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![Ingo Molnar](/assets/img/avatar_default.png)
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 <grundler@parisc-linux.org> 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" <tony.luck@intel.com> ia64 fix Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Arjan van de Ven <arjanv@infradead.org> Signed-off-by: Grant Grundler <grundler@parisc-linux.org> Cc: Matthew Wilcox <willy@debian.org> Signed-off-by: Hirokazu Takata <takata@linux-m32r.org> Signed-off-by: Mikael Pettersson <mikpe@csd.uu.se> Signed-off-by: Benoit Boissinot <benoit.boissinot@ens-lyon.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
374 lines
7.9 KiB
C
374 lines
7.9 KiB
C
/*
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* Copyright (2004) Linus Torvalds
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*
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* Author: Zwane Mwaikambo <zwane@fsmlabs.com>
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*
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* Copyright (2004, 2005) Ingo Molnar
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*
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* This file contains the spinlock/rwlock implementations for the
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* SMP and the DEBUG_SPINLOCK cases. (UP-nondebug inlines them)
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*/
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#include <linux/config.h>
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#include <linux/linkage.h>
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#include <linux/preempt.h>
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#include <linux/spinlock.h>
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#include <linux/interrupt.h>
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#include <linux/module.h>
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/*
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* Generic declaration of the raw read_trylock() function,
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* architectures are supposed to optimize this:
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*/
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int __lockfunc generic__raw_read_trylock(raw_rwlock_t *lock)
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{
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__raw_read_lock(lock);
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return 1;
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}
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EXPORT_SYMBOL(generic__raw_read_trylock);
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int __lockfunc _spin_trylock(spinlock_t *lock)
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{
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preempt_disable();
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if (_raw_spin_trylock(lock))
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return 1;
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preempt_enable();
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return 0;
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}
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EXPORT_SYMBOL(_spin_trylock);
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int __lockfunc _read_trylock(rwlock_t *lock)
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{
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preempt_disable();
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if (_raw_read_trylock(lock))
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return 1;
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preempt_enable();
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return 0;
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}
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EXPORT_SYMBOL(_read_trylock);
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int __lockfunc _write_trylock(rwlock_t *lock)
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{
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preempt_disable();
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if (_raw_write_trylock(lock))
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return 1;
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preempt_enable();
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return 0;
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}
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EXPORT_SYMBOL(_write_trylock);
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#if !defined(CONFIG_PREEMPT) || !defined(CONFIG_SMP)
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void __lockfunc _read_lock(rwlock_t *lock)
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{
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preempt_disable();
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_raw_read_lock(lock);
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}
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EXPORT_SYMBOL(_read_lock);
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unsigned long __lockfunc _spin_lock_irqsave(spinlock_t *lock)
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{
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unsigned long flags;
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local_irq_save(flags);
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preempt_disable();
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_raw_spin_lock_flags(lock, &flags);
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return flags;
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}
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EXPORT_SYMBOL(_spin_lock_irqsave);
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void __lockfunc _spin_lock_irq(spinlock_t *lock)
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{
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local_irq_disable();
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preempt_disable();
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_raw_spin_lock(lock);
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}
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EXPORT_SYMBOL(_spin_lock_irq);
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void __lockfunc _spin_lock_bh(spinlock_t *lock)
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{
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local_bh_disable();
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preempt_disable();
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_raw_spin_lock(lock);
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}
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EXPORT_SYMBOL(_spin_lock_bh);
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unsigned long __lockfunc _read_lock_irqsave(rwlock_t *lock)
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{
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unsigned long flags;
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local_irq_save(flags);
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preempt_disable();
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_raw_read_lock(lock);
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return flags;
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}
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EXPORT_SYMBOL(_read_lock_irqsave);
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void __lockfunc _read_lock_irq(rwlock_t *lock)
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{
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local_irq_disable();
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preempt_disable();
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_raw_read_lock(lock);
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}
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EXPORT_SYMBOL(_read_lock_irq);
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void __lockfunc _read_lock_bh(rwlock_t *lock)
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{
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local_bh_disable();
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preempt_disable();
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_raw_read_lock(lock);
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}
