linux-kernel - Re: [PATCH 3/3] x86, extable: Handle early exceptions

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Message-ID: <4F908EA5.4060507@zytor.com>
Date:	Thu, 19 Apr 2012 15:16:05 -0700
From:	"H. Peter Anvin" <hpa@...or.com>
To:	David Daney <ddaney.cavm@...il.com>
CC:	Linus Torvalds <torvalds@...ux-foundation.org>,
	Borislav Petkov <bp@...64.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Ingo Molnar <mingo@...nel.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	David Daney <ddaney@...iumnetworks.com>
Subject: Re: [PATCH 3/3] x86, extable: Handle early exceptions

On 04/19/2012 01:17 PM, David Daney wrote:
> 
> I usually see exception table sizes on the order of 2^10 entries, so I
> have to wonder how much you really gain from an O(1) implementation.
> 

One thing that probably would give more of a boost is to use a rbtree or
similar structure to figure out *which* extable (if any) we should be
looking at; right now it looks like we linearly walk the modules, and
don't even look to see if we are inside that module before we do a
bsearch in that module's extable...

	-hpa

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