From: Florian Weimer <fw@deneb.enyo.de>
To: "Ted Ts'o" <tytso@mit.edu>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>,
martin capitanio <m@capitanio.org>,
linux-kernel@vger.kernel.org, torvalds@linux-foundation.org
Subject: Re: mmap, the language go, problems with the linux kernel
Date: Wed, 16 Feb 2011 21:51:32 +0100 [thread overview]
Message-ID: <87mxlvsnxn.fsf@mid.deneb.enyo.de> (raw)
In-Reply-To: <20110213012227.GC2598@thunk.org> (Ted Ts'o's message of "Sat, 12 Feb 2011 20:22:27 -0500")
* Ted Ts'o:
>> The odd thing is that prot==0 does *not* count against the
>> vm.overcommit_memory=2 limit, only against ulimit -v. The limit is
>> only enforced for the parts on which mprotect is called. I think this
>> should really be part of the public API (I'm not sure if it is right
>> now, it could well be an accident), to avoid the problems you
>> describe.
>
> The overcommit_memory logic does not include any pages which are
> mapped read-only.
A colleague tells me that according to his tests, this depends on the
history of the page, as expected.
> Technically that's not quite enough --- in theory you could have a
> debugging attach to every single read-only text page and set
> breakpoints on every single page.
Those cases do not matter because setting a breakpoint can fail with
ENOMEM. You only have to take into account possibly future operations
which cannot fail with ENOMEM.
next prev parent reply other threads:[~2011-02-16 20:51 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-02-08 12:37 mmap, the language go, problems with the linux kernel martin capitanio
2011-02-08 13:26 ` Alan Cox
2011-02-12 14:28 ` Florian Weimer
2011-02-13 1:22 ` Ted Ts'o
2011-02-16 20:51 ` Florian Weimer [this message]
2011-02-08 16:23 ` Linus Torvalds
2011-02-09 16:30 ` Martin Capitanio
2011-02-09 16:40 ` Russ Cox
2011-02-09 19:17 ` Ted Ts'o
2011-02-09 19:56 ` [golang-dev] " Ian Lance Taylor
2011-02-09 20:11 ` Ted Ts'o
2011-02-16 18:16 ` Hannes Frederic Sowa
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