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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 /kernel
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 'kernel')
-rw-r--r--kernel/Makefile1
-rw-r--r--kernel/sched.c4
-rw-r--r--kernel/spinlock.c15
3 files changed, 14 insertions, 6 deletions
diff --git a/kernel/Makefile b/kernel/Makefile
index 8d57a2f1226b..ff4dc02ce170 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -12,6 +12,7 @@ obj-y = sched.o fork.o exec_domain.o panic.o printk.o profile.o \
obj-$(CONFIG_FUTEX) += futex.o
obj-$(CONFIG_GENERIC_ISA_DMA) += dma.o
obj-$(CONFIG_SMP) += cpu.o spinlock.o
+obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock.o
obj-$(CONFIG_UID16) += uid16.o
obj-$(CONFIG_MODULES) += module.o
obj-$(CONFIG_KALLSYMS) += kallsyms.o
diff --git a/kernel/sched.c b/kernel/sched.c
index 2632b812cf24..15db82116e19 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -1511,6 +1511,10 @@ static inline void finish_task_switch(runqueue_t *rq, task_t *prev)
* Manfred Spraul <manfred@colorfullife.com>
*/
prev_task_flags = prev->flags;
+#ifdef CONFIG_DEBUG_SPINLOCK
+ /* this is a valid case when another task releases the spinlock */
+ rq->lock.owner = current;
+#endif
finish_arch_switch(prev);
finish_lock_switch(rq, prev);
if (mm)
diff --git a/kernel/spinlock.c b/kernel/spinlock.c
index 0c3f9d8bbe17..0375fcd5921d 100644
--- a/kernel/spinlock.c
+++ b/kernel/spinlock.c
@@ -3,7 +3,10 @@
*
* Author: Zwane Mwaikambo <zwane@fsmlabs.com>
*
- * Copyright (2004) Ingo Molnar
+ * Copyright (2004, 2005) Ingo Molnar
+ *
+ * This file contains the spinlock/rwlock implementations for the
+ * SMP and the DEBUG_SPINLOCK cases. (UP-nondebug inlines them)
*/
#include <linux/config.h>
@@ -17,12 +20,12 @@
* Generic declaration of the raw read_trylock() function,
* architectures are supposed to optimize this:
*/
-int __lockfunc generic_raw_read_trylock(rwlock_t *lock)
+int __lockfunc generic__raw_read_trylock(raw_rwlock_t *lock)
{
- _raw_read_lock(lock);
+ __raw_read_lock(lock);
return 1;
}
-EXPORT_SYMBOL(generic_raw_read_trylock);
+EXPORT_SYMBOL(generic__raw_read_trylock);
int __lockfunc _spin_trylock(spinlock_t *lock)
{
@@ -57,7 +60,7 @@ int __lockfunc _write_trylock(rwlock_t *lock)
}
EXPORT_SYMBOL(_write_trylock);
-#ifndef CONFIG_PREEMPT
+#if !defined(CONFIG_PREEMPT) || !defined(CONFIG_SMP)
void __lockfunc _read_lock(rwlock_t *lock)
{
@@ -72,7 +75,7 @@ unsigned long __lockfunc _spin_lock_irqsave(spinlock_t *lock)
local_irq_save(flags);
preempt_disable();
- _raw_spin_lock_flags(lock, flags);
+ _raw_spin_lock_flags(lock, &flags);
return flags;
}
EXPORT_SYMBOL(_spin_lock_irqsave);

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