linux-kernel - Re: What was the problem with quicklists and x86-64?

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]

Date:	Thu, 13 Dec 2007 12:53:11 -0800 (PST)
From:	Christoph Lameter <clameter@....com>
To:	Benjamin Herrenschmidt <benh@...nel.crashing.org>
cc:	Jeremy Fitzhardinge <jeremy@...p.org>,
	Suresh Siddha <suresh.b.siddha@...el.com>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Ingo Molnar <mingo@...e.hu>, Andi Kleen <ak@...e.de>,
	Tony Luck <tony.luck@...el.com>,
	Asit Mallick <asit.k.mallick@...el.com>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: What was the problem with quicklists and x86-64?

On Fri, 14 Dec 2007, Benjamin Herrenschmidt wrote:

> > These issues only exist with NUMA because of the freeing of off node pages 
> > before the TLB flush was done. There was a discussion about this issue and 
> > my fix of simply not freeing the offnode pages early was ignored. Instead 
> > the x86_64 implementation (which has no problems that I know of) was 
> > pulled leaving the issue open in the core. Benjamin Herrrenschmidt 
> > wanted to take a look at these issues (CCing him).
> 
> I don't know how NUMA gets in the picture there, it's probably very x86
> specific thing. The issue we have here happens on other platforms
> unrelated to NUMA. The fact that is tired to NUMA on x86 might be due to
> the way the HW tablewalk operates on these. 

This is a generic NUMA issue here! Quicklist pages that are not on 
the current node are freed without waiting for the TLB flush. The patch 
that I posted fixes that by requiring that all pages be flushed. 
--
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/