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linux-next/lib/spinlock_debug.c
Ingo Molnar fb1c8f93d8 [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>
2005-09-10 10:06:21 -07:00

258 lines
5.8 KiB
C

/*
* 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);
}