linux-kernel - Re: [PATCH 2/2] autonuma: fix typo in blind balance

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: <20120319173522.GG24602@redhat.com>
Date:	Mon, 19 Mar 2012 18:35:22 +0100
From:	Andrea Arcangeli <aarcange@...hat.com>
To:	Hillf Danton <dhillf@...il.com>
Cc:	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/2] autonuma: fix typo in blind balance

On Mon, Mar 19, 2012 at 08:59:59PM +0800, Hillf Danton wrote:
> Since it is certain that nid is not online in each round of for-loop,
> it is replaced with given node id.
> 
> Signed-off-by: Hillf Danton <dhillf@...il.com>
> ---
> 
> --- a/kernel/sched/numa.c	Sat Mar 17 11:01:40 2012
> +++ b/kernel/sched/numa.c	Mon Mar 19 20:04:00 2012
> @@ -34,7 +34,7 @@ static int autonuma_balance_blind(struct
>  		selected_nid = cpu_nid;
> 
>  		nr_mm_max = 0;
> -		for_each_cpu_and(cpu, cpumask_of_node(nid), allowed) {
> +		for_each_cpu_and(cpu, cpumask_of_node(cpu_nid), allowed) {
>  			struct rq *rq = cpu_rq(cpu);
>  			if (rq->curr->mm == mm)
>  				nr_mm_max++;

Correct! gcc should have spwaned an unintialized warning too? I may
have broke it by accident with the editor after I disabled the
function. AUTONUMA_BALANCE_BLIND is not set so this function isn't
getting built right now.

I tried to keep enabled only the minimum, kind of stuff that if you
remove it, something will degrade significantly. 

With the algorithms I developed before the current
sched_autonuma_balance, having autonuma_balance_blind made huge
difference, not anymore once I had something way better as a core
balancer, so then I considered autonuma_balance_blind more like an
hack and I disabled it.

I'm impressed how fast you found these two bugs, appreciated!

If you've high level opinions on the design, comments welcome.

Thanks,
Andrea
--
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/