Re: [PATCH RFC v2 2/2] mm: Rework swap handling of zap_pte_range

From: John Hubbard
Date: Tue Nov 16 2021 - 03:51:36 EST

On 11/15/21 05:57, Matthew Wilcox wrote:
On Mon, Nov 15, 2021 at 09:49:51PM +0800, Peter Xu wrote:
Clean the code up by merging the device private/exclusive swap entry handling
with the rest, then we merge the pte clear operation too.

struct* page is defined in multiple places in the function, move it upward.

Is that actually a good thing? There was a time when declaring

Yes. It is a very good thing. Having multiple cases of shadowed variables
(in this case I'm using programming language terminology, or what I
remember it as, anyway) provides lots of opportunities to create
hard-to-spot bugs.

variables more locally helped compilers with liveness analysis and
register allocation. Compilers are probably smarter now. long as the above checks out, and I see from Peter's response that
we're OK.

John Hubbard