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EXPORT_SYMBOL(_read_lock_bh);
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unsigned long __lockfunc _write_lock_irqsave(rwlock_t *lock)
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{
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unsigned long flags;
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local_irq_save(flags);
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preempt_disable();
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_raw_write_lock(lock);
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return flags;
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}
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EXPORT_SYMBOL(_write_lock_irqsave);
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void __lockfunc _write_lock_irq(rwlock_t *lock)
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{
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local_irq_disable();
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preempt_disable();
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_raw_write_lock(lock);
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}
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EXPORT_SYMBOL(_write_lock_irq);
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void __lockfunc _write_lock_bh(rwlock_t *lock)
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{
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local_bh_disable();
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preempt_disable();
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_raw_write_lock(lock);
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}
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EXPORT_SYMBOL(_write_lock_bh);
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void __lockfunc _spin_lock(spinlock_t *lock)
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{
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preempt_disable();
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_raw_spin_lock(lock);
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}
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EXPORT_SYMBOL(_spin_lock);
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void __lockfunc _write_lock(rwlock_t *lock)
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{
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preempt_disable();
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_raw_write_lock(lock);
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}
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EXPORT_SYMBOL(_write_lock);
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#else /* CONFIG_PREEMPT: */
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/*
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* This could be a long-held lock. We both prepare to spin for a long
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* time (making _this_ CPU preemptable if possible), and we also signal
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* towards that other CPU that it should break the lock ASAP.
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*
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* (We do this in a function because inlining it would be excessive.)
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*/
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#define BUILD_LOCK_OPS(op, locktype) \
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void __lockfunc _##op##_lock(locktype##_t *lock) \
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{ \
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preempt_disable(); \
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for (;;) { \
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if (likely(_raw_##op##_trylock(lock))) \
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break; \
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preempt_enable(); \
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if (!(lock)->break_lock) \
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(lock)->break_lock = 1; \
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while (!op##_can_lock(lock) && (lock)->break_lock) \
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cpu_relax(); \
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preempt_disable(); \
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} \
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(lock)->break_lock = 0; \
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} \
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\
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EXPORT_SYMBOL(_##op##_lock); \
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\
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unsigned long __lockfunc _##op##_lock_irqsave(locktype##_t *lock) \
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{ \
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unsigned long flags; \
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\
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preempt_disable(); \
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for (;;) { \
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local_irq_save(flags); \
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if (likely(_raw_##op##_trylock(lock))) \
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break; \
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local_irq_restore(flags); \
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\
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preempt_enable(); \
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if (!(lock)->break_lock) \
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(lock)->break_lock = 1; \
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while (!op##_can_lock(lock) && (lock)->break_lock) \
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cpu_relax(); \
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preempt_disable(); \
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} \
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(lock)->break_lock = 0; \
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return flags; \
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} \
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\
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EXPORT_SYMBOL(_##op##_lock_irqsave); \
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\
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void __lockfunc _##op##_lock_irq(locktype##_t *lock) \
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{ \
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_##op##_lock_irqsave(lock); \
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} \
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\
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EXPORT_SYMBOL(_##op##_lock_irq); \
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\
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void __lockfunc _##op##_lock_bh(locktype##_t *lock) \
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{ \
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unsigned long flags; \
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\
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/* */ \
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/* Careful: we must exclude softirqs too, hence the */ \
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/* irq-disabling. We use the generic preemption-aware */ \
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/* function: */ \
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/**/ \
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flags = _##op##_lock_irqsave(lock); \
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local_bh_disable(); \
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local_irq_restore(flags); \
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} \
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\
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EXPORT_SYMBOL(_##op##_lock_bh)
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/*
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* Build preemption-friendly versions of the following
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* lock-spinning functions:
