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From: Jiri Olsa <jolsa@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Andi Kleen <andi@firstfloor.org>,
	linux-kernel@vger.kernel.org, Andi Kleen <ak@linux.intel.com>,
	x86@kernel.org, Ingo Molnar <mingo@kernel.org>,
	Frank Ramsay <framsay@redhat.com>
Subject: Re: [RFC][PATCH] x86/smp: Fix __max_logical_packages value setup
Date: Wed, 10 Aug 2016 16:00:33 +0200	[thread overview]
Message-ID: <20160810140033.GA23798@krava> (raw)
In-Reply-To: <20160810135417.GP30192@twins.programming.kicks-ass.net>

On Wed, Aug 10, 2016 at 03:54:17PM +0200, Peter Zijlstra wrote:
> On Wed, Aug 03, 2016 at 06:23:58PM +0200, Jiri Olsa wrote:

SNIP

> > ---
> > diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
> > index 157bf0957219..484f7d357c77 100644
> > --- a/arch/x86/kernel/smpboot.c
> > +++ b/arch/x86/kernel/smpboot.c
> > @@ -340,7 +340,7 @@ static void __init smp_init_package_map(void)
> >  		ncpus = 1;
> >  	}
> >  
> > -	__max_logical_packages = DIV_ROUND_UP(total_cpus, ncpus);
> > +	__max_logical_packages = total_cpus;
> 
> This seems undesirable.. it would grow the bitmap unnecessarily big on
> most setups.
> 
> Is there no way to detect the brain damage inflicted by that BIOS option
> and fudge ncpus in that case?

yea, I have no idea.. that's why this is RFC ;-)

maybe we could also gradually allocate this bitmap
in topology_update_package_map.. I'll check on that

jirka

  reply	other threads:[~2016-08-10 18:46 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-08-03 16:23 [RFC][PATCH] x86/smp: Fix __max_logical_packages value setup Jiri Olsa
2016-08-10 11:41 ` Jiri Olsa
2016-08-10 13:54 ` Peter Zijlstra
2016-08-10 14:00   ` Jiri Olsa [this message]
2016-08-10 14:15     ` Jiri Olsa
2016-08-10 15:52       ` Peter Zijlstra
2016-08-10 16:14         ` [PATCH] " Jiri Olsa
2016-08-11 12:48           ` Peter Zijlstra
2016-08-11 13:05             ` Jiri Olsa
2016-08-11 13:46               ` Peter Zijlstra
2016-08-12 12:24                 ` Jiri Olsa
2016-08-12 13:12                   ` Jiri Olsa
2016-08-15  9:04                   ` Peter Zijlstra
2016-08-15 10:17                     ` Jiri Olsa
2016-08-15 11:46                       ` Prarit Bhargava
2016-08-18 10:50                       ` [tip:x86/urgent] " tip-bot for Jiri Olsa

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