linux-kernel - Re: [dm-devel] [PATCH] DM-CRYPT: Scale to multiple CPUs

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

Message-ID: <Pine.LNX.4.64.1005312236570.6372@hs20-bc2-1.build.redhat.com>
Date:	Mon, 31 May 2010 22:39:37 -0400 (EDT)
From:	Mikulas Patocka <mpatocka@...hat.com>
To:	device-mapper development <dm-devel@...hat.com>
cc:	Milan Broz <mbroz@...hat.com>, ak@...ux.intel.com,
	linux-kernel@...r.kernel.org, herbert@...dor.hengli.com.au,
	Andi Kleen <andi@...stfloor.org>, agk@...hat.com
Subject: Re: [dm-devel] [PATCH] DM-CRYPT: Scale to multiple CPUs

> > >> 2) Per volume threads and mempools were added to solve low memory
> > >> problems (exhausted mempools), isn't now possible deadlock here again?
> > > 
> > > Increasing the number of parallel submitters does not increase deadlocks
> > > with mempool as long as they don't nest.  They would just
> > > block each other, but eventually make progress as one finishes. 
> > 
> > I mean if they nest of course, sorry for confusion.
> 
> No change to that, it's the same as it always worked.
> 
> Anyways, Right now you would need to nest more than 16 times I think
> to exhaust the mempool (or 8, but the pages are less critical I think)
> 
> For me that seems like a "don't do that if hurts" situation.

If the mempools are per-instance (they are), it can nest any number of 
times, because each nested instance will get new mempools. It is not a 
problem.

Mikulas
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/