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/sparc64/lib/Makefile | 1 - arch/sparc64/lib/debuglocks.c | 366 ------------------------------------------ 2 files changed, 367 deletions(-) delete mode 100644 arch/sparc64/lib/debuglocks.c (limited to 'arch/sparc64/lib') diff --git a/arch/sparc64/lib/Makefile b/arch/sparc64/lib/Makefile index 40dbeec..d968aeb 100644 --- a/arch/sparc64/lib/Makefile +++ b/arch/sparc64/lib/Makefile @@ -14,7 +14,6 @@ lib-y := PeeCeeI.o copy_page.o clear_page.o strlen.o strncmp.o \ copy_in_user.o user_fixup.o memmove.o \ mcount.o ipcsum.o rwsem.o xor.o find_bit.o delay.o -lib-$(CONFIG_DEBUG_SPINLOCK) += debuglocks.o lib-$(CONFIG_HAVE_DEC_LOCK) += dec_and_lock.o obj-y += iomap.o diff --git a/arch/sparc64/lib/debuglocks.c b/arch/sparc64/lib/debuglocks.c deleted file mode 100644 index f5f0b55..0000000 --- a/arch/sparc64/lib/debuglocks.c +++ /dev/null @@ -1,366 +0,0 @@ -/* $Id: debuglocks.c,v 1.9 2001/11/17 00:10:48 davem Exp $ - * debuglocks.c: Debugging versions of SMP locking primitives. - * - * Copyright (C) 1998 David S. Miller (davem@redhat.com) - */ - -#include -#include -#include -#include -#include - -#ifdef CONFIG_SMP - -static inline void show (char *str, spinlock_t *lock, unsigned long caller) -{ - int cpu = smp_processor_id(); - - printk("%s(%p) CPU#%d stuck at %08x, owner PC(%08x):CPU(%x)\n", - str, lock, cpu, (unsigned int) caller, - lock->owner_pc, lock->owner_cpu); -} - -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 %08x, writer PC(%08x):CPU(%x)\n", - str, lock, cpu, (unsigned int) caller, - lock->writer_pc, lock->writer_cpu); -} - -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 %08x\n", - str, lock, cpu, (unsigned int) caller); - printk("Writer: PC(%08x):CPU(%x)\n", - lock->writer_pc, lock->writer_cpu); - printk("Readers:"); - for (i = 0; i < NR_CPUS; i++) - if (lock->reader_pc[i]) - printk(" %d[%08x]", 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 stuck = INIT_STUCK; - int cpu = get_cpu(); - int shown = 0; - -again: - __asm__ __volatile__("ldstub [%1], %0" - : "=r" (val) - : "r" (&(lock->lock)) - : "memory"); - membar_storeload_storestore(); - if (val) { - while (lock->lock) { - if (!--stuck) { - if (shown++ <= 2) - show(str, lock, caller); - stuck = INIT_STUCK; - } - rmb(); - } - goto again; - } - lock->owner_pc = ((unsigned int)caller); - lock->owner_cpu = cpu; - current->thread.smp_lock_count++; - current->thread.smp_lock_pc = ((unsigned int)caller); - - put_cpu(); -} - -int _do_spin_trylock(spinlock_t *lock, unsigned long caller) -{ - unsigned long val; - int cpu = get_cpu(); - - __asm__ __volatile__("ldstub [%1], %0" - : "=r" (val) - : "r" (&(lock->lock)) - : "memory"); - membar_storeload_storestore(); - if (!val) { - lock->owner_pc = ((unsigned int)caller); - lock->owner_cpu = cpu; - current->thread.smp_lock_count++; - current->thread.smp_lock_pc = ((unsigned int)caller); - } - - put_cpu(); - - return val == 0; -} - -void _do_spin_unlock(spinlock_t *lock) -{ - lock->owner_pc = 0; - lock->owner_cpu = NO_PROC_ID; - membar_storestore_loadstore(); - lock->lock = 0; - current->thread.smp_lock_count--; -} - -/* Keep INIT_STUCK the same... */ - -void _do_read_lock(rwlock_t *rw, char *str, unsigned long caller) -{ - unsigned long val; - int stuck = INIT_STUCK; - int cpu = get_cpu(); - int shown = 0; - -wlock_again: - /* Wait for any writer to go away. */ - while (((long)(rw->lock)) < 0) { - if (!--stuck) { - if (shown++ <= 2) - show_read(str, rw, caller); - stuck = INIT_STUCK; - } - rmb(); - } - /* Try once to increment the counter. */ - __asm__ __volatile__( -" ldx [%0], %%g1\n" -" brlz,a,pn %%g1, 2f\n" -" mov 1, %0\n" -" add %%g1, 1, %%g7\n" -" casx [%0], %%g1, %%g7\n" -" sub %%g1, %%g7, %0\n" -"2:" : "=r" (val) - : "0" (&(rw->lock)) - : "g1", "g7", "memory"); - membar_storeload_storestore(); - if (val) - goto wlock_again; - rw->reader_pc[cpu] = ((unsigned int)caller); - current->thread.smp_lock_count++; - current->thread.smp_lock_pc = ((unsigned int)caller); - - put_cpu(); -} - -void _do_read_unlock(rwlock_t *rw, char *str, unsigned long caller) -{ - unsigned long val; - int stuck = INIT_STUCK; - int cpu = get_cpu(); - int shown = 0; - - /* Drop our identity _first_. */ - rw->reader_pc[cpu] = 0; - current->thread.smp_lock_count--; -runlock_again: - /* Spin trying to decrement the counter using casx. */ - __asm__ __volatile__( -" membar #StoreLoad | #LoadLoad\n" -" ldx [%0], %%g1\n" -" sub %%g1, 1, %%g7\n" -" casx [%0], %%g1, %%g7\n" -" membar #StoreLoad | #StoreStore\n" -" sub %%g1, %%g7, %0\n" - : "=r" (val) - : "0" (&(rw->lock)) - : "g1", "g7", "memory"); - if (val) { - if (!--stuck) { - if (shown++ <= 2) - show_read(str, rw, caller); - stuck = INIT_STUCK; - } - goto runlock_again; - } - - put_cpu(); -} - -void _do_write_lock(rwlock_t *rw, char *str, unsigned long caller) -{ - unsigned long val; - int stuck = INIT_STUCK; - int cpu = get_cpu(); - int shown = 0; - -wlock_again: - /* Spin while there is another writer. */ - while (((long)rw->lock) < 0) { - if (!--stuck) { - if (shown++ <= 2) - show_write(str, rw, caller); - stuck = INIT_STUCK; - } - rmb(); - } - - /* Try to acuire the write bit. */ - __asm__ __volatile__( -" mov 1, %%g3\n" -" sllx %%g3, 63, %%g3\n" -" ldx [%0], %%g1\n" -" brlz,pn %%g1, 1f\n" -" or %%g1, %%g3, %%g7\n" -" casx [%0], %%g1, %%g7\n" -" membar #StoreLoad | #StoreStore\n" -" ba,pt %%xcc, 2f\n" -" sub %%g1, %%g7, %0\n" -"1: mov 1, %0\n" -"2:" : "=r" (val) - : "0" (&(rw->lock)) - : "g3", "g1", "g7", "memory"); - if (val) { - /* We couldn't get the write bit. */ - if (!--stuck) { - if (shown++ <= 2) - show_write(str, rw, caller); - stuck = INIT_STUCK; - } - goto wlock_again; - } - if ((rw->lock & ((1UL<<63)-1UL)) != 0UL) { - /* Readers still around, drop the write - * lock, spin, and try again. - */ - if (!