linux-kernel - Re: [PATCH v2] mm: Don't fault around userfaultfd-registered regions on reads

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Message-ID: <20201204202155.GQ108496@xz-x1>
Date:   Fri, 4 Dec 2020 15:21:55 -0500
From:   Peter Xu <peterx@...hat.com>
To:     Andrea Arcangeli <aarcange@...hat.com>
Cc:     Hugh Dickins <hughd@...gle.com>,
        Matthew Wilcox <willy@...radead.org>,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        Andrew Morton <akpm@...ux-foundation.org>,
        Mike Rapoport <rppt@...ux.vnet.ibm.com>,
        David Hildenbrand <david@...hat.com>
Subject: Re: [PATCH v2] mm: Don't fault around userfaultfd-registered regions
 on reads

On Fri, Dec 04, 2020 at 02:37:17PM -0500, Andrea Arcangeli wrote:
> If we use _UFFD_SWP_UFFD_WP it looks much cleaner to keep it in the
> pte, not in the swp entry, since then you can use the already existing
> methods that only can take in input the pte_t (not the swp_entry_t).

Ah, I see now.  Yes it looks nicer if we don't even need swp_entry_t knowledge
to recognize the special pte.  So I'll try all these ideas and update.  Thanks,

-- 
Peter Xu