linux-kernel - Re: [PATCH 0/3] TLB flush multiple pages per IPI v5

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Date:	Tue, 09 Jun 2015 09:49:13 -0700
From:	Dave Hansen <dave.hansen@...el.com>
To:	Ingo Molnar <mingo@...nel.org>, Mel Gorman <mgorman@...e.de>
CC:	Andrew Morton <akpm@...ux-foundation.org>,
	Rik van Riel <riel@...hat.com>,
	Hugh Dickins <hughd@...gle.com>,
	Minchan Kim <minchan@...nel.org>,
	Andi Kleen <andi@...stfloor.org>,
	H Peter Anvin <hpa@...or.com>, Linux-MM <linux-mm@...ck.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH 0/3] TLB flush multiple pages per IPI v5

On 06/09/2015 08:34 AM, Dave Hansen wrote:
> 2. We should measure flushing of ascending, adjacent virtual addresses
>    mapped with 4k pages since that is the normal case.  Perhaps
>    vmalloc(16MB) or something.

Now that I think about this a bit more, we really have two different
patterns here:
1. flush_tlb_mm_range() style, which is contiguous virtual address
   flushing from an unmap-style operation.
2. Mel's new try_to_unmap_one() style, which are going to be relatively
   random virtual addresses.

So, the "ascending adjacent" case is still interesting, but it wouldn't
cover Mel's new case.
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