From: Alexander Monakov <amonakov@ispras.ru>
To: musl@lists.openwall.com
Subject: Re: Resuming work on new semaphore
Date: Fri, 24 Apr 2015 18:47:45 +0300 (MSK) [thread overview]
Message-ID: <alpine.LNX.2.11.1504241732410.2677@monopod.intra.ispras.ru> (raw)
In-Reply-To: <alpine.LNX.2.11.1504241235400.2677@monopod.intra.ispras.ru>
One more thought. In the original proposal, val[1] was a "wake count". By
now we have drifted away a bit from that concept, with val[1] being used not
only in post/timedwait, but also in trywait/getvalue, trywait explicitely
performing post-stealing, and getvalue accounting for that.
So how about we try to stick with the original vision, and say that val[1] is
strictly for waiters leaving futex wait via non-error path? The kernel tells
the poster via the return value of futex_wake whether the wake has caused any
waiter to resume execution. The kernel already knows if any waiter was there
to accept a wake, and lets us know. Can we somehow use that to implement
non-stealing wakeups?
Alexander
next prev parent reply other threads:[~2015-04-24 15:47 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-02 1:30 Rich Felker
2015-04-02 7:42 ` Alexander Monakov
2015-04-02 15:26 ` Rich Felker
2015-04-02 21:39 ` Alexander Monakov
2015-04-02 23:14 ` Rich Felker
2015-04-05 14:07 ` Alexander Monakov
2015-04-05 14:17 ` Alexander Monakov
2015-04-05 19:02 ` Rich Felker
2015-04-05 20:03 ` Alexander Monakov
2015-04-05 20:23 ` Rich Felker
2015-04-05 21:07 ` Alexander Monakov
2015-04-11 22:22 ` Alexander Monakov
2015-04-23 16:06 ` Rich Felker
2015-04-23 18:24 ` Alexander Monakov
2015-04-23 20:01 ` Alexander Monakov
2015-04-24 2:46 ` Rich Felker
2015-04-24 10:23 ` Alexander Monakov
2015-04-24 15:03 ` Rich Felker
2015-04-24 15:47 ` Alexander Monakov [this message]
2015-04-24 15:59 ` Rich Felker
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