diff options
Diffstat (limited to 'include/asm-ia64/system.h')
| -rw-r--r-- | include/asm-ia64/system.h | 25 |
1 files changed, 0 insertions, 25 deletions
diff --git a/include/asm-ia64/system.h b/include/asm-ia64/system.h index 99b6f307e94b..cd4233d66f15 100644 --- a/include/asm-ia64/system.h +++ b/include/asm-ia64/system.h @@ -256,32 +256,7 @@ extern void ia64_load_extra (struct task_struct *task); # define switch_to(prev,next,last) __switch_to(prev, next, last) #endif -/* - * On IA-64, we don't want to hold the runqueue's lock during the low-level context-switch, - * because that could cause a deadlock. Here is an example by Erich Focht: - * - * Example: - * CPU#0: - * schedule() - * -> spin_lock_irq(&rq->lock) - * -> context_switch() - * -> wrap_mmu_context() - * -> read_lock(&tasklist_lock) - * - * CPU#1: - * sys_wait4() or release_task() or forget_original_parent() - * -> write_lock(&tasklist_lock) - * -> do_notify_parent() - * -> wake_up_parent() - * -> try_to_wake_up() - * -> spin_lock_irq(&parent_rq->lock) - * - * If the parent's rq happens to be on CPU#0, we'll wait for the rq->lock - * of that CPU which will not be released, because there we wait for the - * tasklist_lock to become available. - */ #define __ARCH_WANT_UNLOCKED_CTXSW - #define ARCH_HAS_PREFETCH_SWITCH_STACK #define ia64_platform_is(x) (strcmp(x, platform_name) == 0) |