linux-kernel - Re: [patch] x86, tlb: switch cr3 in leave

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Message-ID: <1332463899.16101.158.camel@sbsiddha-desk.sc.intel.com>
Date:	Thu, 22 Mar 2012 17:51:39 -0700
From:	Suresh Siddha <suresh.b.siddha@...el.com>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
Cc:	"H. Peter Anvin" <hpa@...or.com>, Ingo Molnar <mingo@...nel.org>,
	Len Brown <lenb@...nel.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [patch] x86, tlb: switch cr3 in leave_mm() only when needed

On Thu, 2012-03-22 at 17:37 -0700, Linus Torvalds wrote:
> On Thu, Mar 22, 2012 at 5:20 PM, H. Peter Anvin <hpa@...or.com> wrote:
> >
> > Looks great to me.  Linus, do you want this one later in the window if
> > it tests out OK between now and then, or is it too late?
> 
> It's small and trivial, so it's fine. I *would* like to hear whether
> it actually makes any real difference, though. I do see "intel_idle()"
> as a big cost in idle profiles, and I assume that translates to power
> use too, but if you guys have some actual numbers, that would be even
> better.

I was reviewing this code in some other context and thought this
optimization makes sense. Unless someone beats me, I can collect some
data on Monday.

thanks,
suresh

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