From: Peter Xu <peterx@redhat.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Linux-MM <linux-mm@kvack.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Kirill Shutemov <kirill@shutemov.name>,
Wei Zhang <wzam@amazon.com>,
Mike Rapoport <rppt@linux.vnet.ibm.com>,
Matthew Wilcox <willy@infradead.org>,
Miaohe Lin <linmiaohe@huawei.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Gal Pressman <galpress@amazon.com>, Jan Kara <jack@suse.cz>,
Jann Horn <jannh@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
Kirill Tkhai <ktkhai@virtuozzo.com>,
Mike Kravetz <mike.kravetz@oracle.com>,
Jason Gunthorpe <jgg@ziepe.ca>,
David Gibson <david@gibson.dropbear.id.au>,
Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH v2 3/4] mm: Introduce page_needs_cow_for_dma() for deciding whether cow
Date: Thu, 4 Feb 2021 14:25:56 -0500 [thread overview]
Message-ID: <20210204192556.GT6468@xz-x1> (raw)
In-Reply-To: <CAHk-=wiP8fB7R70h5MqDUFu2=nVHytsrdDKmQHmQTeYbyhifrA@mail.gmail.com>
On Thu, Feb 04, 2021 at 09:54:37AM -0800, Linus Torvalds wrote:
> On Thu, Feb 4, 2021 at 6:50 AM Peter Xu <peterx@redhat.com> wrote:
> >
> > --- a/include/linux/mm.h
> > +++ b/include/linux/mm.h
> > @@ -1291,6 +1291,27 @@ static inline bool page_maybe_dma_pinned(struct page *page)
> > GUP_PIN_COUNTING_BIAS;
> > }
> >
> > +static inline bool is_cow_mapping(vm_flags_t flags)
> > +{
> > + return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
> > +}
>
> Oh, and I just realized: moving this to <linux/mm.h> means that this
> patch could/should also get rid of
>
> - manual copy of this in mm/hugetlb.c:
>
> cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
>
> - private #define for the same thing in fs/proc/task_mmu.c
>
> #define is_cow_mapping(flags) (((flags) & (VM_SHARED |
> VM_MAYWRITE)) == VM_MAYWRITE)
>
> - manual copy in drivers/gpu/drm/vmwgfx/vmwgfx_page_dirty.c:
>
> bool is_cow_mapping =
> (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
>
> I guess it could be a later cleanup patch too, but maybe best done in
> this series just to not forget about it.
Will do in v3 if there is. Or I'll post a standalone patch to not disturb Gal
just in case he's kicked a test. Thanks,
--
Peter Xu
next prev parent reply other threads:[~2021-02-04 19:28 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-04 14:50 [PATCH v2 0/4] mm/hugetlb: Early cow on fork, and a few cleanups Peter Xu
2021-02-04 14:50 ` [PATCH v2 1/4] hugetlb: Dedup the code to add a new file_region Peter Xu
2021-02-04 14:50 ` [PATCH v2 2/4] hugetlg: Break earlier in add_reservation_in_range() when we can Peter Xu
2021-02-04 14:50 ` [PATCH v2 3/4] mm: Introduce page_needs_cow_for_dma() for deciding whether cow Peter Xu
2021-02-04 17:54 ` Linus Torvalds
2021-02-04 19:25 ` Peter Xu [this message]
2021-02-04 23:20 ` Jason Gunthorpe
2021-02-05 0:50 ` Peter Xu
2021-02-04 14:50 ` [PATCH v2 4/4] hugetlb: Do early cow when page pinned on src mm Peter Xu
2021-02-04 23:25 ` Mike Kravetz
2021-02-05 1:43 ` Peter Xu
2021-02-05 5:11 ` Mike Kravetz
2021-02-05 16:05 ` Peter Xu
[not found] ` <329ADC08-552E-423B-9230-99643B81C14A@amazon.com>
2021-02-05 15:51 ` Peter Xu
2021-02-07 9:09 ` Gal Pressman
2021-02-07 15:31 ` Peter Xu
2021-02-04 20:20 ` [PATCH v2 5/4] mm: Use is_cow_mapping() across tree where proper Peter Xu
2021-02-04 20:26 ` Linus Torvalds
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