Commit 800bb1c8 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jason Gunthorpe
Browse files

mm: handle multiple owners of device private pages in migrate_vma 

Add a new src_owner field to struct migrate_vma.  If the field is set,
only device private pages with page->pgmap->owner equal to that field are
migrated.  If the field is not set only "normal" pages are migrated.

Fixes: df6ad698 ("mm/device-public-memory: device memory cache coherent with CPU")
Link: https://lore.kernel.org/r/20200316193216.920734-3-hch@lst.de


Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarRalph Campbell <rcampbell@nvidia.com>
Tested-by: default avatarBharata B Rao <bharata@linux.ibm.com>
Signed-off-by: default avatarJason Gunthorpe <jgg@mellanox.com>
parent f894ddd5

arch/powerpc/kvm/book3s_hv_uvmem.c

+1 −0
Original line number Original line Diff line number Diff line
@@ -563,6 +563,7 @@ kvmppc_svm_page_out(struct vm_area_struct *vma, unsigned long start, 
	mig.end = end;

	mig.end = end;

	mig.src = &src_pfn;

	mig.src = &src_pfn;

	mig.dst = &dst_pfn;

	mig.dst = &dst_pfn;

	mig.src_owner = &kvmppc_uvmem_pgmap;





	mutex_lock(&kvm->arch.uvmem_lock);

	mutex_lock(&kvm->arch.uvmem_lock);

	/* The requested page is already paged-out, nothing to do */

	/* The requested page is already paged-out, nothing to do */

drivers/gpu/drm/nouveau/nouveau_dmem.c

+1 −0
Original line number Original line Diff line number Diff line
@@ -176,6 +176,7 @@ static vm_fault_t nouveau_dmem_migrate_to_ram(struct vm_fault *vmf) 
		.end		= vmf->address + PAGE_SIZE,

		.end		= vmf->address + PAGE_SIZE,

		.src		= &src,

		.src		= &src,

		.dst		= &dst,

		.dst		= &dst,

		.src_owner	= drm->dev,

	};

	};





	/*

	/*

include/linux/migrate.h

+8 −0
Original line number Original line Diff line number Diff line
@@ -196,6 +196,14 @@ struct migrate_vma { 
	unsigned long		npages;

	unsigned long		npages;

	unsigned long		start;

	unsigned long		start;

	unsigned long		end;

	unsigned long		end;



	/*

	 * Set to the owner value also stored in page->pgmap->owner for

	 * migrating out of device private memory.  If set only device

	 * private pages with this owner are migrated.  If not set

	 * device private pages are not migrated at all.

	 */

	void			*src_owner;

};

};





int migrate_vma_setup(struct migrate_vma *args);

int migrate_vma_setup(struct migrate_vma *args);

mm/migrate.c

+6 −3
Original line number Original line Diff line number Diff line
@@ -2241,7 +2241,7 @@ again: 
	arch_enter_lazy_mmu_mode();

	arch_enter_lazy_mmu_mode();





	for (; addr < end; addr += PAGE_SIZE, ptep++) {

	for (; addr < end; addr += PAGE_SIZE, ptep++) {

		unsigned long mpfn, pfn;

		unsigned long mpfn = 0, pfn;

		struct page *page;

		struct page *page;

		swp_entry_t entry;

		swp_entry_t entry;

		pte_t pte;

		pte_t pte;
@@ -2255,8 +2255,6 @@ again: 
		}

		}





		if (!pte_present(pte)) {

		if (!pte_present(pte)) {

			mpfn = 0;



			/*

			/*

			 * Only care about unaddressable device page special

			 * Only care about unaddressable device page special

			 * page table entry. Other special swap entries are not

			 * page table entry. Other special swap entries are not
@@ -2267,11 +2265,16 @@ again: 
				goto next;

				goto next;





			page = device_private_entry_to_page(entry);

			page = device_private_entry_to_page(entry);

			if (page->pgmap->owner != migrate->src_owner)

				goto next;



			mpfn = migrate_pfn(page_to_pfn(page)) |

			mpfn = migrate_pfn(page_to_pfn(page)) |

					MIGRATE_PFN_MIGRATE;

					MIGRATE_PFN_MIGRATE;

			if (is_write_device_private_entry(entry))

			if (is_write_device_private_entry(entry))

				mpfn |= MIGRATE_PFN_WRITE;

				mpfn |= MIGRATE_PFN_WRITE;

		} else {

		} else {

			if (migrate->src_owner)

				goto next;

			pfn = pte_pfn(pte);

			pfn = pte_pfn(pte);

			if (is_zero_pfn(pfn)) {

			if (is_zero_pfn(pfn)) {

				mpfn = MIGRATE_PFN_MIGRATE;

				mpfn = MIGRATE_PFN_MIGRATE;

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