Messages in this thread | | | Date | Fri, 21 Mar 2014 19:49:14 +0100 | From | Oleg Nesterov <> | Subject | Re: [PATCH 0/2] wait: introduce WQ_FLAG_EXCLUSIVE_HEAD |
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On 03/21, Dilger, Andreas wrote: > > On 2014/03/20, 11:51 AM, "Oleg Nesterov" <oleg@redhat.com> wrote: > > >On 03/19, Oleg Nesterov wrote: > >> > >> OK, I'll try to test/cleanup/resend tomorrow. > > > >Cough. Still un-tested, sorry. I will test it somehow and report, > >but I'd like to send this for review right now. > > > >Because I simply can't decide what the new flag should actually > >do, so please ack/nack the semantics/naming at least. > > > >Changes: > > > > 1. I decided it would be better to change __wait_event() > > to accept wait.flags right now. This looks better in > > any case to me, and otherwise we need to introduce the > > __wait_exclusive_enum. > > > > The change looks trivial (both actually), please tell > > me if you think it doesn't deserve a separate patch. > > > > 2. I won't insist, but WQ_FLAG_EXCLUSIVE_HEAD can be used > > without WQ_FLAG_EXCLUSIVE. > > > > Unlikely this can be useful, but it looks more natural > > this way. Otherwise we need to add another check to > > ensure that WQ_FLAG_EXCLUSIVE_HEAD can't come alone. > > > > However, perhaps this means the new flag needs another > > name. I agree in advance with any. > > What about: > > #define WQ_FLAG_HEAD 0x02
I am fine either way ;)
But _HEAD looks a bit confusing too. This flag doesn't add at the head, it inserts the new entry before other exclusive tasks.
> #define WQ_FLAG_EXCLUSIVE_HEAD (WQ_FLAG_HEAD | WQ_FLAG_EXCLUSIVE) > > That avoids having WQ_FLAG_EXCLUSIVE_HEAD not actually meaning "exclusive"? > > Patches look reasonable at first glance. The second patch would need > to be changed to handle that WQ_FLAG_EXCLUSIVE_HEAD has both bits set > (probably just replace uses of WQ_FLAG_EXCLUSIVE_HEAD with WQ_FLAG_HEAD).
Yes, s/WQ_FLAG_EXCLUSIVE_HEAD/WQ_FLAG_HEAD/ is the only change we need in this case.
Other than define(WQ_FLAG_EXCLUSIVE_HEAD) of course, but this flags should only be used by ___wait_event() callers.
Peter, what do you think?
Oleg.
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