Messages in this thread | | | From | Peng Tao <> | Date | Wed, 19 Mar 2014 10:22:59 +0800 | Subject | Re: [PATCH RFC] sched: introduce add_wait_queue_exclusive_head |
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On Wed, Mar 19, 2014 at 12:23 AM, Oleg Nesterov <oleg@redhat.com> wrote: > On 03/18, Peng Tao wrote: >> >> On Tue, Mar 18, 2014 at 10:05 PM, Peter Zijlstra <peterz@infradead.org> wrote: >> > >> > Unless you cannot use ___wait() and really need to open-code the >> > wait_event() stuff. >> > >> Lustre's private l_wait_event() stuff takes care to (un)mask >> LUSTRE_FATAL_SIGS > > Hmm. This is off-topic but after the quick grep LUSTRE_FATAL_SIGS/etc > looks suspicious. > > Firtsly, cfs_block_sigs/cfs_block_sigsinv/etc are not exactly right, > they need set_current_blocked(). And you can read "old" lockless. > It seems that set_current_blocked() is not exported. Can we ask to export it?
And looking at other similar places like coda_block_signals(), it doesn't call set_current_blocked() either. So it needs set_current_blocked() as well.
> And note that cfs_block_sigsinv(0) (which should block all signals) > can't actually protect from SIGKILL (or in fact from another fatal > signal) or SIGSTOP if the caller is multithreaded. Or ptrace, or > freezer. > >> and always wait in TASK_INTERRUPTIBLE state. > > and it seems that __wstate passed to waitq_wait/waitq_timedwait is > simply ignored. > Yes. That needs to be dropped.
>> It looks to me that we can at least wrap l_wait_event() on top of >> wait_event_interruptible/wait_event_timeout_interruptible. > > l_wait_event looks really complicated ;) but perhaps you can rewrite > it on top of ___wait_event(), note that condition/cmd can do anything > you want. > Yeah, I meant to say __wait_event(). Thanks for correcting me.
Thanks, Tao
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