linux-kernel - Re: [PATCH] x86-32: Allocate irq stacks seperate from percpu area

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: <4CC965FF.8000601@kernel.org>
Date:	Thu, 28 Oct 2010 14:01:03 +0200
From:	Tejun Heo <tj@...nel.org>
To:	Eric Dumazet <eric.dumazet@...il.com>
CC:	Peter Zijlstra <peterz@...radead.org>,
	Brian Gerst <brgerst@...il.com>, x86@...nel.org,
	linux-kernel@...r.kernel.org, torvalds@...ux-foundation.org,
	mingo@...e.hu
Subject: Re: [PATCH] x86-32: Allocate irq stacks seperate from percpu area

Hello, Eric.

On 10/27/2010 10:55 PM, Eric Dumazet wrote:
> I changed the User/Kernel split from 3G/1G to 1G/3G so that I have
> LOWMEM on both nodes. Still pcpu allocates all percpu from node0.
...
> [    0.000000] setup_percpu: NR_CPUS:64 nr_cpumask_bits:64 nr_cpu_ids:16 nr_node_ids:8
> [    0.000000] PERCPU: Embedded 16 pages/cpu @bea00000 s41984 r0 d23552 u131072
> [    0.000000] pcpu-alloc: s41984 r0 d23552 u131072 alloc=1*2097152
> [    0.000000] pcpu-alloc: [0] 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 
> [    0.000000] setup_percpu: cpu=0 early_cpu_to_node()=0
> [    0.000000] setup_percpu: cpu=1 early_cpu_to_node()=0
> [    0.000000] setup_percpu: cpu=2 early_cpu_to_node()=0
> [    0.000000] setup_percpu: cpu=3 early_cpu_to_node()=0
> [    0.000000] setup_percpu: cpu=4 early_cpu_to_node()=0
> [    0.000000] setup_percpu: cpu=5 early_cpu_to_node()=0
> [    0.000000] setup_percpu: cpu=6 early_cpu_to_node()=0
> [    0.000000] setup_percpu: cpu=7 early_cpu_to_node()=0
> [    0.000000] setup_percpu: cpu=8 early_cpu_to_node()=0
> [    0.000000] setup_percpu: cpu=9 early_cpu_to_node()=0
> [    0.000000] setup_percpu: cpu=10 early_cpu_to_node()=0
> [    0.000000] setup_percpu: cpu=11 early_cpu_to_node()=0
> [    0.000000] setup_percpu: cpu=12 early_cpu_to_node()=0
> [    0.000000] setup_percpu: cpu=13 early_cpu_to_node()=0
> [    0.000000] setup_percpu: cpu=14 early_cpu_to_node()=0
> [    0.000000] setup_percpu: cpu=15 early_cpu_to_node()=0

So, this is the problem.  percpu uses early_cpu_to_node() to determine
which cpu belongs to which NUMA node and according to it all CPUs are
on node 0, so percpu is configured accordingly.  I have no idea why
early_cpu_to_node() is set up like that tho.  Ingo, Thomas, any ideas?

-- 
tejun
--
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/