linux-kernel - Re: [PATCH v4 4/4] mm: Rework swap handling of zap_pte

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Message-ID: <Yg3VHr28m0739GQE@xz-m1.local>
Date:   Thu, 17 Feb 2022 12:54:54 +0800
From:   Peter Xu <peterx@...hat.com>
To:     John Hubbard <jhubbard@...dia.com>
Cc:     linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        Andrew Morton <akpm@...ux-foundation.org>,
        "Kirill A . Shutemov" <kirill@...temov.name>,
        Matthew Wilcox <willy@...radead.org>,
        Yang Shi <shy828301@...il.com>,
        Andrea Arcangeli <aarcange@...hat.com>,
        Alistair Popple <apopple@...dia.com>,
        David Hildenbrand <david@...hat.com>,
        Vlastimil Babka <vbabka@...e.cz>,
        Hugh Dickins <hughd@...gle.com>
Subject: Re: [PATCH v4 4/4] mm: Rework swap handling of zap_pte_range

On Wed, Feb 16, 2022 at 07:25:14PM -0800, John Hubbard wrote:
> On 2/16/22 1:48 AM, 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.
> 
> Maybe also mention that you reduced the code duplication in the 
> is_device_private_entry() area, by letting it fall through to the common
> pte_clear_not_present_full() at the end of the loop? Since you're listing
> the other changes, that one seems worth mentioning.

Isn't that the "we merge the pte clear operation" part? :)

I can add another sentence to it, if it looks better to you:

---8<---
Clean the code up by merging the device private/exclusive swap entry
handling with the rest, then we merge the pte clear operation too.  We do
it by letting the private/exclusive block fall through to the last call to
pte_clear_not_present_full().
---8<---

Thanks for the review,

-- 
Peter Xu