linux-kernel - Re: epoll behaviour after running out of descriptors

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Date:	Sun, 2 Nov 2008 23:17:07 +0100
From:	"Olaf van der Spek" <olafvdspek@...il.com>
To:	"Davide Libenzi" <davidel@...ilserver.org>
Cc:	"Linux Kernel Mailing List" <linux-kernel@...r.kernel.org>
Subject: Re: epoll behaviour after running out of descriptors

On Sun, Nov 2, 2008 at 10:17 PM, Davide Libenzi <davidel@...ilserver.org> wrote:
>> Wouldn't the port space require about 20+ k connects? This issue
>> happens after 1 k.
>
> The reason for "When accept returns EMFILE, I call epoll_wait and accept
> and it returns with another EMFILE." is because your sockets-close logic
> is broken.

It's not broken, it's designed that way. It's designed to hit the
descriptor limit and then close all sockets some time after.

> You get an event for the listening fd, you go call accept(2)
> and in one or two passes you fill up the avail fd space, then you go back
> calling epoll_wait(), and yet back to accept(2). This w/out triggering the
> file-close-relief code (yes, you fill up 1K fds *before* 30 seconds). Of
> course you get another EMFILE.

The second EMFILE doesn't make sense, epoll_wait shouldn't signal the
socket as ready again, right?
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