From: Jason Gunthorpe <jgg@ziepe.ca>
To: Christoph Hellwig <hch@lst.de>
Cc: Jerome Glisse <jglisse@redhat.com>,
Ralph Campbell <rcampbell@nvidia.com>,
Felix.Kuehling@amd.com, linux-mm@kvack.org,
John Hubbard <jhubbard@nvidia.com>,
dri-devel@lists.freedesktop.org, amd-gfx@lists.freedesktop.org,
Philip Yang <Philip.Yang@amd.com>
Subject: Re: [PATCH hmm 2/8] mm/hmm: don't free the cached pgmap while scanning
Date: Mon, 16 Mar 2020 16:23:08 -0300 [thread overview]
Message-ID: <20200316192308.GO20941@ziepe.ca> (raw)
In-Reply-To: <20200316181324.GA24533@lst.de>
On Mon, Mar 16, 2020 at 07:13:24PM +0100, Christoph Hellwig wrote:
> On Mon, Mar 16, 2020 at 03:07:13PM -0300, Jason Gunthorpe wrote:
> > I chose this to be simple without having to goto unwind it.
> >
> > So, instead like this:
>
> As ѕaid, and per the previous discussion: I think just removing the
> pgmap lookup is the right thing to do here. Something like this patch:
OK. I think I get it now.
We don't even signal that the pfn is a pgmap to the caller, so the
caller must assume the pfn is CPU memory and can be dma mapped. At
that point it doesn't matter what kind of pgmap it is.
Races here are resolved by notifiers as we can't destroy the pgmap
without triggering invalidation of the pte
So removing is the right thing to do, and the fixing for the
device_private case is closer to the hunk I just sent.
Jason
next prev parent reply other threads:[~2020-03-16 19:23 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-11 18:34 [PATCH hmm 0/8] Various error case bug fixes for hmm_range_fault() Jason Gunthorpe
2020-03-11 18:34 ` [PATCH hmm 1/8] mm/hmm: add missing unmaps of the ptep during hmm_vma_handle_pte() Jason Gunthorpe
2020-03-12 1:28 ` Ralph Campbell
2020-03-12 14:24 ` Jason Gunthorpe
2020-03-16 8:58 ` Christoph Hellwig
2020-03-11 18:35 ` [PATCH hmm 2/8] mm/hmm: don't free the cached pgmap while scanning Jason Gunthorpe
2020-03-12 1:29 ` Ralph Campbell
2020-03-16 9:02 ` Christoph Hellwig
2020-03-16 18:07 ` Jason Gunthorpe
2020-03-16 18:13 ` Christoph Hellwig
2020-03-16 19:23 ` Jason Gunthorpe [this message]
2020-03-11 18:35 ` [PATCH hmm 3/8] mm/hmm: do not call hmm_vma_walk_hole() while holding a spinlock Jason Gunthorpe
2020-03-12 1:31 ` Ralph Campbell
2020-03-12 8:54 ` Steven Price
2020-03-12 10:28 ` [PATCH] mm/hmm: Simplify hmm_vma_walk_pud slightly Steven Price
2020-03-12 14:27 ` Jason Gunthorpe
2020-03-12 14:40 ` Steven Price
2020-03-12 15:11 ` Jason Gunthorpe
2020-03-12 16:16 ` Steven Price
2020-03-12 16:37 ` Jason Gunthorpe
2020-03-12 17:02 ` Steven Price
2020-03-12 17:17 ` Jason Gunthorpe
2020-03-13 19:55 ` Jason Gunthorpe
2020-03-13 21:04 ` Matthew Wilcox
2020-03-13 22:51 ` Jason Gunthorpe
2020-03-16 9:05 ` [PATCH hmm 3/8] mm/hmm: do not call hmm_vma_walk_hole() while holding a spinlock Christoph Hellwig
2020-03-16 12:56 ` Jason Gunthorpe
2020-03-11 18:35 ` [PATCH hmm 4/8] mm/hmm: add missing pfns set to hmm_vma_walk_pmd() Jason Gunthorpe
2020-03-12 1:33 ` Ralph Campbell
2020-03-16 9:06 ` Christoph Hellwig
2020-03-11 18:35 ` [PATCH hmm 5/8] mm/hmm: add missing call to hmm_range_need_fault() before returning EFAULT Jason Gunthorpe
2020-03-12 1:34 ` Ralph Campbell
2020-03-16 9:07 ` Christoph Hellwig
2020-03-11 18:35 ` [PATCH hmm 6/8] mm/hmm: reorganize how !pte_present is handled in hmm_vma_handle_pte() Jason Gunthorpe
2020-03-12 1:36 ` Ralph Campbell
2020-03-16 9:11 ` Christoph Hellwig
2020-03-11 18:35 ` [PATCH hmm 7/8] mm/hmm: return -EFAULT when setting HMM_PFN_ERROR on requested valid pages Jason Gunthorpe
2020-03-12 1:36 ` Ralph Campbell
2020-03-12 14:35 ` Jason Gunthorpe
2020-03-16 9:12 ` Christoph Hellwig
2020-03-11 18:35 ` [PATCH hmm 8/8] mm/hmm: add missing call to hmm_pte_need_fault in HMM_PFN_SPECIAL handling Jason Gunthorpe
2020-03-12 1:38 ` Ralph Campbell
2020-03-16 9:13 ` Christoph Hellwig
2020-03-16 12:10 ` Jason Gunthorpe
2020-03-16 12:49 ` Christoph Hellwig
2020-03-16 13:04 ` Jason Gunthorpe
2020-03-16 13:12 ` Christoph Hellwig
2020-03-17 12:32 ` Christoph Hellwig
2020-03-17 12:53 ` Jason Gunthorpe
2020-03-17 13:06 ` Christoph Hellwig
2020-03-17 13:25 ` Jason Gunthorpe
2020-03-16 12:51 ` Christoph Hellwig
2020-03-12 19:33 ` [PATCH hmm 9/8] mm/hmm: do not check pmd_protnone twice in hmm_vma_handle_pmd() Jason Gunthorpe
2020-03-12 23:50 ` Ralph Campbell
2020-03-16 9:14 ` Christoph Hellwig
2020-03-16 18:25 ` [PATCH hmm 0/8] Various error case bug fixes for hmm_range_fault() Jason Gunthorpe
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