linux-kernel - Re: aio: questions with ioctx_alloc() and large num_possible

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <x49twbw710j.fsf@segfault.boston.devel.redhat.com>
Date:   Fri, 28 Oct 2016 14:59:40 -0400
From:   Jeff Moyer <jmoyer@...hat.com>
To:     Benjamin LaHaise <bcrl@...ck.org>
Cc:     Mauricio Faria de Oliveira <mauricfo@...ux.vnet.ibm.com>,
        Kent Overstreet <kent.overstreet@...il.com>,
        Alexander Viro <viro@...iv.linux.org.uk>,
        linux-fsdevel@...r.kernel.org, linux-aio@...ck.org,
        linux-kernel@...r.kernel.org
Subject: Re: aio: questions with ioctx_alloc() and large num_possible_cpus()

Benjamin LaHaise <bcrl@...ck.org> writes:

> Today's high end systems are tomorrow's desktops...  It probably makes 

Well, to some degree I agree with you.  >100 processor high end systems
have been around for a long time, but we still don't have those on the
desktop.  ;-)

> sense to implement per-user limits rather than the current global limit, 
> and maybe even convert them to an rlimit to better fit in with the 
> available frameworks for managing these things.

I actually wrote a patch to do this back in 2007:
  http://www.gossamer-threads.com/lists/linux/kernel/1043934

It used the mlock rlimit.  I ultimately decided to rescind it, since
there were years of experience with the current tunable, and plenty of
documentation on it, too.  We could put aio-max-nr on the deprecated
path, though, if folks want to go that route.  Let me know and I can
investigate resurrecting that patch.  Though I would like input on
whether a new rlimit is desired.

Cheers,
Jeff