +#define __raw_spin_trylock(x) (!test_and_set_bit(0, &(x)->lock)) /* * Read-write spinlocks, allowing multiple readers but only one writer. @@ -66,51 +57,40 @@ static inline void _raw_spin_unlock(spinlock_t *lock) * needs to get a irq-safe write-lock, but readers can get non-irqsafe * read-locks. */ -typedef struct { - spinlock_t lock; - atomic_t counter; -#ifdef CONFIG_PREEMPT - unsigned int break_lock; -#endif -} rwlock_t; - -#define RW_LOCK_BIAS 0x01000000 -#define RW_LOCK_UNLOCKED (rwlock_t) { { 0 }, { RW_LOCK_BIAS } } -#define rwlock_init(x) do { *(x) = RW_LOCK_UNLOCKED; } while (0) - -static inline void _raw_read_lock(rwlock_t *rw) + +static inline void __raw_read_lock(raw_rwlock_t *rw) { - _raw_spin_lock(&rw->lock); + __raw_spin_lock(&rw->lock); atomic_inc(&rw->counter); - _raw_spin_unlock(&rw->lock); + __raw_spin_unlock(&rw->lock); } -static inline void _raw_read_unlock(rwlock_t *rw) +static inline void __raw_read_unlock(raw_rwlock_t *rw) { - _raw_spin_lock(&rw->lock); + __raw_spin_lock(&rw->lock); atomic_dec(&rw->counter); - _raw_spin_unlock(&rw->lock); + __raw_spin_unlock(&rw->lock); } -static inline void _raw_write_lock(rwlock_t *rw) +static inline void __raw_write_lock(raw_rwlock_t *rw) { - _raw_spin_lock(&rw->lock); + __raw_spin_lock(&rw->lock); atomic_set(&rw->counter, -1); } -static inline void _raw_write_unlock(rwlock_t *rw) +static inline void __raw_write_unlock(raw_rwlock_t *rw) { atomic_set(&rw->counter, 0); - _raw_spin_unlock(&rw->lock); + __raw_spin_unlock(&rw->lock); } -#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 *rw) +static inline int __raw_write_trylock(raw_rwlock_t *rw) { if (atomic_sub_and_test(RW_LOCK_BIAS, &rw->counter)) return 1; @@ -121,4 +101,3 @@ static inline int _raw_write_trylock(rwlock_t *rw) } #endif /* __ASM_SH_SPINLOCK_H */ - diff --git a/include/asm-sh/spinlock_types.h b/include/asm-sh/spinlock_types.h new file mode 100644 index 000000000000..8c41b6c3aac8 --- /dev/null +++ b/include/asm-sh/spinlock_types.h @@ -0,0 +1,22 @@ +#ifndef __ASM_SH_SPINLOCK_TYPES_H +#define __ASM_SH_SPINLOCK_TYPES_H + +#ifndef __LINUX_SPINLOCK_TYPES_H +# error "please don't include this file directly" +#endif + +typedef struct { + volatile unsigned long lock; +} raw_spinlock_t; + +#define __SPIN_LOCK_UNLOCKED { 0 } + +typedef struct { + raw_spinlock_t lock; + atomic_t counter; +} raw_rwlock_t; + +#define RW_LOCK_BIAS 0x01000000 +#define __RAW_RW_LOCK_UNLOCKED { { 0 }, { RW_LOCK_BIAS } } + +#endif -- cgit v1.2.2