From: Jeff Garzik <jeff@garzik.org>
To: Pete Zaitcev <zaitcev@redhat.com>
Cc: Project Hail List <hail-devel@vger.kernel.org>
Subject: Re: [tabled patch 1/1] Fix spinning if EOF from client
Date: Fri, 14 May 2010 22:02:51 -0400 [thread overview]
Message-ID: <4BEE00CB.6070900@garzik.org> (raw)
In-Reply-To: <20100511220954.3bb154a0@redhat.com>
On 05/12/2010 12:09 AM, Pete Zaitcev wrote:
> I observed that Tabled sometimes starts spinning on CPU. It happens when
> it manages to receive a EOF from client (reads zero bytes from the socket).
>
> The fix is to treat EOF as an error and simply dispose of the cli.
>
> However, we need to know when there are no bytes to be read from
> a socket that is still open. To that end we modify the API of cli_read:
> now it only returns zero in case of EOF, and passes -EAGAIN up.
>
> In order to prevent busy spinning for slow clients, callers of cli_read
> return false to the dispatch loop in case of -EAGAIN.
>
> Note that this patch assumes that zero bytes is always EOF, and that
> we receive -EAGAIN if there is nothing to read in the first place.
>
> Signed-off-by: Pete Zaitcev<zaitcev@redhat.com>
applied
prev parent reply other threads:[~2010-05-15 2:02 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-12 4:09 [tabled patch 1/1] Fix spinning if EOF from client Pete Zaitcev
2010-05-15 2:02 ` Jeff Garzik [this message]
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