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[PATCH] Fix spinlock debugging delays to not time out too early 

The spinlock-debug wait-loop was using loops_per_jiffy to detect too long
spinlock waits - but on fast CPUs this led to a way too fast timeout and false
messages.

The fix is to include a __delay(1) call in the loop, to correctly approximate
the intended delay timeout of 1 second.  The code assumes that every
architecture implements __delay(1) to last around 1/(loops_per_jiffy*HZ)
seconds.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Ingo Molnar 2006-02-07 12:58:54 -08:00 committed by Linus Torvalds
parent 8519fb30e4
commit e0a6029634
1 changed files with 3 additions and 3 deletions
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6
lib/spinlock_debug.c
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@ -72,9 +72,9 @@ static void __spin_lock_debug(spinlock_t *lock)
for (;;) { for (;;) {
for (i = 0; i < loops_per_jiffy * HZ; i++) { for (i = 0; i < loops_per_jiffy * HZ; i++) {
cpu_relax();
if (__raw_spin_trylock(&lock->raw_lock)) if (__raw_spin_trylock(&lock->raw_lock))
return; return;
__delay(1);
} }
/* lockup suspected: */ /* lockup suspected: */
if (print_once) { if (print_once) {
@ -144,9 +144,9 @@ static void __read_lock_debug(rwlock_t *lock)
for (;;) { for (;;) {
for (i = 0; i < loops_per_jiffy * HZ; i++) { for (i = 0; i < loops_per_jiffy * HZ; i++) {
cpu_relax();
if (__raw_read_trylock(&lock->raw_lock)) if (__raw_read_trylock(&lock->raw_lock))
return; return;
__delay(1);
} }
/* lockup suspected: */ /* lockup suspected: */
if (print_once) { if (print_once) {
@ -217,9 +217,9 @@ static void __write_lock_debug(rwlock_t *lock)
for (;;) { for (;;) {
for (i = 0; i < loops_per_jiffy * HZ; i++) { for (i = 0; i < loops_per_jiffy * HZ; i++) {
cpu_relax();
if (__raw_write_trylock(&lock->raw_lock)) if (__raw_write_trylock(&lock->raw_lock))
return; return;
__delay(1);
} }
/* lockup suspected: */ /* lockup suspected: */
if (print_once) { if (print_once) {