From: Ingo Molnar <mingo@kernel.org>
To: Jason Baron <jbaron@akamai.com>
Cc: peterz@infradead.org, mingo@redhat.com, viro@zeniv.linux.org.uk,
akpm@linux-foundation.org, normalperson@yhbt.net,
davidel@xmailserver.org, mtk.manpages@gmail.com,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-api@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>,
Linus Torvalds <torvalds@linux-foundation.org>,
Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: Re: [PATCH v2 2/2] epoll: introduce EPOLLEXCLUSIVE and EPOLLROUNDROBIN
Date: Wed, 18 Feb 2015 18:45:33 +0100 [thread overview]
Message-ID: <20150218174533.GB31566@gmail.com> (raw)
In-Reply-To: <54E4CE14.5010708@akamai.com>
* Jason Baron <jbaron@akamai.com> wrote:
> So in the case of multiple threads per epoll set, we
> currently add to the head of wakeup queue exclusively in
> 'epoll_wait()', and then subsequently remove from the
> queue once 'epoll_wait()' returns. So I don't think this
> patch addresses balancing on a per epoll set basis.
Okay, so I was confused about how the code works.
> I think we could address the case you describe by simply
> doing __add_wait_queue_tail_exclusive() instead of
> __add_wait_queue_exclusive() in epoll_wait(). [...]
Yes.
> [...] However, I think the userspace API change is less
> clear since epoll_wait() doesn't currently have an
> 'input' events argument as epoll_ctl() does.
... but the change would be a bit clearer and somewhat more
flexible: LIFO or FIFO queueing, right?
But having the queueing model as part of the epoll context
is a legitimate approach as well.
Thanks,
Ingo
next prev parent reply other threads:[~2015-02-18 17:45 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-17 19:33 [PATCH v2 0/2] Add epoll round robin wakeup mode Jason Baron
2015-02-17 19:33 ` [PATCH v2 1/2] sched/wait: add " Jason Baron
2015-02-17 19:33 ` [PATCH v2 2/2] epoll: introduce EPOLLEXCLUSIVE and EPOLLROUNDROBIN Jason Baron
2015-02-18 8:07 ` Ingo Molnar
2015-02-18 15:42 ` Jason Baron
2015-02-18 16:33 ` Ingo Molnar
2015-02-18 17:38 ` Jason Baron
2015-02-18 17:45 ` Ingo Molnar [this message]
2015-02-18 17:51 ` Ingo Molnar
2015-02-18 22:18 ` Eric Wong
2015-02-19 3:26 ` Jason Baron
2015-02-22 0:24 ` Eric Wong
2015-02-25 15:48 ` Jason Baron
2015-02-18 23:12 ` Andy Lutomirski
[not found] ` <CAPh34mcPNQELwZCDTHej+HK=bpWgJ=jb1LeCtKoUHVgoDJOJoQ@mail.gmail.com>
2015-02-27 22:24 ` Jason Baron
2015-02-17 19:46 ` [PATCH v2 0/2] Add epoll round robin wakeup mode Andy Lutomirski
2015-02-17 20:33 ` Jason Baron
2015-02-17 21:09 ` Andy Lutomirski
2015-02-18 3:15 ` Jason Baron
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