From: Felix Kuehling <felix.kuehling@amd.com>
To: Christoph Hellwig <hch@lst.de>, Alex Sierra <alex.sierra@amd.com>
Cc: akpm@linux-foundation.org, linux-mm@kvack.org,
rcampbell@nvidia.com, linux-ext4@vger.kernel.org,
linux-xfs@vger.kernel.org, amd-gfx@lists.freedesktop.org,
dri-devel@lists.freedesktop.org, jgg@nvidia.com,
jglisse@redhat.com
Subject: Re: [PATCH v6 04/13] drm/amdkfd: add SPM support for SVM
Date: Mon, 16 Aug 2021 14:54:30 -0400 [thread overview]
Message-ID: <0ecf3253-5c77-e982-981a-b340ff705838@amd.com> (raw)
In-Reply-To: <20210815091000.GB25067@lst.de>
Am 2021-08-15 um 5:10 a.m. schrieb Christoph Hellwig:
>> @@ -880,17 +881,22 @@ int svm_migrate_init(struct amdgpu_device *adev)
>> * should remove reserved size
>> */
>> size = ALIGN(adev->gmc.real_vram_size, 2ULL << 20);
>> - res = devm_request_free_mem_region(adev->dev, &iomem_resource, size);
>> + if (xgmi_connected_to_cpu)
>> + res = lookup_resource(&iomem_resource, adev->gmc.aper_base);
>> + else
>> + res = devm_request_free_mem_region(adev->dev, &iomem_resource, size);
>> +
> Can you explain what the point of the lookup_resource is here? res->start
> is obviously identical to the start value you pass in. So this is used
> as a way to query the length, but I'm pretty sure the driver must
> already know that as it inserted the resource itself, right?
I think you're right. We only need the start and end address from
lookup_resource and we already know that anyway. It means we can drop
patch 3 from the series.
Just to be sure, we'll confirm that the end address determined by our
driver matches the one from lookup_resource (coming from the system
address map in the system BIOS). If there were a mismatch, it would
probably be a bug (in the driver or the BIOS) that we'd need to fix anyway.
>
> On a slightly higher level comment svm_migrate_init is a bit of a mess
> with all the if/else already, and with the above addressed will become
> a bit more. I think splitting it into a device private and device
> generic case would probably help people finding it to understand the code
> much better later on. Even more so with a useful comment.
I don't really see the "mess" you're talking about. Including the above,
there are only 3 conditional statements in that function that are not
error-handling related:
/* Page migration works on Vega10 or newer */
if (kfddev->device_info->asic_family < CHIP_VEGA10)
return -EINVAL;
...
if (xgmi_connected_to_cpu)
res = lookup_resource(&iomem_resource, adev->gmc.aper_base);
else
res = devm_request_free_mem_region(adev->dev, &iomem_resource, size);
...
pgmap->type = xgmi_connected_to_cpu ?
MEMORY_DEVICE_GENERIC : MEMORY_DEVICE_PRIVATE;
Regards,
Felix
next prev parent reply other threads:[~2021-08-16 18:54 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
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 [this message]
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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