more sync wakeups, 2.6.5-rc3-mm1
PATCH 1/1 more sync wakeups, 2.6.5-rc3-mm1
the attached patch extends sync wakeups to the process sys_exit() path
too: the chldwait wakeup can be done sync, since we know that the process is going to exit (and thus deschedule).
the most visible effect of this change is strace's behavior on SMP
systems: it now stays on a single CPU, together with the traced child. (previously it would run in parallel to the child, bouncing around madly.)
compiled & tested.
Ingo
(patch attached now.)
Quoted 4 lines · Ingo Molnar
the attached patch extends sync wakeups to the process
sys_exit()path
too: the chldwait wakeup can be done sync, since we know that the process is going to exit (and thus deschedule).
Quoted 8 lines
the most visible effect of this change is strace's behavior on SMP
systems: it now stays on a single CPU, together with the traced child. (previously it would run in parallel to the child, bouncing around madly.)compiled & tested.
Ingo
kernel/signal.c renamed from kernel/signal.c.orig +2 -2
@@ -1386,12 +1386,12 @@ static inline void __wake_up_parent(stru* Fortunately this is not necessary for thread groups: */ if (p->tgid == tsk->tgid) { -wake_up_interruptible (&tsk->wait_chldexit); +wake_up_interruptible_sync (&tsk->wait_chldexit);return ; } do { - wake_up_interruptible(&tsk->wait_chldexit); + wake_up_interruptible_sync(&tsk->wait_chldexit); tsk = next_thread(tsk); if (tsk->signal != parent->signal) BUG();