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To: Kostik Belousov <kostikbel@gmail.com>
From: "Poul-Henning Kamp" <phk@phk.freebsd.dk>
In-Reply-To: Your message of "Fri, 04 Jan 2008 15:48:29 +0200."
	<20080104134829.GA57756@deviant.kiev.zoral.com.ua> 
Date: Mon, 07 Jan 2008 09:08:35 +0000
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Sender: phk@critter.freebsd.dk
Cc: Dag-Erling Sm??rgrav <des@des.no>, freebsd-current@freebsd.org,
	Robert Watson <rwatson@freebsd.org>, Jason Evans <jasone@freebsd.org>,
	Igor Mozolevsky <igor@hybrid-lab.co.uk>
Subject: Re: sbrk(2) broken 
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In message <20080104134829.GA57756@deviant.kiev.zoral.com.ua>, Kostik Belousov 
writes:

>On Fri, Jan 04, 2008 at 02:12:50PM +0100, Dag-Erling Sm??rgrav wrote:
>> "Igor Mozolevsky" <igor@hybrid-lab.co.uk> writes:
>> > This makes memory management in the userland hideously and
>> > unnecessarily complicated. It's simpler to have SIGDANGER [...]
>> 
>> You don't seem to understand what Poul-Henning was trying to point out,
>> which is that broadcasting SIGDANGER can make a bad situation much, much
>> worse by waking up and paging in every single process in the system,
>
>By making the default action for SIGDANGER to be SIG_IGN, this problem
>would be mostly solved. Only processes that actually care about SIGDANGER
>and installing the handler for it would require some non-trivial and
>resource-hungry operation.

This is a non-starter, if SIGDANGER is to have any effect, all
processes that use malloc(3) should react to it.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.