From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "Thomas Hellström (VMware)" <thomas_os@shipmail.org>,
"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
dri-devel <dri-devel@lists.freedesktop.org>,
Linux-MM <linux-mm@kvack.org>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Matthew Wilcox" <willy@infradead.org>
Subject: Re: Ack to merge through DRM? WAS Re: [PATCH v2 1/5] mm: Add write-protect and clean utilities for address space ranges
Date: Mon, 30 Sep 2019 16:03:57 +0300 [thread overview]
Message-ID: <20190930130357.ye3zlkbka2jtd56a@box> (raw)
In-Reply-To: <CAHk-=whfriLqivyRtyjDPzeNr_Y3UYkC9g123Yi_yB5c8Gcmiw@mail.gmail.com>
On Fri, Sep 27, 2019 at 09:39:48AM -0700, Linus Torvalds wrote:
> On Fri, Sep 27, 2019 at 5:17 AM Kirill A. Shutemov <kirill@shutemov.name> wrote:
> >
> > > Call it "walk_page_mapping()". And talk extensively about how the
> > > locking differs a lot from the usual "walk_page_vma()" things.
> >
> > Walking mappings of a page is what rmap does. This code thas to be
> > integrated there.
>
> Well, that's very questionable.
>
> The rmap code mainly does the "page -> virtual" mapping. One page at a time.
>
> The page walker code does the "virtual -> pte" mapping. Always a whole
> range at a time.
Have you seen page_vma_mapped_walk()? I made it specifically for rmap code
to cover cases when a THP is mapped with PTEs. To me it's not a big
stretch to make it cover multiple pages too.
> So I think conceptually, mm/memory.c and unmap_mapping_range() is
> closest but I don't think it's practical to share code.
>
> And between mm/pagewalk.c and mm/rmap.c, I think the page walking has
> way more of actual practical code sharing, and is also conceptually
> closer because most of the code is about walking a range, not looking
> up the mapping of one page.
I guess it's matter of personal preferences, but page table walkers based
on callback always felt wrong to me.
--
Kirill A. Shutemov
next prev parent reply other threads:[~2019-09-30 13:04 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-26 11:55 [PATCH v2 0/5] Emulated coherent graphics memory take 2 Thomas Hellström (VMware)
2019-09-26 11:55 ` [PATCH v2 1/5] mm: Add write-protect and clean utilities for address space ranges Thomas Hellström (VMware)
2019-09-26 12:03 ` Ack to merge through DRM? WAS " Thomas Hellström (VMware)
2019-09-26 19:19 ` Linus Torvalds
2019-09-26 20:09 ` Thomas Hellström (VMware)
2019-09-26 20:16 ` Linus Torvalds
2019-09-26 20:55 ` Thomas Hellström (VMware)
2019-09-26 22:20 ` Linus Torvalds
2019-09-27 5:55 ` Thomas Hellström (VMware)
2019-09-27 9:27 ` Thomas Hellström (VMware)
2019-09-27 12:26 ` Kirill A. Shutemov
2019-09-27 12:17 ` Kirill A. Shutemov
2019-09-27 16:39 ` Linus Torvalds
2019-09-30 13:03 ` Kirill A. Shutemov [this message]
2019-09-30 17:12 ` Linus Torvalds
2019-09-30 17:38 ` Thomas Hellström (VMware)
2019-10-02 9:21 ` Thomas Hellström (VMware)
2019-10-02 13:18 ` Kirill A. Shutemov
2019-10-02 13:28 ` Thomas Hellström (VMware)
2019-09-26 11:55 ` [PATCH v2 2/5] drm/vmwgfx: Implement an infrastructure for write-coherent resources Thomas Hellström (VMware)
2019-09-26 11:55 ` [PATCH v2 3/5] drm/vmwgfx: Use an RBtree instead of linked list for MOB resources Thomas Hellström (VMware)
2019-09-26 11:55 ` [PATCH v2 4/5] drm/vmwgfx: Implement an infrastructure for read-coherent resources Thomas Hellström (VMware)
2019-09-26 11:55 ` [PATCH v2 5/5] drm/vmwgfx: Add surface dirty-tracking callbacks Thomas Hellström (VMware)
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