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author | Ingo Molnar <mingo@elte.hu> | 2005-09-10 09:25:56 +0200 |
---|---|---|
committer | Linus Torvalds <torvalds@g5.osdl.org> | 2005-09-10 19:06:21 +0200 |
commit | fb1c8f93d869b34cacb8b8932e2b83d96a19d720 (patch) | |
tree | a006d078aa02e421a7dc4793c335308204859d36 /lib/spinlock_debug.c | |
parent | [PATCH] Subject: PATCH: fix numa caused compile warnings (diff) | |
download | linux-fb1c8f93d869b34cacb8b8932e2b83d96a19d720.tar.xz linux-fb1c8f93d869b34cacb8b8932e2b83d96a19d720.zip |
[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 '')
-rw-r--r-- | lib/spinlock_debug.c | 257 |
1 files changed, 257 insertions, 0 deletions
diff --git a/lib/spinlock_debug.c b/lib/spinlock_debug.c new file mode 100644 index 000000000000..906ad101eab3 --- /dev/null +++ b/lib/spinlock_debug.c @@ -0,0 +1,257 @@ +/* + * Copyright 2005, Red Hat, Inc., Ingo Molnar + * Released under the General Public License (GPL). + * + * This file contains the spinlock/rwlock implementations for + * DEBUG_SPINLOCK. + */ + +#include <linux/config.h> +#include <linux/spinlock.h> +#include <linux/interrupt.h> +#include <linux/delay.h> + +static void spin_bug(spinlock_t *lock, const char *msg) +{ + static long print_once = 1; + struct task_struct *owner = NULL; + + if (xchg(&print_once, 0)) { + if (lock->owner && lock->owner != SPINLOCK_OWNER_INIT) + owner = lock->owner; + printk("BUG: spinlock %s on CPU#%d, %s/%d\n", + msg, smp_processor_id(), current->comm, current->pid); + printk(" lock: %p, .magic: %08x, .owner: %s/%d, .owner_cpu: %d\n", + lock, lock->magic, + owner ? owner->comm : "<none>", + owner ? owner->pid : -1, + lock->owner_cpu); + dump_stack(); +#ifdef CONFIG_SMP + /* + * We cannot continue on SMP: + */ +// panic("bad locking"); +#endif + } +} + +#define SPIN_BUG_ON(cond, lock, msg) if (unlikely(cond)) spin_bug(lock, msg) + +static inline void debug_spin_lock_before(spinlock_t *lock) +{ + SPIN_BUG_ON(lock->magic != SPINLOCK_MAGIC, lock, "bad magic"); + SPIN_BUG_ON(lock->owner == current, lock, "recursion"); + SPIN_BUG_ON(lock->owner_cpu == raw_smp_processor_id(), + lock, "cpu recursion"); +} + +static inline void debug_spin_lock_after(spinlock_t *lock) +{ + lock->owner_cpu = raw_smp_processor_id(); + lock->owner = current; +} + +static inline void debug_spin_unlock(spinlock_t *lock) +{ + SPIN_BUG_ON(lock->magic != SPINLOCK_MAGIC, lock, "bad magic"); + SPIN_BUG_ON(!spin_is_locked(lock), lock, "already unlocked"); + SPIN_BUG_ON(lock->owner != current, lock, "wrong owner"); + SPIN_BUG_ON(lock->owner_cpu != raw_smp_processor_id(), + lock, "wrong CPU"); + lock->owner = SPINLOCK_OWNER_INIT; + lock->owner_cpu = -1; +} + +static void __spin_lock_debug(spinlock_t *lock) +{ + int print_once = 1; + u64 i; + + for (;;) { + for (i = 0; i < loops_per_jiffy * HZ; i++) { + cpu_relax(); + if (__raw_spin_trylock(&lock->raw_lock)) + return; + } + /* lockup suspected: */ + if (print_once) { + print_once = 0; + printk("BUG: spinlock lockup on CPU#%d, %s/%d, %p\n", + smp_processor_id(), current->comm, current->pid, + lock); + dump_stack(); + } + } +} + +void _raw_spin_lock(spinlock_t *lock) +{ + debug_spin_lock_before(lock); + if (unlikely(!