From 32946b60f1bdfe74552e27651999ae498e6882d4 Mon Sep 17 00:00:00 2001 From: Keir Fraser Date: Sat, 24 Nov 2007 13:31:39 +0000 Subject: [Mini-OS] Fix domain blocking race A callback which wakes a thread may happen between the moment schedule() gives hand to the idle thread and the latter blocks the domain. Idle hence needs to atomically check that no thread is running and block, else awoken threads may have to wait up to 10 seconds. Signed-off-by: Samuel Thibault --- extras/mini-os/sched.c | 23 ++++++++++++++++++++--- 1 file changed, 20 insertions(+), 3 deletions(-) (limited to 'extras/mini-os/sched.c') diff --git a/extras/mini-os/sched.c b/extras/mini-os/sched.c index fbcffd463e..eedb1fe7ed 100644 --- a/extras/mini-os/sched.c +++ b/extras/mini-os/sched.c @@ -224,12 +224,29 @@ void wake(struct thread *thread) void idle_thread_fn(void *unused) { s_time_t until; + unsigned long flags; + struct list_head *iterator; + struct thread *next, *thread; for(;;) { schedule(); - /* block until the next timeout expires, or for 10 secs, whichever comes first */ - until = blocking_time(); - block_domain(until); + next = NULL; + local_irq_save(flags); + list_for_each(iterator, &idle_thread->thread_list) + { + thread = list_entry(iterator, struct thread, thread_list); + if(is_runnable(thread)) + { + next = thread; + break; + } + } + if (!next) { + /* block until the next timeout expires, or for 10 secs, whichever comes first */ + until = blocking_time(); + block_domain(until); + } + local_irq_restore(flags); wake_expired(); } } -- cgit v1.2.3