From: Jerome Glisse <jglisse@redhat.com>
To: Christoph Hellwig <hch@lst.de>
Cc: 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 11:51:34 -0400 [thread overview]
Message-ID: <20190730155134.GA10366@redhat.com> (raw)
In-Reply-To: <20190730054633.GA28515@lst.de>
On Tue, Jul 30, 2019 at 07:46:33AM +0200, Christoph Hellwig wrote:
> 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.
Not using is a serious bug, i will investigate this friday.
Cheers,
Jérôme
next prev parent reply other threads:[~2019-07-30 15:51 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
2019-07-30 15:51 ` Jerome Glisse [this message]
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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