__raw_spin_trylock(&lock->raw_lock))) + __spin_lock_debug(lock); + debug_spin_lock_after(lock); +} + +int _raw_spin_trylock(spinlock_t *lock) +{ + int ret = __raw_spin_trylock(&lock->raw_lock); + + if (ret) + debug_spin_lock_after(lock); +#ifndef CONFIG_SMP + /* + * Must not happen on UP: + */ + SPIN_BUG_ON(!ret, lock, "trylock failure on UP"); +#endif + return ret; +} + +void _raw_spin_unlock(spinlock_t *lock) +{ + debug_spin_unlock(lock); + __raw_spin_unlock(&lock->raw_lock); +} + +static void rwlock_bug(rwlock_t *lock, const char *msg) +{ + static long print_once = 1; + + if (xchg(&print_once, 0)) { + printk("BUG: rwlock %s on CPU#%d, %s/%d, %p\n", msg, + smp_processor_id(), current->comm, current->pid, lock); + dump_stack(); +#ifdef CONFIG_SMP + /* + * We cannot continue on SMP: + */ + panic("bad locking"); +#endif + } +} + +#define RWLOCK_BUG_ON(cond, lock, msg) if (unlikely(cond)) rwlock_bug(lock, msg) + +static void __read_lock_debug(rwlock_t *lock) +{ + int print_once = 1; + u64 i; + + for (;;) { + for (i = 0; i < loops_per_jiffy * HZ; i++) { + cpu_relax(); + if (__raw_read_trylock(&lock->raw_lock)) + return; + } + /* lockup suspected: */ + if (print_once) { + print_once = 0; + printk("BUG: read-lock lockup on CPU#%d, %s/%d, %p\n", + smp_processor_id(), current->comm, current->pid, + lock); + dump_stack(); + } + } +} + +void _raw_read_lock(rwlock_t *lock) +{ + RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic"); + if (unlikely(!__raw_read_trylock(&lock->raw_lock))) + __read_lock_debug(lock); +} + +int _raw_read_trylock(rwlock_t *lock) +{ + int ret = __raw_read_trylock(&lock->raw_lock); + +#ifndef CONFIG_SMP + /* + * Must not happen on UP: + */ + RWLOCK_BUG_ON(!ret, lock, "trylock failure on UP"); +#endif + return ret; +} + +void _raw_read_unlock(rwlock_t *lock) +{ + RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic"); + __raw_read_unlock(&lock->raw_lock); +} + +static inline void debug_write_lock_before(rwlock_t *lock) +{ + RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic"); + RWLOCK_BUG_ON(lock->owner == current, lock, "recursion"); + RWLOCK_BUG_ON(lock->owner_cpu == raw_smp_processor_id(), + lock, "cpu recursion"); +} + +static inline void debug_write_lock_after(rwlock_t *lock) +{ + lock->owner_cpu = raw_smp_processor_id(); + lock->owner = current; +} + +static inline void debug_write_unlock(rwlock_t *lock) +{ + RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic"); + RWLOCK_BUG_ON(lock->owner != current, lock, "wrong owner"); + RWLOCK_BUG_ON(lock->owner_cpu != raw_smp_processor_id(), + lock, "wrong CPU"); + lock->owner = SPINLOCK_OWNER_INIT; + lock->owner_cpu = -1; +} + +static void __write_lock_debug(rwlock_t *lock) +{ + int print_once = 1; + u64 i; + + for (;;) { + for (i = 0; i < loops_per_jiffy * HZ; i++) { + cpu_relax(); + if (__raw_write_trylock(&lock->raw_lock)) + return; + } + /* lockup suspected: */ + if (print_once) { + print_once = 0; + printk("BUG: write-lock lockup on CPU#%d, %s/%d, %p\n", + smp_processor_id(), current->comm, current->pid, + lock); + dump_stack(); + } + } +} + +void _raw_write_lock(rwlock_t *lock) +{ + debug_write_lock_before(lock); + if (unlikely(!__raw_write_trylock(&lock->raw_lock))) + __write_lock_debug(lock); + debug_write_lock_after(lock); +} + +int _raw_write_trylock(rwlock_t *lock) +{ + int ret = __raw_write_trylock(&lock->raw_lock); + + if (ret) + debug_write_lock_after(lock); +#ifndef CONFIG_SMP + /* + * Must not happen on UP: + */ + RWLOCK_BUG_ON(!ret, lock, "trylock failure on UP"); +#endif + return ret; +} + +void _raw_write_unlock(rwlock_t *lock) +{ + debug_write_unlock(lock); + __raw_write_unlock(&lock->raw_lock); +} |