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[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 <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>
This commit is contained in:
Ingo Molnar
committed by
Linus Torvalds
Linus Torvalds
parent
4327edf6b8
commit
fb1c8f93d8
@@ -24,19 +24,19 @@
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# define ATOMIC_HASH_SIZE 4
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# define ATOMIC_HASH(a) (&(__atomic_hash[ (((unsigned long) a)/L1_CACHE_BYTES) & (ATOMIC_HASH_SIZE-1) ]))
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extern spinlock_t __atomic_hash[ATOMIC_HASH_SIZE] __lock_aligned;
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extern raw_spinlock_t __atomic_hash[ATOMIC_HASH_SIZE] __lock_aligned;
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/* Can't use _raw_spin_lock_irq because of #include problems, so
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/* Can't use raw_spin_lock_irq because of #include problems, so
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* this is the substitute */
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#define _atomic_spin_lock_irqsave(l,f) do { \
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spinlock_t *s = ATOMIC_HASH(l); \
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raw_spinlock_t *s = ATOMIC_HASH(l); \
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local_irq_save(f); \
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_raw_spin_lock(s); \
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__raw_spin_lock(s); \
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} while(0)
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#define _atomic_spin_unlock_irqrestore(l,f) do { \
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spinlock_t *s = ATOMIC_HASH(l); \
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_raw_spin_unlock(s); \
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raw_spinlock_t *s = ATOMIC_HASH(l); \
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__raw_spin_unlock(s); \
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local_irq_restore(f); \
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} while(0)
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@@ -2,7 +2,7 @@
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#define _PARISC_BITOPS_H
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#include <linux/compiler.h>
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#include <asm/system.h>
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#include <asm/spinlock.h>
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#include <asm/byteorder.h>
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#include <asm/atomic.h>
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@@ -3,6 +3,7 @@
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#include <linux/config.h>
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#include <linux/mm.h>
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#include <asm/cache.h> /* for flush_user_dcache_range_asm() proto */
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/* The usual comment is "Caches aren't brain-dead on the <architecture>".
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* Unfortunately, that doesn't apply to PA-RISC. */
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@@ -11,6 +11,7 @@
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#ifndef __ASSEMBLY__
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#include <linux/config.h>
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#include <linux/threads.h>
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#include <linux/spinlock_types.h>
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#include <asm/hardware.h>
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#include <asm/page.h>
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+28
-135
@@ -2,30 +2,25 @@
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#define __ASM_SPINLOCK_H
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#include <asm/system.h>
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#include <asm/processor.h>
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#include <asm/spinlock_types.h>
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/* Note that PA-RISC has to use `1' to mean unlocked and `0' to mean locked
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* since it only has load-and-zero. Moreover, at least on some PA processors,
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* the semaphore address has to be 16-byte aligned.
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*/
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#ifndef CONFIG_DEBUG_SPINLOCK
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#define __SPIN_LOCK_UNLOCKED { { 1, 1, 1, 1 } }
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#undef SPIN_LOCK_UNLOCKED
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#define SPIN_LOCK_UNLOCKED (spinlock_t) __SPIN_LOCK_UNLOCKED
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#define spin_lock_init(x) do { *(x) = SPIN_LOCK_UNLOCKED; } while(0)
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static inline int spin_is_locked(spinlock_t *x)
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static inline int __raw_spin_is_locked(raw_spinlock_t *x)
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{
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volatile unsigned int *a = __ldcw_align(x);
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return *a == 0;
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}
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#define spin_unlock_wait(x) do { barrier(); } while(spin_is_locked(x))
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#define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock)
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#define __raw_spin_lock_flags(lock, flags) __raw_spin_lock(lock)
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#define __raw_spin_unlock_wait(x) \
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do { cpu_relax(); } while (__raw_spin_is_locked(x))
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static inline void _raw_spin_lock(spinlock_t *x)
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static inline void __raw_spin_lock(raw_spinlock_t *x)
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{
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volatile unsigned int *a;
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@@ -36,7 +31,7 @@ static inline void _raw_spin_lock(spinlock_t *x)
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mb();
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}
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static inline void _raw_spin_unlock(spinlock_t *x)
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static inline void __raw_spin_unlock(raw_spinlock_t *x)
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{
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volatile unsigned int *a;
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mb();
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@@ -45,7 +40,7 @@ static inline void _raw_spin_unlock(spinlock_t *x)
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mb();
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}
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static inline int _raw_spin_trylock(spinlock_t *x)
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static inline int __raw_spin_trylock(raw_spinlock_t *x)
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{
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volatile unsigned int *a;
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int ret;
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@@ -57,131 +52,38 @@ static inline int _raw_spin_trylock(spinlock_t *x)
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return ret;
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}
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#define spin_lock_own(LOCK, LOCATION) ((void)0)
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#else /* !(CONFIG_DEBUG_SPINLOCK) */
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#define SPINLOCK_MAGIC 0x1D244B3C
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#define __SPIN_LOCK_UNLOCKED { { 1, 1, 1, 1 }, SPINLOCK_MAGIC, 10, __FILE__ , NULL, 0, -1, NULL, NULL }
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#undef SPIN_LOCK_UNLOCKED
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#define SPIN_LOCK_UNLOCKED (spinlock_t) __SPIN_LOCK_UNLOCKED
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#define spin_lock_init(x) do { *(x) = SPIN_LOCK_UNLOCKED; } while(0)
