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From: Jerome Glisse <j.glisse@gmail.com>
To: John Hubbard <jhubbard@nvidia.com>
Cc: Christoph Hellwig <hch@lst.de>, Alex Sierra <alex.sierra@amd.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	"Kuehling, Felix" <Felix.Kuehling@amd.com>,
	linux-mm@kvack.org, Ralph Campbell <rcampbell@nvidia.com>,
	linux-ext4@vger.kernel.org, linux-xfs@vger.kernel.org,
	amd-gfx list <amd-gfx@lists.freedesktop.org>,
	Maling list - DRI developers  <dri-devel@lists.freedesktop.org>,
	jgg@nvidia.com, Jerome Glisse <jglisse@redhat.com>
Subject: Re: [PATCH v6 02/13] mm: remove extra ZONE_DEVICE struct page refcount
Date: Thu, 19 Aug 2021 23:33:50 -0700	[thread overview]
Message-ID: <CAH3drwYwFoPOmStOkimdmJds=0AnCjXviLOA3mxZPkSow3qTFA@mail.gmail.com> (raw)
In-Reply-To: <387d5f85-3d15-9a9e-2382-6ce3c14bc6d5@nvidia.com>

Note that you do not want GUP to succeed on device page, i do not see
where that is handled in the new code.

On Sun, Aug 15, 2021 at 1:40 PM John Hubbard <jhubbard@nvidia.com> wrote:
>
> On 8/15/21 8:37 AM, Christoph Hellwig wrote:
> >> diff --git a/include/linux/mm.h b/include/linux/mm.h
> >> index 8ae31622deef..d48a1f0889d1 100644
> >> --- a/include/linux/mm.h
> >> +++ b/include/linux/mm.h
> >> @@ -1218,7 +1218,7 @@ __maybe_unused struct page *try_grab_compound_head(struct page *page, int refs,
> >>   static inline __must_check bool try_get_page(struct page *page)
> >>   {
> >>      page = compound_head(page);
> >> -    if (WARN_ON_ONCE(page_ref_count(page) <= 0))
> >> +    if (WARN_ON_ONCE(page_ref_count(page) < (int)!is_zone_device_page(page)))
> >
> > Please avoid the overly long line.  In fact I'd be tempted to just not
> > bother here and keep the old, more lose check.  Especially given that
> > John has a patch ready that removes try_get_page entirely.
> >
>
> Yes. Andrew has accepted it into mmotm.
>
> Ralph's patch here was written well before my cleanup that removed
> try_grab_page() [1]. But now that we're here, if you drop this hunk then
> it will make merging easier, I think.
>
>
> [1] https://lore.kernel.org/r/20210813044133.1536842-4-jhubbard@nvidia.com
>
> thanks,
> --
> John Hubbard
> NVIDIA
>

  parent reply	other threads:[~2021-08-20  6:34 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-13  6:31 [PATCH v6 00/13] Support DEVICE_GENERIC memory in migrate_vma_* Alex Sierra
2021-08-13  6:31 ` [PATCH v6 01/13] ext4/xfs: add page refcount helper Alex Sierra
2021-08-15  9:01   ` Christoph Hellwig
2021-08-13  6:31 ` [PATCH v6 02/13] mm: remove extra ZONE_DEVICE struct page refcount Alex Sierra
2021-08-15 15:37   ` Christoph Hellwig
2021-08-15 20:40     ` John Hubbard
2021-08-16 18:56       ` Felix Kuehling
2021-08-20  6:33       ` Jerome Glisse [this message]
2021-08-18  0:01   ` Ralph Campbell
2021-08-18  0:35     ` Felix Kuehling
2021-08-18 19:28       ` Ralph Campbell
2021-08-19 18:00         ` Sierra Guiza, Alejandro (Alex)
2021-08-19 19:59           ` Felix Kuehling
2021-08-20  4:40             ` Christoph Hellwig
2021-08-20  7:17           ` Jerome Glisse
2021-08-20  4:56         ` Christoph Hellwig
2021-08-13  6:31 ` [PATCH v6 03/13] kernel: resource: lookup_resource as exported symbol Alex Sierra
2021-08-13  6:31 ` [PATCH v6 04/13] drm/amdkfd: add SPM support for SVM Alex Sierra
2021-08-15  9:10   ` Christoph Hellwig
2021-08-16 18:54     ` Felix Kuehling
2021-08-17  5:47       ` Christoph Hellwig
2021-08-13  6:31 ` [PATCH v6 05/13] drm/amdkfd: generic type as sys mem on migration to ram Alex Sierra
2021-08-15 15:38   ` Christoph Hellwig
2021-08-16 19:53     ` Sierra Guiza, Alejandro (Alex)
2021-08-16 22:06       ` Zeng, Oak
2021-08-17  0:42         ` Felix Kuehling
2021-08-17  5:49       ` Christoph Hellwig
2021-08-13  6:31 ` [PATCH v6 06/13] include/linux/mm.h: helpers to check zone device generic type Alex Sierra
2021-08-15  9:16   ` Christoph Hellwig
2021-08-13  6:31 ` [PATCH v6 07/13] mm: add generic type support to migrate_vma helpers Alex Sierra
2021-08-15  9:19   ` Christoph Hellwig
2021-08-13  6:31 ` [PATCH v6 08/13] mm: call pgmap->ops->page_free for DEVICE_GENERIC pages Alex Sierra
2021-08-15 15:40   ` Christoph Hellwig
2021-08-16 19:00     ` Felix Kuehling
2021-08-17  5:50       ` Christoph Hellwig
2021-08-17 15:44         ` Felix Kuehling
2021-08-20  5:05           ` Christoph Hellwig
2021-08-20  7:24             ` Jerome Glisse
2021-08-13  6:31 ` [PATCH v6 09/13] lib: test_hmm add ioctl to get zone device type Alex Sierra
2021-08-13  6:31 ` [PATCH v6 10/13] lib: test_hmm add module param for " Alex Sierra
2021-08-13  6:31 ` [PATCH v6 11/13] lib: add support for device generic type in test_hmm Alex Sierra
2021-08-13  6:31 ` [PATCH v6 12/13] tools: update hmm-test to support device generic type Alex Sierra
2021-08-13  6:31 ` [PATCH v6 13/13] tools: update test_hmm script to support SP config Alex Sierra

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