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authorIngo Molnar <mingo@elte.hu>2005-09-10 00:25:56 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2005-09-10 10:06:21 -0700
commitfb1c8f93d869b34cacb8b8932e2b83d96a19d720 (patch)
treea006d078aa02e421a7dc4793c335308204859d36 /include/asm-s390
parent4327edf6b8a7ac7dce144313947995538842d8fd (diff)
[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>
Diffstat (limited to 'include/asm-s390')
-rw-r--r--include/asm-s390/spinlock.h63
-rw-r--r--include/asm-s390/spinlock_types.h21
2 files changed, 44 insertions, 40 deletions
diff --git a/include/asm-s390/spinlock.h b/include/asm-s390/spinlock.h
index 321b23bba1ec..273dbecf8ace 100644
--- a/include/asm-s390/spinlock.h
+++ b/include/asm-s390/spinlock.h
@@ -27,25 +27,19 @@ _raw_compare_and_swap(volatile unsigned int *lock,
* on the local processor, one does not.
*
* We make no fairness assumptions. They have a cost.
+ *
+ * (the type definitions are in asm/spinlock_types.h)
*/
-typedef struct {
- volatile unsigned int lock;
-#ifdef CONFIG_PREEMPT
- unsigned int break_lock;
-#endif
-} __attribute__ ((aligned (4))) spinlock_t;
-
-#define SPIN_LOCK_UNLOCKED (spinlock_t) { 0 }
-#define spin_lock_init(lp) do { (lp)->lock = 0; } while(0)
-#define spin_unlock_wait(lp) do { barrier(); } while(((volatile spinlock_t *)(lp))->lock)
-#define spin_is_locked(x) ((x)->lock != 0)
-#define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock)
+#define __raw_spin_is_locked(x) ((x)->lock != 0)
+#define __raw_spin_lock_flags(lock, flags) __raw_spin_lock(lock)
+#define __raw_spin_unlock_wait(lock) \
+ do { while (__raw_spin_is_locked(lock)) cpu_relax(); } while (0)
-extern void _raw_spin_lock_wait(spinlock_t *lp, unsigned int pc);
-extern int _raw_spin_trylock_retry(spinlock_t *lp, unsigned int pc);
+extern void _raw_spin_lock_wait(raw_spinlock_t *lp, unsigned int pc);
+extern int _raw_spin_trylock_retry(raw_spinlock_t *lp, unsigned int pc);
-static inline void _raw_spin_lock(spinlock_t *lp)
+static inline void __raw_spin_lock(raw_spinlock_t *lp)
{
unsigned long pc = 1 | (unsigned long) __builtin_return_address(0);
@@ -53,7 +47,7 @@ static inline void _raw_spin_lock(spinlock_t *lp)
_raw_spin_lock_wait(lp, pc);
}
-static inline int _raw_spin_trylock(spinlock_t *lp)
+static inline int __raw_spin_trylock(raw_spinlock_t *lp)
{
unsigned long pc = 1 | (unsigned long) __builtin_return_address(0);
@@ -62,7 +56,7 @@ static inline int _raw_spin_trylock(spinlock_t *lp)
return _raw_spin_trylock_retry(lp, pc);
}
-static inline void _raw_spin_unlock(spinlock_t *lp)
+static inline void __raw_spin_unlock(raw_spinlock_t *lp)
{
_raw_compare_and_swap(&lp->lock, lp->lock, 0);
}
@@ -77,36 +71,25 @@ static inline void _raw_spin_unlock(spinlock_t *lp)
* irq-safe write-lock, but readers can get non-irqsafe
* read-locks.
*/
-typedef struct {
- volatile unsigned int lock;
- volatile unsigned long owner_pc;
-#ifdef CONFIG_PREEMPT
- unsigned int break_lock;
-#endif
-} rwlock_t;
-
-#define RW_LOCK_UNLOCKED (rwlock_t) { 0, 0 }
-
-#define rwlock_init(x) do { *(x) = RW_LOCK_UNLOCKED; } while(0)
/**
* read_can_lock - would read_trylock() succeed?