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#define CHECK_LOCK(x) \
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do { \
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if (unlikely((x)->magic != SPINLOCK_MAGIC)) { \
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printk(KERN_ERR "%s:%d: spin_is_locked" \
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" on uninitialized spinlock %p.\n", \
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__FILE__, __LINE__, (x)); \
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} \
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} while(0)
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#define spin_is_locked(x) \
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({ \
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CHECK_LOCK(x); \
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volatile unsigned int *a = __ldcw_align(x); \
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if (unlikely((*a == 0) && (x)->babble)) { \
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(x)->babble--; \
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printk("KERN_WARNING \
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%s:%d: spin_is_locked(%s/%p) already" \
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" locked by %s:%d in %s at %p(%d)\n", \
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__FILE__,__LINE__, (x)->module, (x), \
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(x)->bfile, (x)->bline, (x)->task->comm,\
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(x)->previous, (x)->oncpu); \
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} \
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*a == 0; \
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})
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#define spin_unlock_wait(x) \
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do { \
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CHECK_LOCK(x); \
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volatile unsigned int *a = __ldcw_align(x); \
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if (unlikely((*a == 0) && (x)->babble)) { \
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(x)->babble--; \
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printk("KERN_WARNING \
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%s:%d: spin_unlock_wait(%s/%p)" \
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" owned by %s:%d in %s at %p(%d)\n", \
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__FILE__,__LINE__, (x)->module, (x), \
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(x)->bfile, (x)->bline, (x)->task->comm,\
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(x)->previous, (x)->oncpu); \
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} \
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barrier(); \
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} while (*((volatile unsigned char *)(__ldcw_align(x))) == 0)
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extern void _dbg_spin_lock(spinlock_t *lock, const char *base_file, int line_no);
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extern void _dbg_spin_unlock(spinlock_t *lock, const char *, int);
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extern int _dbg_spin_trylock(spinlock_t * lock, const char *, int);
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#define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock)
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#define _raw_spin_unlock(lock) _dbg_spin_unlock(lock, __FILE__, __LINE__)
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#define _raw_spin_lock(lock) _dbg_spin_lock(lock, __FILE__, __LINE__)
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#define _raw_spin_trylock(lock) _dbg_spin_trylock(lock, __FILE__, __LINE__)
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/* just in case we need it */
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#define spin_lock_own(LOCK, LOCATION) \
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do { \
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volatile unsigned int *a = __ldcw_align(LOCK); \
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if (!((*a == 0) && ((LOCK)->oncpu == smp_processor_id()))) \
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printk("KERN_WARNING \
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%s: called on %d from %p but lock %s on %d\n", \
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LOCATION, smp_processor_id(), \
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__builtin_return_address(0), \
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(*a == 0) ? "taken" : "freed", (LOCK)->on_cpu); \
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} while (0)
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#endif /* !(CONFIG_DEBUG_SPINLOCK) */
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/*
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* Read-write spinlocks, allowing multiple readers
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* but only one writer.
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*/
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typedef struct {
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spinlock_t lock;
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volatile int counter;
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#ifdef CONFIG_PREEMPT
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unsigned int break_lock;
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#endif
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} rwlock_t;
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#define RW_LOCK_UNLOCKED (rwlock_t) { __SPIN_LOCK_UNLOCKED, 0 }
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#define rwlock_init(lp) do { *(lp) = RW_LOCK_UNLOCKED; } while (0)
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#define _raw_read_trylock(lock) generic_raw_read_trylock(lock)
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#define __raw_read_trylock(lock) generic__raw_read_trylock(lock)
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/* read_lock, read_unlock are pretty straightforward. Of course it somehow
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* sucks we end up saving/restoring flags twice for read_lock_irqsave aso. */
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#ifdef CONFIG_DEBUG_RWLOCK
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extern void _dbg_read_lock(rwlock_t * rw, const char *bfile, int bline);
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#define _raw_read_lock(rw) _dbg_read_lock(rw, __FILE__, __LINE__)
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#else
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static __inline__ void _raw_read_lock(rwlock_t *rw)
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static __inline__ void __raw_read_lock(raw_rwlock_t *rw)
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{
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unsigned long flags;
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local_irq_save(flags);
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_raw_spin_lock(&rw->lock);
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__raw_spin_lock(&rw->lock);
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rw->counter++;
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_raw_spin_unlock(&rw->lock);
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__raw_spin_unlock(&rw->lock);
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local_irq_restore(flags);
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}
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#endif /* CONFIG_DEBUG_RWLOCK */
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static __inline__ void _raw_read_unlock(rwlock_t *rw)
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static __inline__ void __raw_read_unlock(raw_rwlock_t *rw)
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{
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unsigned long flags;
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local_irq_save(flags);
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_raw_spin_lock(&rw->lock);
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__raw_spin_lock(&rw->lock);
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rw->counter--;
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_raw_spin_unlock(&rw->lock);
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__raw_spin_unlock(&rw->lock);
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local_irq_restore(flags);
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}
