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-s390/spinlock.h | 63 ++++++++++++++------------------------- include/asm-s390/spinlock_types.h | 21 +++++++++++++ 2 files changed, 44 insertions(+), 40 deletions(-) create mode 100644 include/asm-s390/spinlock_types.h (limited to 'include/asm-s390') diff --git a/include/asm-s390/spinlock.h b/include/asm-s390/spinlock.h index 321b23bba1ec..273dbecf8ace 100644 --- a/include/asm-s390/spinlock.h +++ b/include/asm-s390/spinlock.h @@ -27,25 +27,19 @@ _raw_compare_and_swap(volatile unsigned int *lock, * on the local processor, one does not. * * We make no fairness assumptions. They have a cost. + * + * (the type definitions are in asm/spinlock_types.h) */ -typedef struct { - volatile unsigned int lock; -#ifdef CONFIG_PREEMPT - unsigned int break_lock; -#endif -} __attribute__ ((aligned (4))) spinlock_t; - -#define SPIN_LOCK_UNLOCKED (spinlock_t) { 0 } -#define spin_lock_init(lp) do { (lp)->lock = 0; } while(0) -#define spin_unlock_wait(lp) do { barrier(); } while(((volatile spinlock_t *)(lp))->lock) -#define spin_is_locked(x) ((x)->lock != 0) -#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(lock) \ + do { while (__raw_spin_is_locked(lock)) cpu_relax(); } while (0) -extern void _raw_spin_lock_wait(spinlock_t *lp, unsigned int pc); -extern int _raw_spin_trylock_retry(spinlock_t *lp, unsigned int pc); +extern void _raw_spin_lock_wait(raw_spinlock_t *lp, unsigned int pc); +extern int _raw_spin_trylock_retry(raw_spinlock_t *lp, unsigned int pc); -static inline void _raw_spin_lock(spinlock_t *lp) +static inline void __raw_spin_lock(raw_spinlock_t *lp) { unsigned long pc = 1 | (unsigned long) __builtin_return_address(0); @@ -53,7 +47,7 @@ static inline void _raw_spin_lock(spinlock_t *lp) _raw_spin_lock_wait(lp, pc); } -static inline int _raw_spin_trylock(spinlock_t *lp) +static inline int __raw_spin_trylock(raw_spinlock_t *lp) { unsigned long pc = 1 | (unsigned long) __builtin_return_address(0); @@ -62,7 +56,7 @@ static inline int _raw_spin_trylock(spinlock_t *lp) return _raw_spin_trylock_retry(lp, pc); } -static inline void _raw_spin_unlock(spinlock_t *lp) +static inline void __raw_spin_unlock(raw_spinlock_t *lp) { _raw_compare_and_swap(&lp->lock, lp->lock, 0); } @@ -77,36 +71,25 @@ static inline void _raw_spin_unlock(spinlock_t *lp) * irq-safe write-lock, but readers can get non-irqsafe * read-locks. */ -typedef struct { - volatile unsigned int lock; - volatile unsigned long owner_pc; -#ifdef CONFIG_PREEMPT - unsigned int break_lock; -#endif -} rwlock_t; - -#define RW_LOCK_UNLOCKED (rwlock_t) { 0, 0 } - -#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 == 0) +#define __raw_write_can_lock(x) ((x)->lock == 0) -extern void _raw_read_lock_wait(rwlock_t *lp); -extern int _raw_read_trylock_retry(rwlock_t *lp); -extern void _raw_write_lock_wait(rwlock_t *lp); -extern int _raw_write_trylock_retry(rwlock_t *lp); +extern void _raw_read_lock_wait(raw_rwlock_t *lp); +extern int _raw_read_trylock_retry(raw_rwlock_t *lp); +extern void _raw_write_lock_wait(raw_rwlock_t *lp); +extern int _raw_write_trylock_retry(raw_rwlock_t *lp); -static inline void _raw_read_lock(rwlock_t *rw) +static inline void __raw_read_lock(raw_rwlock_t *rw) { unsigned int old; old = rw->lock & 0x7fffffffU; @@ -114,7 +97,7 @@ static inline void _raw_read_lock(rwlock_t *rw) _raw_read_lock_wait(rw); } -static inline void _raw_read_unlock(rwlock_t *rw) +static inline void __raw_read_unlock(raw_rwlock_t *rw) { unsigned int old, cmp; @@ -125,18 +108,18 @@ static inline void _raw_read_unlock(rwlock_t *rw) } while (cmp != old); } -static inline void _raw_write_lock(rwlock_t *rw) +static inline void __raw_write_lock(raw_rwlock_t *rw) { if (unlikely(_raw_compare_and_swap(&rw->lock, 0, 0x80000000) != 0)) _raw_write_lock_wait(rw); } -static inline void _raw_write_unlock(rwlock_t *rw) +static inline void __raw_write_unlock(raw_rwlock_t *rw) { _raw_compare_and_swap(&rw->lock, 0x80000000, 0); } -static inline int _raw_read_trylock(rwlock_t *rw) +static inline int __raw_read_trylock(raw_rwlock_t *rw) { unsigned int old; old = rw->lock & 0x7fffffffU; @@ -145,7 +128,7 @@ static inline int _raw_read_trylock(rwlock_t *rw) return _raw_read_trylock_retry(rw); } -static inline int _raw_write_trylock(rwlock_t *rw) +static inline int __raw_write_trylock(raw_rwlock_t *rw) { if (likely(_raw_compare_and_swap(&rw->lock, 0, 0x80000000) == 0)) return 1; diff --git a/include/asm-s390/spinlock_types.h b/include/asm-s390/spinlock_types.h new file mode 100644 index 000000000000..f79a2216204f --- /dev/null +++ b/include/asm-s390/spinlock_types.h @@ -0,0 +1,21 @@ +#ifndef __ASM_SPINLOCK_TYPES_H +#define __ASM_SPINLOCK_TYPES_H + +#ifndef __LINUX_SPINLOCK_TYPES_H +# error "please don't include this file directly" +#endif + +typedef struct { + volatile unsigned int lock; +} __attribute__ ((aligned (4))) raw_spinlock_t; + +#define __RAW_SPIN_LOCK_UNLOCKED { 0 } + +typedef struct { + volatile unsigned int lock; + volatile unsigned int owner_pc; +} raw_rwlock_t; + +#define __RAW_RW_LOCK_UNLOCKED { 0, 0 } + +#endif -- cgit v1.2.3