* @lock: the rwlock in question.
*/
-#define read_can_lock(x) ((int)(x)->lock >= 0)
+#define __raw_read_can_lock(x) ((int)(x)->lock >= 0)
/**
* write_can_lock - would write_trylock() succeed?
* @lock: the rwlock in question.
*/
-#define write_can_lock(x) ((x)->lock == 0)
+#define __raw_write_can_lock(x) ((x)->lock == 0)
-extern void _raw_read_lock_wait(rwlock_t *lp);
-extern int _raw_read_trylock_retry(rwlock_t *lp);
-extern void _raw_write_lock_wait(rwlock_t *lp);
-extern int _raw_write_trylock_retry(rwlock_t *lp);
+extern void _raw_read_lock_wait(raw_rwlock_t *lp);
+extern int _raw_read_trylock_retry(raw_rwlock_t *lp);
+extern void _raw_write_lock_wait(raw_rwlock_t *lp);
+extern int _raw_write_trylock_retry(raw_rwlock_t *lp);
-static inline void _raw_read_lock(rwlock_t *rw)
+static inline void __raw_read_lock(raw_rwlock_t *rw)
{
unsigned int old;
old = rw->lock & 0x7fffffffU;
@@ -114,7 +97,7 @@ static inline void _raw_read_lock(rwlock_t *rw)
_raw_read_lock_wait(rw);
}
-static inline void _raw_read_unlock(rwlock_t *rw)
+static inline void __raw_read_unlock(raw_rwlock_t *rw)
{
unsigned int old, cmp;
@@ -125,18 +108,18 @@ static inline void _raw_read_unlock(rwlock_t *rw)
} while (cmp != old);
}
-static inline void _raw_write_lock(rwlock_t *rw)
+static inline void __raw_write_lock(raw_rwlock_t *rw)
{
if (unlikely(_raw_compare_and_swap(&rw->lock, 0, 0x80000000) != 0))
_raw_write_lock_wait(rw);
}
-static inline void _raw_write_unlock(rwlock_t *rw)
+static inline void __raw_write_unlock(raw_rwlock_t *rw)
{
_raw_compare_and_swap(&rw->lock, 0x80000000, 0);
}
-static inline int _raw_read_trylock(rwlock_t *rw)
+static inline int __raw_read_trylock(raw_rwlock_t *rw)
{
unsigned int old;
old = rw->lock & 0x7fffffffU;
@@ -145,7 +128,7 @@ static inline int _raw_read_trylock(rwlock_t *rw)
return _raw_read_trylock_retry(rw);
}
-static inline int _raw_write_trylock(rwlock_t *rw)
+static inline int __raw_write_trylock(raw_rwlock_t *rw)
{
if (likely(_raw_compare_and_swap(&rw->lock, 0, 0x80000000) == 0))
return 1;
diff --git a/include/asm-s390/spinlock_types.h b/include/asm-s390/spinlock_types.h
new file mode 100644
index 000000000000..f79a2216204f
--- /dev/null
+++ b/include/asm-s390/spinlock_types.h
@@ -0,0 +1,21 @@
+#ifndef __ASM_SPINLOCK_TYPES_H
+#define __ASM_SPINLOCK_TYPES_H
+
+#ifndef __LINUX_SPINLOCK_TYPES_H
+# error "please don't include this file directly"
+#endif
+
+typedef struct {
+ volatile unsigned int lock;
+} __attribute__ ((aligned (4))) raw_spinlock_t;
+
+#define __RAW_SPIN_LOCK_UNLOCKED { 0 }
+
+typedef struct {
+ volatile unsigned int lock;
+ volatile unsigned int owner_pc;
+} raw_rwlock_t;
+
+#define __RAW_RW_LOCK_UNLOCKED { 0, 0 }
+
+#endif