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 --- arch/ppc64/lib/dec_and_lock.c | 8 -------- arch/ppc64/lib/locks.c | 14 +++++++------- 2 files changed, 7 insertions(+), 15 deletions(-) (limited to 'arch/ppc64') diff --git a/arch/ppc64/lib/dec_and_lock.c b/arch/ppc64/lib/dec_and_lock.c index 6e8d859..7b9d4da 100644 --- a/arch/ppc64/lib/dec_and_lock.c +++ b/arch/ppc64/lib/dec_and_lock.c @@ -20,14 +20,7 @@ * has a cmpxchg, and where atomic->value is an int holding * the value of the atomic (i.e. the high bits aren't used * for a lock or anything like that). - * - * N.B. ATOMIC_DEC_AND_LOCK gets defined in include/linux/spinlock.h - * if spinlocks are empty and thus atomic_dec_and_lock is defined - * to be atomic_dec_and_test - in that case we don't need it - * defined here as well. */ - -#ifndef ATOMIC_DEC_AND_LOCK int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock) { int counter; @@ -52,4 +45,3 @@ int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock) } EXPORT_SYMBOL(_atomic_dec_and_lock); -#endif /* ATOMIC_DEC_AND_LOCK */ diff --git a/arch/ppc64/lib/locks.c b/arch/ppc64/lib/locks.c index ef70ef9..033643a 100644 --- a/arch/ppc64/lib/locks.c +++ b/arch/ppc64/lib/locks.c @@ -23,12 +23,12 @@ /* waiting for a spinlock... */ #if defined(CONFIG_PPC_SPLPAR) || defined(CONFIG_PPC_ISERIES) -void __spin_yield(spinlock_t *lock) +void __spin_yield(raw_spinlock_t *lock) { unsigned int lock_value, holder_cpu, yield_count; struct paca_struct *holder_paca; - lock_value = lock->lock; + lock_value = lock->slock; if (lock_value == 0) return; holder_cpu = lock_value & 0xffff; @@ -38,7 +38,7 @@ void __spin_yield(spinlock_t *lock) if ((yield_count & 1) == 0) return; /* virtual cpu is currently running */ rmb(); - if (lock->lock != lock_value) + if (lock->slock != lock_value) return; /* something has changed */ #ifdef CONFIG_PPC_ISERIES HvCall2(HvCallBaseYieldProcessor, HvCall_YieldToProc, @@ -54,7 +54,7 @@ void __spin_yield(spinlock_t *lock) * This turns out to be the same for read and write locks, since * we only know the holder if it is write-locked. */ -void __rw_yield(rwlock_t *rw) +void __rw_yield(raw_rwlock_t *rw) { int lock_value; unsigned int holder_cpu, yield_count; @@ -82,9 +82,9 @@ void __rw_yield(rwlock_t *rw) } #endif -void spin_unlock_wait(spinlock_t *lock) +void __raw_spin_unlock_wait(raw_spinlock_t *lock) { - while (lock->lock) { + while (lock->slock) { HMT_low(); if (SHARED_PROCESSOR) __spin_yield(lock); @@ -92,4 +92,4 @@ void spin_unlock_wait(spinlock_t *lock) HMT_medium(); } -EXPORT_SYMBOL(spin_unlock_wait); +EXPORT_SYMBOL(__raw_spin_unlock_wait); -- cgit v1.1