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@@ -194,20 +96,17 @@ static __inline__ void _raw_read_unlock(rwlock_t *rw)
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* writers) in interrupt handlers someone fucked up and we'd dead-lock
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* sooner or later anyway. prumpf */
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#ifdef CONFIG_DEBUG_RWLOCK
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extern void _dbg_write_lock(rwlock_t * rw, const char *bfile, int bline);
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#define _raw_write_lock(rw) _dbg_write_lock(rw, __FILE__, __LINE__)
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#else
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static __inline__ void _raw_write_lock(rwlock_t *rw)
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static __inline__ void __raw_write_lock(raw_rwlock_t *rw)
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{
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retry:
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_raw_spin_lock(&rw->lock);
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__raw_spin_lock(&rw->lock);
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if(rw->counter != 0) {
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/* this basically never happens */
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_raw_spin_unlock(&rw->lock);
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__raw_spin_unlock(&rw->lock);
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while(rw->counter != 0);
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while (rw->counter != 0)
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cpu_relax();
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goto retry;
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}
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@@ -215,26 +114,21 @@ retry:
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/* got it. now leave without unlocking */
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rw->counter = -1; /* remember we are locked */
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}
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#endif /* CONFIG_DEBUG_RWLOCK */
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/* write_unlock is absolutely trivial - we don't have to wait for anything */
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static __inline__ void _raw_write_unlock(rwlock_t *rw)
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static __inline__ void __raw_write_unlock(raw_rwlock_t *rw)
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{
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rw->counter = 0;
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_raw_spin_unlock(&rw->lock);
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__raw_spin_unlock(&rw->lock);
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}
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#ifdef CONFIG_DEBUG_RWLOCK
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extern int _dbg_write_trylock(rwlock_t * rw, const char *bfile, int bline);
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#define _raw_write_trylock(rw) _dbg_write_trylock(rw, __FILE__, __LINE__)
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#else
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static __inline__ int _raw_write_trylock(rwlock_t *rw)
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static __inline__ int __raw_write_trylock(raw_rwlock_t *rw)
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{
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_raw_spin_lock(&rw->lock);
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__raw_spin_lock(&rw->lock);
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if (rw->counter != 0) {
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/* this basically never happens */
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_raw_spin_unlock(&rw->lock);
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__raw_spin_unlock(&rw->lock);
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return 0;
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}
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@@ -243,14 +137,13 @@ static __inline__ int _raw_write_trylock(rwlock_t *rw)
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rw->counter = -1; /* remember we are locked */
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return 1;
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}
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#endif /* CONFIG_DEBUG_RWLOCK */
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static __inline__ int is_read_locked(rwlock_t *rw)
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static __inline__ int __raw_is_read_locked(raw_rwlock_t *rw)
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{
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return rw->counter > 0;
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}
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static __inline__ int is_write_locked(rwlock_t *rw)
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static __inline__ int __raw_is_write_locked(raw_rwlock_t *rw)
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{
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return rw->counter < 0;
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}
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@@ -0,0 +1,21 @@
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#ifndef __ASM_SPINLOCK_TYPES_H
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#define __ASM_SPINLOCK_TYPES_H
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#ifndef __LINUX_SPINLOCK_TYPES_H
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# error "please don't include this file directly"
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#endif
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typedef struct {
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volatile unsigned int lock[4];
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} raw_spinlock_t;
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#define __RAW_SPIN_LOCK_UNLOCKED { { 1, 1, 1, 1 } }
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typedef struct {
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raw_spinlock_t lock;
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volatile int counter;
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} raw_rwlock_t;
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#define __RAW_RW_LOCK_UNLOCKED { __RAW_SPIN_LOCK_UNLOCKED, 0 }
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#endif
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@@ -160,29 +160,7 @@ static inline void set_eiem(unsigned long val)
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})
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#ifdef CONFIG_SMP
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/*
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* Your basic SMP spinlocks, allowing only a single CPU anywhere
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*/
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typedef struct {
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volatile unsigned int lock[4];
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#ifdef CONFIG_DEBUG_SPINLOCK
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unsigned long magic;
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volatile unsigned int babble;
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const char *module;
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char *bfile;
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int bline;
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int oncpu;
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void *previous;
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struct task_struct * task;
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#endif
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#ifdef CONFIG_PREEMPT
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unsigned int break_lock;
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#endif
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} spinlock_t;
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#define __lock_aligned __attribute__((__section__(".data.lock_aligned")))
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# define __lock_aligned __attribute__((__section__(".data.lock_aligned")))
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#endif
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#define KERNEL_START (0x10100000 - 0x1000)
|
||||
|
||||
Reference in New Issue
Block a user