Re: [PATCH v6 04/13] drm/amdkfd: add SPM support for SVM
From: Christoph Hellwig <hch@lst.de>
Date: 2021-08-15 09:10:05
Also in:
amd-gfx, linux-ext4, linux-xfs
quoted hunk ↗ jump to hunk
@@ -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? 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.