On 10/23, Enke Chen wrote: > > >> + /* > >> + * Send the pre-coredump signal to the parent if requested. > >> + */ > >> + read_lock(&tasklist_lock); > >> + notify = do_notify_parent_predump(current); > >> + read_unlock(&tasklist_lock); > >> + if (notify) > >> + cond_resched(); > > > > Hmm. I do not understand why do we need cond_resched(). And even if we need > > it, > > why we can't call it unconditionally? > > Remember the goal is to allow the parent (e.g., a process manager) to take > early > action. The "yield" before doing coredump will help.
I don't see how can it actually help... cond_resched() is nop if CONFIG_PREEMPT or should_resched() == 0. and the coredumping thread will certainly need to sleep/wait anyway. > > And once again, SIGCHLD/SIGUSR do not queue, this means that > > PR_SET_PREDUMP_SIG > > is pointless if you have 2 or more children. > > Hmm, could you point me to the code where SIGCHLD/SIGUSR is treated > differently > w.r.t. queuing? That does not sound right to me. see the legacy_queue() check. Any signal < SIGRTMIN do not queue. IOW, if SIGCHLD is already pending, then next SIGCHLD is simply ignored. Oleg.
