linux-kernel - Re: [RFC 4/4]x86: avoid tlbstate lock if no enough cpus

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Message-ID: <1288768330.2467.660.camel@edumazet-laptop>
Date:	Wed, 03 Nov 2010 08:12:10 +0100
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Shaohua Li <shaohua.li@...el.com>
Cc:	lkml <linux-kernel@...r.kernel.org>, Ingo Molnar <mingo@...e.hu>,
	Andi Kleen <andi@...stfloor.org>,
	"hpa@...or.com" <hpa@...or.com>
Subject: Re: [RFC 4/4]x86: avoid tlbstate lock if no enough cpus

Le mercredi 03 novembre 2010 à 15:06 +0800, Shaohua Li a écrit :
> just don't want to include the non-present cpus here. I wonder why we
> haven't a variable to record online cpu number.

What prevents a 256 cpus machine, to have 8 online cpus that all use the
same TLB vector ?

(Max 32 vectors, so 8 cpus share each vector, settled at boot time)

Forget about 'online', and think 'possible' ;)



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