--stuck) { - if (shown++ <= 2) - show_write(str, rw, caller); - stuck = INIT_STUCK; - } - __asm__ __volatile__( -" mov 1, %%g3\n" -" sllx %%g3, 63, %%g3\n" -"1: ldx [%0], %%g1\n" -" andn %%g1, %%g3, %%g7\n" -" casx [%0], %%g1, %%g7\n" -" cmp %%g1, %%g7\n" -" membar #StoreLoad | #StoreStore\n" -" bne,pn %%xcc, 1b\n" -" nop" - : /* no outputs */ - : "r" (&(rw->lock)) - : "g3", "g1", "g7", "cc", "memory"); - while(rw->lock != 0) { - if (!--stuck) { - if (shown++ <= 2) - show_write(str, rw, caller); - stuck = INIT_STUCK; - } - rmb(); - } - goto wlock_again; - } - - /* We have it, say who we are. */ - rw->writer_pc = ((unsigned int)caller); - rw->writer_cpu = cpu; - current->thread.smp_lock_count++; - current->thread.smp_lock_pc = ((unsigned int)caller); - - put_cpu(); -} - -void _do_write_unlock(rwlock_t *rw, unsigned long caller) -{ - unsigned long val; - int stuck = INIT_STUCK; - int shown = 0; - - /* Drop our identity _first_ */ - rw->writer_pc = 0; - rw->writer_cpu = NO_PROC_ID; - current->thread.smp_lock_count--; -wlock_again: - __asm__ __volatile__( -" membar #StoreLoad | #LoadLoad\n" -" mov 1, %%g3\n" -" sllx %%g3, 63, %%g3\n" -" ldx [%0], %%g1\n" -" andn %%g1, %%g3, %%g7\n" -" casx [%0], %%g1, %%g7\n" -" membar #StoreLoad | #StoreStore\n" -" sub %%g1, %%g7, %0\n" - : "=r" (val) - : "0" (&(rw->lock)) - : "g3", "g1", "g7", "memory"); - if (val) { - if (!--stuck) { - if (shown++ <= 2) - show_write("write_unlock", rw, caller); - stuck = INIT_STUCK; - } - goto wlock_again; - } -} - -int _do_write_trylock(rwlock_t *rw, char *str, unsigned long caller) -{ - unsigned long val; - int cpu = get_cpu(); - - /* Try to acuire the write bit. */ - __asm__ __volatile__( -" mov 1, %%g3\n" -" sllx %%g3, 63, %%g3\n" -" ldx [%0], %%g1\n" -" brlz,pn %%g1, 1f\n" -" or %%g1, %%g3, %%g7\n" -" casx [%0], %%g1, %%g7\n" -" membar #StoreLoad | #StoreStore\n" -" ba,pt %%xcc, 2f\n" -" sub %%g1, %%g7, %0\n" -"1: mov 1, %0\n" -"2:" : "=r" (val) - : "0" (&(rw->lock)) - : "g3", "g1", "g7", "memory"); - - if (val) { - put_cpu(); - return 0; - } - - if ((rw->lock & ((1UL<<63)-1UL)) != 0UL) { - /* Readers still around, drop the write - * lock, return failure. - */ - __asm__ __volatile__( -" mov 1, %%g3\n" -" sllx %%g3, 63, %%g3\n" -"1: ldx [%0], %%g1\n" -" andn %%g1, %%g3, %%g7\n" -" casx [%0], %%g1, %%g7\n" -" cmp %%g1, %%g7\n" -" membar #StoreLoad | #StoreStore\n" -" bne,pn %%xcc, 1b\n" -" nop" - : /* no outputs */ - : "r" (&(rw->lock)) - : "g3", "g1", "g7", "cc", "memory"); - - put_cpu(); - - return 0; - } - - /* We have it, say who we are. */ - rw->writer_pc = ((unsigned int)caller); - rw->writer_cpu = cpu; - current->thread.smp_lock_count++; - current->thread.smp_lock_pc = ((unsigned int)caller); - - put_cpu(); - - return 1; -} - -#endif /* CONFIG_SMP */ -- cgit v1.1