Re: [PATCH v1 05/14] drm/amdkfd: ref count init for device pages
From: Felix Kuehling <felix.kuehling@amd.com>
Date: 2021-08-25 14:34:29
Also in:
amd-gfx, dri-devel, linux-mm, linux-xfs
Am 2021-08-24 um 11:48 p.m. schrieb Alex Sierra:
quoted hunk ↗ jump to hunk
Ref counter from device pages is init to zero during memmap init zone. The first time a new device page is allocated to migrate data into it, its ref counter needs to be initialized to one. Signed-off-by: Alex Sierra <redacted> --- drivers/gpu/drm/amd/amdkfd/kfd_migrate.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c index dab290a4d19d..47ee9a895cd2 100644 --- a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c +++ b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c@@ -220,7 +220,7 @@ svm_migrate_get_vram_page(struct svm_range *prange, unsigned long pfn) page = pfn_to_page(pfn); svm_range_bo_ref(prange->svm_bo); page->zone_device_data = prange->svm_bo; - get_page(page);
There is an assumption here that the page refcount is 0 because the page should be unused. I'd add a VM_BUG_ON_PAGE(page_ref_count(page), page) here to check that assumption. Regards, Felix
+ init_page_count(page); lock_page(page); }