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/sparc/lib/debuglocks.c | 202 -------------------------------------------- 1 file changed, 202 deletions(-) delete mode 100644 arch/sparc/lib/debuglocks.c (limited to 'arch/sparc/lib/debuglocks.c') diff --git a/arch/sparc/lib/debuglocks.c b/arch/sparc/lib/debuglocks.c deleted file mode 100644 index fb182352782c..000000000000 --- a/arch/sparc/lib/debuglocks.c +++ /dev/null @@ -1,202 +0,0 @@ -/* $Id: debuglocks.c,v 1.11 2001/09/20 00:35:31 davem Exp $ - * debuglocks.c: Debugging versions of SMP locking primitives. - * - * Copyright (C) 1997 David S. Miller (davem@caip.rutgers.edu) - * Copyright (C) 1998-99 Anton Blanchard (anton@progsoc.uts.edu.au) - */ - -#include -#include -#include /* For NR_CPUS */ -#include -#include -#include - -#ifdef CONFIG_SMP - -/* Some notes on how these debugging routines work. When a lock is acquired - * an extra debugging member lock->owner_pc is set to the caller of the lock - * acquisition routine. Right before releasing a lock, the debugging program - * counter is cleared to zero. - * - * Furthermore, since PC's are 4 byte aligned on Sparc, we stuff the CPU - * number of the owner in the lowest two bits. - */ - -#define STORE_CALLER(A) __asm__ __volatile__("mov %%i7, %0" : "=r" (A)); - -static inline void show(char *str, spinlock_t *lock, unsigned long caller) -{ - int cpu = smp_processor_id(); - - printk("%s(%p) CPU#%d stuck at %08lx, owner PC(%08lx):CPU(%lx)\n",str, - lock, cpu, caller, lock->owner_pc & ~3, lock->owner_pc & 3); -} - -static inline void show_read(char *str, rwlock_t *lock, unsigned long caller) -{ - int cpu = smp_processor_id(); - - printk("%s(%p) CPU#%d stuck at %08lx, owner PC(%08lx):CPU(%lx)\n", str, - lock, cpu, caller, lock->owner_pc & ~3, lock->owner_pc & 3); -} - -static inline void show_write(char *str, rwlock_t *lock, unsigned long caller) -{ - int cpu = smp_processor_id(); - int i; - - printk("%s(%p) CPU#%d stuck at %08lx, owner PC(%08lx):CPU(%lx)", str, - lock, cpu, caller, lock->owner_pc & ~3, lock->owner_pc & 3); - - for(i = 0; i < NR_CPUS; i++) - printk(" reader[%d]=%08lx", i, lock->reader_pc[i]); - - printk("\n"); -} - -#undef INIT_STUCK -#define INIT_STUCK 100000000 - -void _do_spin_lock(spinlock_t *lock, char *str) -{ - unsigned long caller; - unsigned long val; - int cpu = smp_processor_id(); - int stuck = INIT_STUCK; - - STORE_CALLER(caller); - -again: - __asm__ __volatile__("ldstub [%1], %0" : "=r" (val) : "r" (&(lock->lock))); - if(val) { - while(lock->lock) { - if (!--stuck) { - show(str, lock, caller); - stuck = INIT_STUCK; - } - barrier(); - } - goto again; - } - lock->owner_pc = (cpu & 3) | (caller & ~3); -} - -int _spin_trylock(spinlock_t *lock) -{ - unsigned long val; - unsigned long caller; - int cpu = smp_processor_id(); - - STORE_CALLER(caller); - - __asm__ __volatile__("ldstub [%1], %0" : "=r" (val) : "r" (&(lock->lock))); - if(!val) { - /* We got it, record our identity for debugging. */ - lock->owner_pc = (cpu & 3) | (caller & ~3); - } - return val == 0; -} - -void _do_spin_unlock(spinlock_t *lock) -{ - lock->owner_pc = 0; - barrier(); - lock->lock = 0; -} - -void _do_read_lock(rwlock_t *rw, char *str) -{ - unsigned long caller; - unsigned long val; - int cpu = smp_processor_id(); - int stuck = INIT_STUCK; - - STORE_CALLER(caller); - -wlock_again: - __asm__ __volatile__("ldstub [%1 + 3], %0" : "=r" (val) : "r" (&(rw->lock))); - if(val) { - while(rw->lock & 0xff) { - if (!--stuck) { - show_read(str, rw, caller); - stuck = INIT_STUCK; - } - barrier(); - } - goto wlock_again; - } - - rw->reader_pc[cpu] = caller; - barrier(); - rw->lock++; -} - -void _do_read_unlock(rwlock_t *rw, char *str) -{ - unsigned long caller; - unsigned long val; - int cpu = smp_processor_id(); - int stuck = INIT_STUCK; - - STORE_CALLER(caller); - -wlock_again: - __asm__ __volatile__("ldstub [%1 + 3], %0" : "=r" (val) : "r" (&(rw->lock))); - if(val) { - while(rw->lock & 0xff) { - if (!--stuck) { - show_read(str, rw, caller); - stuck = INIT_STUCK; - } - barrier(); - } - goto wlock_again; - } - - rw->reader_pc[cpu] = 0; - barrier(); - rw->lock -= 0x1ff; -} - -void _do_write_lock(rwlock_t *rw, char *str) -{ - unsigned long caller; - unsigned long val; - int cpu = smp_processor_id(); - int stuck = INIT_STUCK; - - STORE_CALLER(caller); - -wlock_again: - __asm__ __volatile__("ldstub [%1 + 3], %0" : "=r" (val) : "r" (&(rw->lock))); - if(val) { -wlock_wait: - while(rw->lock) { - if (!--stuck) { - show_write(str, rw, caller); - stuck = INIT_STUCK; - } - barrier(); - } - goto wlock_again; - } - - if (rw->lock & ~0xff) { - *(((unsigned char *)&rw->lock)+3) = 0; - barrier(); - goto wlock_wait; - } - - barrier(); - rw->owner_pc = (cpu & 3) | (caller & ~3); -} - -void _do_write_unlock(rwlock_t *rw) -{ - rw->owner_pc = 0; - barrier(); - rw->lock = 0; -} - -#endif /* SMP */ -- cgit v1.2.3