From: "Thomas Hellström (VMware)" <thomas_os@shipmail.org>
To: Linus Torvalds <torvalds@linux-foundation.org>,
"Kirill A. Shutemov" <kirill@shutemov.name>
Cc: 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 19:38:31 +0200 [thread overview]
Message-ID: <2788e6e6-6916-5f95-51f5-336b8edaee2f@shipmail.org> (raw)
In-Reply-To: <CAHk-=wigUfYXiizFH6tBCH0Na=L+c=k7CgXGoZjwKg4K1rNJ2Q@mail.gmail.com>
On 9/30/19 7:12 PM, Linus Torvalds wrote:
> On Mon, Sep 30, 2019 at 6:04 AM Kirill A. Shutemov <kirill@shutemov.name> wrote:
>> 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.
> I agree that is closer, but it does make for calling that big complex
> function for every iteration step.
>
> Of course, you are right that the callback approach is problematic
> too, now that we have retpoline issues, making those very expensive.
> But at least that hopefully gets fixed some day and gets to be a rare
> problem.
>
> Matter ot taste, I guess.
>
> Linus
Matthew Wilcox suggested something similar before the pagewalk.c rewrite:
https://lore.kernel.org/lkml/20190806190937.GD30179@bombadil.infradead.org/
Still, In this case I'd opt for using the pagewalk code: In the dirty
helpers we don't ever use a struct page, but only deal with PTE entries,
same as the pagewalk code does, but not page_vma_mapped_walk(). The
underlying memory may well be IO memory.
/Thomas
next prev parent reply other threads:[~2019-09-30 21:16 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
2019-09-30 17:12 ` Linus Torvalds
2019-09-30 17:38 ` Thomas Hellström (VMware) [this message]
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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