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Date: Mon, 29 Oct 2001 15:25:36 -0800 (PST)
From: Linus Torvalds <torvalds@transmeta.com>
To: Benjamin LaHaise <bcrl@redhat.com>
cc: "David S. Miller" <davem@redhat.com>, <linux-kernel@vger.kernel.org>
Subject: Re: please revert bogus patch to vmscan.c
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On Mon, 29 Oct 2001, Benjamin LaHaise wrote:
>
> I think it's far more expensive to pull a page back in from disk.

Note that _if_ the page is so often accessed that it stays in the TLB, it
won't ever hit the disk. We _will_ do a TLB invalidate when we unmap it,
and it will get re-mapped long before it's written out.

So it's more likely to result in extra soft-faults, but considering that
if the system is paging stuff out we'll almost certainly be doing enough
context switches that the thing doesn't matter.

And avoiding the extra TLB flush (for _every_ page scanned) is noticeable
according to Andrea.

		Linus

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