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/alpha/kernel/smp.c | 172 ------------------------------------------------ 1 file changed, 172 deletions(-) (limited to 'arch/alpha/kernel/smp.c') diff --git a/arch/alpha/kernel/smp.c b/arch/alpha/kernel/smp.c index e211aa7404e6..da0be3465791 100644 --- a/arch/alpha/kernel/smp.c +++ b/arch/alpha/kernel/smp.c @@ -989,175 +989,3 @@ flush_icache_user_range(struct vm_area_struct *vma, struct page *page, preempt_enable(); } - -#ifdef CONFIG_DEBUG_SPINLOCK -void -_raw_spin_unlock(spinlock_t * lock) -{ - mb(); - lock->lock = 0; - - lock->on_cpu = -1; - lock->previous = NULL; - lock->task = NULL; - lock->base_file = "none"; - lock->line_no = 0; -} - -void -debug_spin_lock(spinlock_t * lock, const char *base_file, int line_no) -{ - long tmp; - long stuck; - void *inline_pc = __builtin_return_address(0); - unsigned long started = jiffies; - int printed = 0; - int cpu = smp_processor_id(); - - stuck = 1L << 30; - try_again: - - /* Use sub-sections to put the actual loop at the end - of this object file's text section so as to perfect - branch prediction. */ - __asm__ __volatile__( - "1: ldl_l %0,%1\n" - " subq %2,1,%2\n" - " blbs %0,2f\n" - " or %0,1,%0\n" - " stl_c %0,%1\n" - " beq %0,3f\n" - "4: mb\n" - ".subsection 2\n" - "2: ldl %0,%1\n" - " subq %2,1,%2\n" - "3: blt %2,4b\n" - " blbs %0,2b\n" - " br 1b\n" - ".previous" - : "=r" (tmp), "=m" (lock->lock), "=r" (stuck) - : "m" (lock->lock), "2" (stuck) : "memory"); - - if (stuck < 0) { - printk(KERN_WARNING - "%s:%d spinlock stuck in %s at %p(%d)" - " owner %s at %p(%d) %s:%d\n", - base_file, line_no, - current->comm, inline_pc, cpu, - lock->task->comm, lock->previous, - lock->on_cpu, lock->base_file, lock->line_no); - stuck = 1L << 36; - printed = 1; - goto try_again; - } - - /* Exiting. Got the lock. */ - lock->on_cpu = cpu; - lock->previous = inline_pc; - lock->task = current; - lock->base_file = base_file; - lock->line_no = line_no; - - if (printed) { - printk(KERN_WARNING - "%s:%d spinlock grabbed in %s at %p(%d) %ld ticks\n", - base_file, line_no, current->comm, inline_pc, - cpu, jiffies - started); - } -} - -int -debug_spin_trylock(spinlock_t * lock, const char *base_file, int line_no) -{ - int ret; - if ((ret = !test_and_set_bit(0, lock))) { - lock->on_cpu = smp_processor_id(); - lock->previous = __builtin_return_address(0); - lock->task = current; - } else { - lock->base_file = base_file; - lock->line_no = line_no; - } - return ret; -} -#endif /* CONFIG_DEBUG_SPINLOCK */ - -#ifdef CONFIG_DEBUG_RWLOCK -void _raw_write_lock(rwlock_t * lock) -{ - long regx, regy; - int stuck_lock, stuck_reader; - void *inline_pc = __builtin_return_address(0); - - try_again: - - stuck_lock = 1<<30; - stuck_reader = 1<<30; - - __asm__ __volatile__( - "1: ldl_l %1,%0\n" - " blbs %1,6f\n" - " blt %1,8f\n" - " mov 1,%1\n" - " stl_c %1,%0\n" - " beq %1,6f\n" - "4: mb\n" - ".subsection 2\n" - "6: blt %3,4b # debug\n" - " subl %3,1,%3 # debug\n" - " ldl %1,%0\n" - " blbs %1,6b\n" - "8: blt %4,4b # debug\n" - " subl %4,1,%4 # debug\n" - " ldl %1,%0\n" - " blt %1,8b\n" - " br 1b\n" - ".previous" - : "=m" (*(volatile int *)lock), "=&r" (regx), "=&r" (regy), - "=&r" (stuck_lock), "=&r" (stuck_reader) - : "m" (*(volatile int *)lock), "3" (stuck_lock), "4" (stuck_reader) : "memory"); - - if (stuck_lock < 0) { - printk(KERN_WARNING "write_lock stuck at %p\n", inline_pc); - goto try_again; - } - if (stuck_reader < 0) { - printk(KERN_WARNING "write_lock stuck on readers at %p\n", - inline_pc); - goto try_again; - } -} - -void _raw_read_lock(rwlock_t * lock) -{ - long regx; - int stuck_lock; - void *inline_pc = __builtin_return_address(0); - - try_again: - - stuck_lock = 1<<30; - - __asm__ __volatile__( - "1: ldl_l %1,%0;" - " blbs %1,6f;" - " subl %1,2,%1;" - " stl_c %1,%0;" - " beq %1,6f;" - "4: mb\n" - ".subsection 2\n" - "6: ldl %1,%0;" - " blt %2,4b # debug\n" - " subl %2,1,%2 # debug\n" - " blbs %1,6b;" - " br 1b\n" - ".previous" - : "=m" (*(volatile int *)lock), "=&r" (regx), "=&r" (stuck_lock) - : "m" (*(volatile int *)lock), "2" (stuck_lock) : "memory"); - - if (stuck_lock < 0) { - printk(KERN_WARNING "read_lock stuck at %p\n", inline_pc); - goto try_again; - } -} -#endif /* CONFIG_DEBUG_RWLOCK */ -- cgit v1.2.3