linux-kernel - Re: [PATCH 2/3] sched: introduce per-cpu var next

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:   Tue, 24 Apr 2018 14:47:12 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     subhra mazumdar <subhra.mazumdar@...cle.com>
Cc:     linux-kernel@...r.kernel.org, mingo@...hat.com,
        daniel.lezcano@...aro.org, steven.sistare@...cle.com,
        dhaval.giani@...cle.com, rohit.k.jain@...cle.com
Subject: Re: [PATCH 2/3] sched: introduce per-cpu var next_cpu to track
 search limit

On Mon, Apr 23, 2018 at 05:41:15PM -0700, subhra mazumdar wrote:
> @@ -17,6 +17,7 @@
>  #include <trace/events/sched.h>
>  
>  DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
> +DEFINE_PER_CPU_SHARED_ALIGNED(int, next_cpu);
>  
>  #if defined(CONFIG_SCHED_DEBUG) && defined(HAVE_JUMP_LABEL)
>  /*
> @@ -6018,6 +6019,7 @@ void __init sched_init(void)
>  		struct rq *rq;
>  
>  		rq = cpu_rq(i);
> +		per_cpu(next_cpu, i) = -1;

If you leave it uninitialized it'll be 0, and we can avoid that extra
branch in the next patch, no?