From: Christoph Hellwig <hch@lst.de>
To: Jerome Glisse <jglisse@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>,
Jason Gunthorpe <jgg@mellanox.com>,
Ben Skeggs <bskeggs@redhat.com>,
Ralph Campbell <rcampbell@nvidia.com>,
Bharata B Rao <bharata@linux.ibm.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, nouveau@lists.freedesktop.org,
dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 9/9] mm: remove the MIGRATE_PFN_WRITE flag
Date: Tue, 30 Jul 2019 07:46:33 +0200 [thread overview]
Message-ID: <20190730054633.GA28515@lst.de> (raw)
In-Reply-To: <20190729233044.GA7171@redhat.com>
On Mon, Jul 29, 2019 at 07:30:44PM -0400, Jerome Glisse wrote:
> On Mon, Jul 29, 2019 at 05:28:43PM +0300, Christoph Hellwig wrote:
> > The MIGRATE_PFN_WRITE is only used locally in migrate_vma_collect_pmd,
> > where it can be replaced with a simple boolean local variable.
> >
> > Signed-off-by: Christoph Hellwig <hch@lst.de>
>
> NAK that flag is useful, for instance a anonymous vma might have
> some of its page read only even if the vma has write permission.
>
> It seems that the code in nouveau is wrong (probably lost that
> in various rebase/rework) as this flag should be use to decide
> wether to map the device memory with write permission or not.
>
> I am traveling right now, i will investigate what happened to
> nouveau code.
We can add it back when needed pretty easily. Much of this has bitrotted
way to fast, and the pending ppc kvmhmm code doesn't need it either.
next prev parent reply other threads:[~2019-07-30 5:46 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-29 14:28 turn the hmm migrate_vma upside down Christoph Hellwig
2019-07-29 14:28 ` [PATCH 1/9] mm: turn " Christoph Hellwig
2019-07-29 23:12 ` Ralph Campbell
2019-07-29 23:43 ` Jerome Glisse
2019-07-31 1:46 ` Ralph Campbell
2019-08-01 7:42 ` Christoph Hellwig
2019-07-29 14:28 ` [PATCH 2/9] nouveau: reset dma_nr in nouveau_dmem_migrate_alloc_and_copy Christoph Hellwig
2019-07-29 23:18 ` Ralph Campbell
2019-07-29 14:28 ` [PATCH 3/9] nouveau: factor out device memory address calculation Christoph Hellwig
2019-07-29 23:21 ` Ralph Campbell
2019-07-29 14:28 ` [PATCH 4/9] nouveau: factor out dmem fence completion Christoph Hellwig
2019-07-29 23:23 ` Ralph Campbell
2019-07-29 14:28 ` [PATCH 5/9] nouveau: simplify nouveau_dmem_migrate_to_ram Christoph Hellwig
2019-07-29 23:26 ` Ralph Campbell
2019-07-31 9:57 ` Bharata B Rao
2019-08-01 7:46 ` Christoph Hellwig
2019-07-29 14:28 ` [PATCH 6/9] nouveau: simplify nouveau_dmem_migrate_vma Christoph Hellwig
2019-07-29 23:27 ` Ralph Campbell
2019-07-29 14:28 ` [PATCH 7/9] mm: remove the unused MIGRATE_PFN_ERROR flag Christoph Hellwig
2019-07-29 23:29 ` Ralph Campbell
2019-07-29 14:28 ` [PATCH 8/9] mm: remove the unused MIGRATE_PFN_DEVICE flag Christoph Hellwig
2019-07-29 23:31 ` Ralph Campbell
2019-07-29 14:28 ` [PATCH 9/9] mm: remove the MIGRATE_PFN_WRITE flag Christoph Hellwig
2019-07-29 23:30 ` Jerome Glisse
2019-07-30 5:46 ` Christoph Hellwig [this message]
2019-07-30 15:51 ` Jerome Glisse
2019-07-29 23:42 ` Ralph Campbell
2019-07-29 23:46 ` Jerome Glisse
2019-07-30 12:32 ` turn the hmm migrate_vma upside down Jason Gunthorpe
2019-07-30 13:09 ` Christoph Hellwig
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