linux-kernel - Re: [PATCH 1/3] epoll: increase default max_user

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Message-ID: <19f34abd0901280308w18407fd5rd4d7d95e3799cf60@mail.gmail.com>
Date:	Wed, 28 Jan 2009 12:08:20 +0100
From:	Vegard Nossum <vegard.nossum@...il.com>
To:	Bron Gondwana <brong@...tmail.fm>
Cc:	Davide Libenzi <davidel@...ilserver.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Greg KH <gregkh@...e.de>
Subject: Re: [PATCH 1/3] epoll: increase default max_user_instances to 1024

On Wed, Jan 28, 2009 at 6:32 AM, Bron Gondwana <brong@...tmail.fm> wrote:
> That's clearly not happening here - so it seems that maybe our "happy
> medium" is actually in closer inspection of what's going on rather than
> a blanket low N to keep N^2 down.

Mh, could another solution to this all be to limit the number times
you can add a single epoll descriptor to another descriptor's set?

So you would still get the "upwards cascading" behaviour (i.e. A can
monitor B and C), but the "downwards cascading" would be prohibited
(i.e. B and C can't both monitor A).

I think this is a reasonable alternative, which would again allow a
number of epoll instances limited only by the number of open file
descriptors.


Vegard

-- 
"The animistic metaphor of the bug that maliciously sneaked in while
the programmer was not looking is intellectually dishonest as it
disguises that the error is the programmer's own creation."
	-- E. W. Dijkstra, EWD1036
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