From e0a602963485a2f109ae1521c0c55507304c63ed Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Tue, 7 Feb 2006 12:58:54 -0800 Subject: [PATCH] [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 Cc: Andi Kleen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/spinlock_debug.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/lib/spinlock_debug.c b/lib/spinlock_debug.c index c8bb8cc899..d8b6bb419d 100644 --- a/lib/spinlock_debug.c +++ b/lib/spinlock_debug.c @@ -72,9 +72,9 @@ static void __spin_lock_debug(spinlock_t *lock) for (;;) { for (i = 0; i < loops_per_jiffy * HZ; i++) { - cpu_relax(); if (__raw_spin_trylock(&lock->raw_lock)) return; + __delay(1); } /* lockup suspected: */ if (print_once) { @@ -144,9 +144,9 @@ static void __read_lock_debug(rwlock_t *lock) for (;;) { for (i = 0; i < loops_per_jiffy * HZ; i++) { - cpu_relax(); if (__raw_read_trylock(&lock->raw_lock)) return; + __delay(1); } /* lockup suspected: */ if (print_once) { @@ -217,9 +217,9 @@ static void __write_lock_debug(rwlock_t *lock) for (;;) { for (i = 0; i < loops_per_jiffy * HZ; i++) { - cpu_relax(); if (__raw_write_trylock(&lock->raw_lock)) return; + __delay(1); } /* lockup suspected: */ if (print_once) { -- 2.39.5