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*
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* _[spin|read|write]_lock()
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* _[spin|read|write]_lock_irq()
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* _[spin|read|write]_lock_irqsave()
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* _[spin|read|write]_lock_bh()
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*/
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BUILD_LOCK_OPS(spin, spinlock);
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BUILD_LOCK_OPS(read, rwlock);
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BUILD_LOCK_OPS(write, rwlock);
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#endif /* CONFIG_PREEMPT */
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void __lockfunc _spin_unlock(spinlock_t *lock)
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{
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_raw_spin_unlock(lock);
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preempt_enable();
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}
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EXPORT_SYMBOL(_spin_unlock);
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void __lockfunc _write_unlock(rwlock_t *lock)
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{
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_raw_write_unlock(lock);
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preempt_enable();
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}
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EXPORT_SYMBOL(_write_unlock);
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void __lockfunc _read_unlock(rwlock_t *lock)
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{
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_raw_read_unlock(lock);
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preempt_enable();
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}
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EXPORT_SYMBOL(_read_unlock);
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void __lockfunc _spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags)
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{
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_raw_spin_unlock(lock);
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local_irq_restore(flags);
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preempt_enable();
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}
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EXPORT_SYMBOL(_spin_unlock_irqrestore);
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void __lockfunc _spin_unlock_irq(spinlock_t *lock)
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{
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_raw_spin_unlock(lock);
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local_irq_enable();
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preempt_enable();
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}
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EXPORT_SYMBOL(_spin_unlock_irq);
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void __lockfunc _spin_unlock_bh(spinlock_t *lock)
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{
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_raw_spin_unlock(lock);
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preempt_enable_no_resched();
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local_bh_enable();
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}
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EXPORT_SYMBOL(_spin_unlock_bh);
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void __lockfunc _read_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
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{
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_raw_read_unlock(lock);
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local_irq_restore(flags);
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preempt_enable();
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}
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EXPORT_SYMBOL(_read_unlock_irqrestore);
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void __lockfunc _read_unlock_irq(rwlock_t *lock)
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{
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_raw_read_unlock(lock);
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local_irq_enable();
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preempt_enable();
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}
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EXPORT_SYMBOL(_read_unlock_irq);
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void __lockfunc _read_unlock_bh(rwlock_t *lock)
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{
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_raw_read_unlock(lock);
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preempt_enable_no_resched();
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local_bh_enable();
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}
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EXPORT_SYMBOL(_read_unlock_bh);
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void __lockfunc _write_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
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{
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_raw_write_unlock(lock);
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local_irq_restore(flags);
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preempt_enable();
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}
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EXPORT_SYMBOL(_write_unlock_irqrestore);
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void __lockfunc _write_unlock_irq(rwlock_t *lock)
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{
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_raw_write_unlock(lock);
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local_irq_enable();
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preempt_enable();
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}
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EXPORT_SYMBOL(_write_unlock_irq);
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void __lockfunc _write_unlock_bh(rwlock_t *lock)
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{
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_raw_write_unlock(lock);
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preempt_enable_no_resched();
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local_bh_enable();
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}
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EXPORT_SYMBOL(_write_unlock_bh);
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int __lockfunc _spin_trylock_bh(spinlock_t *lock)
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{
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local_bh_disable();
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preempt_disable();
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if (_raw_spin_trylock(lock))
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return 1;
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preempt_enable_no_resched();
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local_bh_enable();
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return 0;
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}
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EXPORT_SYMBOL(_spin_trylock_bh);
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int in_lock_functions(unsigned long addr)
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{
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/* Linker adds these: start and end of __lockfunc functions */
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extern char __lock_text_start[], __lock_text_end[];
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return addr >= (unsigned long)__lock_text_start
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&& addr < (unsigned long)__lock_text_end;
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}
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EXPORT_SYMBOL(in_lock_functions);
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