Re: [PATCH hmm 0/6] Small hmm_range_fault() cleanups

From: Ralph Campbell <rcampbell@nvidia.com>
To: Jason Gunthorpe <jgg@ziepe.ca>,
	Jerome Glisse <jglisse@redhat.com>, <Felix.Kuehling@amd.com>
Cc: Philip Yang <Philip.Yang@amd.com>,
	John Hubbard <jhubbard@nvidia.com>,
	amd-gfx@lists.freedesktop.org, linux-mm@kvack.org,
	Jason Gunthorpe <jgg@mellanox.com>,
	dri-devel@lists.freedesktop.org, Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH hmm 0/6] Small hmm_range_fault() cleanups
Date: Fri, 20 Mar 2020 14:47:59 -0700	[thread overview]
Message-ID: <70d2adde-4f70-de17-fccc-d422eb994d08@nvidia.com> (raw)
In-Reply-To: <20200320164905.21722-1-jgg@ziepe.ca>


On 3/20/20 9:48 AM, Jason Gunthorpe wrote:
> From: Jason Gunthorpe <jgg@mellanox.com>
> 
> I've had these in my work queue for a bit, nothing profound here, just some
> small edits for clarity.
> 
> Ralph's hmm tester will need a small diff to work after this - which
> illustrates how setting default_flags == 0 is the same as what was called
> SNAPSHOT:
> 
> diff --git a/lib/test_hmm.c b/lib/test_hmm.c
> index 6ca953926dc13f..5f31f5b3e64cb9 100644
> --- a/lib/test_hmm.c
> +++ b/lib/test_hmm.c
> @@ -300,7 +300,7 @@ static int dmirror_range_fault(struct dmirror *dmirror,
>   
>   		range->notifier_seq = mmu_interval_read_begin(range->notifier);
>   		down_read(&mm->mmap_sem);
> -		count = hmm_range_fault(range, 0);
> +		count = hmm_range_fault(range);
>   		up_read(&mm->mmap_sem);
>   		if (count <= 0) {
>   			if (count == 0 || count == -EBUSY)
> @@ -337,8 +337,7 @@ static int dmirror_fault(struct dmirror *dmirror, unsigned long start,
>   		.flags = dmirror_hmm_flags,
>   		.values = dmirror_hmm_values,
>   		.pfn_shift = DPT_SHIFT,
> -		.pfn_flags_mask = ~(dmirror_hmm_flags[HMM_PFN_VALID] |
> -				    dmirror_hmm_flags[HMM_PFN_WRITE]),
> +		.pfn_flags_mask = 0,
>   		.default_flags = dmirror_hmm_flags[HMM_PFN_VALID] |
>   				(write ? dmirror_hmm_flags[HMM_PFN_WRITE] : 0),
>   		.dev_private_owner = dmirror->mdevice,
> @@ -872,7 +871,7 @@ static int dmirror_range_snapshot(struct dmirror *dmirror,
>   		range->notifier_seq = mmu_interval_read_begin(range->notifier);
>   
>   		down_read(&mm->mmap_sem);
> -		count = hmm_range_fault(range, HMM_FAULT_SNAPSHOT);
> +		count = hmm_range_fault(range);
>   		up_read(&mm->mmap_sem);
>   		if (count <= 0) {
>   			if (count == 0 || count == -EBUSY)
> @@ -916,7 +915,7 @@ static int dmirror_snapshot(struct dmirror *dmirror,
>   		.flags = dmirror_hmm_flags,
>   		.values = dmirror_hmm_values,
>   		.pfn_shift = DPT_SHIFT,
> -		.pfn_flags_mask = ~0ULL,
> +		.pfn_flags_mask = 0,
>   		.dev_private_owner = dmirror->mdevice,
>   	};
>   	int ret = 0;
> 
> Jason Gunthorpe (6):
>    mm/hmm: remove pgmap checking for devmap pages
>    mm/hmm: return the fault type from hmm_pte_need_fault()
>    mm/hmm: remove unused code and tidy comments
>    mm/hmm: remove HMM_FAULT_SNAPSHOT
>    mm/hmm: remove the CONFIG_TRANSPARENT_HUGEPAGE #ifdef
>    mm/hmm: use device_private_entry_to_pfn()
> 
>   Documentation/vm/hmm.rst                |  12 +-
>   drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c |   2 +-
>   drivers/gpu/drm/nouveau/nouveau_svm.c   |   2 +-
>   include/linux/hmm.h                     |  55 +-----
>   mm/hmm.c                                | 238 +++++++++---------------
>   5 files changed, 98 insertions(+), 211 deletions(-)
> 
The series looks good to me so,
Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
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