From: Will Deacon <will@kernel.org>
To: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
linux-arm-kernel@lists.infradead.org,
Catalin Marinas <catalin.marinas@arm.com>,
Jan Kara <jack@suse.cz>, Minchan Kim <minchan@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Vinayak Menon <vinmenon@codeaurora.org>,
Hugh Dickins <hughd@google.com>,
kernel-team@android.com
Subject: Re: [PATCH v2 2/3] mm: Allow architectures to request 'old' entries when prefaulting
Date: Mon, 11 Jan 2021 14:37:42 +0000 [thread overview]
Message-ID: <20210111143742.GD7642@willie-the-truck> (raw)
In-Reply-To: <20210111142533.oulduqd76mkpdkst@box>
On Mon, Jan 11, 2021 at 05:25:33PM +0300, Kirill A. Shutemov wrote:
> On Fri, Jan 08, 2021 at 05:15:16PM +0000, Will Deacon wrote:
> > diff --git a/mm/filemap.c b/mm/filemap.c
> > index c1f2dc89b8a7..0fb9d1714797 100644
> > --- a/mm/filemap.c
> > +++ b/mm/filemap.c
> > @@ -3051,14 +3051,18 @@ vm_fault_t filemap_map_pages(struct vm_fault *vmf,
> > if (!pte_none(*vmf->pte))
> > goto unlock;
> >
> > + /* We're about to handle the fault */
> > + if (vmf->address == address) {
> > + vmf->flags &= ~FAULT_FLAG_PREFAULT;
> > + ret = VM_FAULT_NOPAGE;
> > + } else {
> > + vmf->flags |= FAULT_FLAG_PREFAULT;
> > + }
> > +
>
> Do we need to restore the oririnal status of the bit once we are done?
I can certainly add that, although it doesn't look like we do that for
vmf->pte, so it's hard to tell what the rules are here. It certainly feels
odd to restore some fields but not others, as it looks like vmf->address
will be out-of-whack with vmf->pte when filemap_map_pages() returns. Am I
missing something?
Will
next prev parent reply other threads:[~2021-01-11 14:37 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-08 17:15 [PATCH v2 0/3] Create 'old' ptes for faultaround mappings on arm64 with hardware access flag Will Deacon
2021-01-08 17:15 ` [PATCH v2 1/3] mm: Cleanup faultaround and finish_fault() codepaths Will Deacon
2021-01-11 14:26 ` Kirill A. Shutemov
2021-01-11 14:27 ` Will Deacon
2021-01-08 17:15 ` [PATCH v2 2/3] mm: Allow architectures to request 'old' entries when prefaulting Will Deacon
2021-01-11 14:25 ` Kirill A. Shutemov
2021-01-11 14:37 ` Will Deacon [this message]
2021-01-11 14:47 ` Kirill A. Shutemov
2021-01-08 17:15 ` [PATCH v2 3/3] arm64: mm: Implement arch_wants_old_prefaulted_pte() Will Deacon
2021-01-08 19:34 ` [PATCH v2 0/3] Create 'old' ptes for faultaround mappings on arm64 with hardware access flag Linus Torvalds
2021-01-08 19:42 ` Linus Torvalds
2021-01-11 14:01 ` Will Deacon
2021-01-11 13:30 ` Will Deacon
2021-01-11 21:03 ` Hugh Dickins
2021-01-12 21:46 ` Will Deacon
2021-01-11 14:24 ` Kirill A. Shutemov
2021-01-11 19:25 ` Linus Torvalds
2021-01-12 21:47 ` Will Deacon
2021-01-12 21:55 ` Linus Torvalds
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