linux-kernel - Re: [PATCH] x86: UV BAU Increase maximum CPUs per socket/hub

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]

Date:	Sat, 1 Nov 2014 21:23:47 +0100 (CET)
From:	Thomas Gleixner <tglx@...utronix.de>
To:	James Custer <jcuster@....com>
cc:	x86@...nel.org, linux-kernel@...r.kernel.org,
	Ingo Molnar <mingo@...hat.com>,
	"H . Peter Anvin" <hpa@...or.com>, Russ Anderson <rja@....com>
Subject: Re: [PATCH] x86: UV BAU Increase maximum CPUs per socket/hub

On Fri, 31 Oct 2014, James Custer wrote:

> We have encountered hardware with 18 cores/socket that gives 36 CPUs/socket
> with hyperthreading enabled. This exceeds the current MAX_CPUS_PER_SOCKET
> causing a failure in get_cpu_topology. Increase MAX_CPUS_PER_SOCKET to 64
> and MAX_CPUS_PER_UVHUB to 128.
> 
> Additionally, this exposed another bug. When get_cpu_topology fails, we
> need to make sure that we do not use bau_control->statp (e.g. when a
> user reads /proc/sgi_uv/ptc_statistics causing ptc_seq_show to be
> invoked). In uv_bau_init we call set_bau_off() when
> init_per_cpu()->get_cpu_topology() fails -- therefore, to avoid
> referencing a NULL pointer we add code that detects when the bau is off
> and print out the bau is disabled.

Can you please split this in two patches. One fixing the ptc_seq_show
bug and the other increasing the constants. 
 
If someone looks for a fix for the ptc_seq_show wreckage he definitly
is not going to look at a patch which increases the number of cpus per
socket.

Thanks,

	tglx
--
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/