mm/migrate: add a flags parameter to migrate_vma

The src_owner field in struct migrate_vma is being used for two purposes,
it acts as a selection filter for which types of pages are to be migrated
and it identifies device private pages owned by the caller.

Split this into separate parameters so the src_owner field can be used
just to identify device private pages owned by the caller of
migrate_vma_setup().

Rename the src_owner field to pgmap_owner to reflect it is now used only
to identify which device private pages to migrate.

Link: https://lore.kernel.org/r/20200723223004.9586-3-rcampbell@nvidia.com
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: Bharata B Rao <bharata@linux.ibm.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

diff --git a/arch/powerpc/kvm/book3s_hv_uvmem.c b/arch/powerpc/kvm/book3s_hv_uvmem.c
index 09d8119024db742f94c057d114ea2e27fcf241ca..6850bd04bcb94fcbceec2f549f39568f253cfeca 100644 (file)
--- a/arch/powerpc/kvm/book3s_hv_uvmem.c
+++ b/arch/powerpc/kvm/book3s_hv_uvmem.c
@@ -400,6 +400,7 @@ kvmppc_svm_page_in(struct vm_area_struct *vma, unsigned long start,
        mig.end = end;
        mig.src = &src_pfn;
        mig.dst = &dst_pfn;
+       mig.flags = MIGRATE_VMA_SELECT_SYSTEM;
 
        /*
         * We come here with mmap_lock write lock held just for
@@ -577,7 +578,8 @@ kvmppc_svm_page_out(struct vm_area_struct *vma, unsigned long start,
        mig.end = end;
        mig.src = &src_pfn;
        mig.dst = &dst_pfn;
-       mig.src_owner = &kvmppc_uvmem_pgmap;
+       mig.pgmap_owner = &kvmppc_uvmem_pgmap;
+       mig.flags = MIGRATE_VMA_SELECT_DEVICE_PRIVATE;
 
        mutex_lock(&kvm->arch.uvmem_lock);
        /* The requested page is already paged-out, nothing to do */

diff --git a/drivers/gpu/drm/nouveau/nouveau_dmem.c b/drivers/gpu/drm/nouveau/nouveau_dmem.c
index e5c230d9ae24ed2ccca95c4d25c6765ef26beca0..78b9e3c2a5b3d7b08dc96f6010d70574a0a552ff 100644 (file)
--- a/drivers/gpu/drm/nouveau/nouveau_dmem.c
+++ b/drivers/gpu/drm/nouveau/nouveau_dmem.c
@@ -182,7 +182,8 @@ static vm_fault_t nouveau_dmem_migrate_to_ram(struct vm_fault *vmf)
                .end            = vmf->address + PAGE_SIZE,
                .src            = &src,
                .dst            = &dst,
-               .src_owner      = drm->dev,
+               .pgmap_owner    = drm->dev,
+               .flags          = MIGRATE_VMA_SELECT_DEVICE_PRIVATE,
        };
 
        /*
@@ -615,6 +616,7 @@ nouveau_dmem_migrate_vma(struct nouveau_drm *drm,
        struct migrate_vma args = {
                .vma            = vma,
                .start          = start,
+               .flags          = MIGRATE_VMA_SELECT_SYSTEM,
        };
        unsigned long i;
        u64 *pfns;

diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index 3e546cbf03ddf6f7c5ea61e7e33c820bfbc781dd..16e03a51e5cfeda26ab950a7c8a2bacb5bce8e85 100644 (file)
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h
@@ -180,6 +180,11 @@ static inline unsigned long migrate_pfn(unsigned long pfn)
        return (pfn << MIGRATE_PFN_SHIFT) | MIGRATE_PFN_VALID;
 }
 
+enum migrate_vma_direction {
+       MIGRATE_VMA_SELECT_SYSTEM = 1 << 0,
+       MIGRATE_VMA_SELECT_DEVICE_PRIVATE = 1 << 1,
+};
+
 struct migrate_vma {
        struct vm_area_struct   *vma;
        /*
@@ -199,11 +204,11 @@ struct migrate_vma {
 
        /*
         * 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.
+        * migrating out of device private memory. The flags also need to
+        * be set to MIGRATE_VMA_SELECT_DEVICE_PRIVATE.
         */
-       void                    *src_owner;
+       void                    *pgmap_owner;
+       unsigned long           flags;
 };
 
 int migrate_vma_setup(struct migrate_vma *args);

diff --git a/lib/test_hmm.c b/lib/test_hmm.c
index 9aa577afc269669360985b59c5dc741a0ceb80ab..e78a1414f58e6dcfee45113f8172ee50201e2978 100644 (file)
--- a/lib/test_hmm.c
+++ b/lib/test_hmm.c
@@ -585,15 +585,6 @@ static void dmirror_migrate_alloc_and_copy(struct migrate_vma *args,
                 */
                spage = migrate_pfn_to_page(*src);
 
-               /*
-                * Don't migrate device private pages from our own driver or
-                * others. For our own we would do a device private memory copy
-                * not a migration and for others, we would need to fault the
-                * other device's page into system memory first.
-                */
-               if (spage && is_zone_device_page(spage))
-                       continue;
-
                dpage = dmirror_devmem_alloc_page(mdevice);
                if (!dpage)
                        continue;
@@ -702,7 +693,8 @@ static int dmirror_migrate(struct dmirror *dmirror,
                args.dst = dst_pfns;
                args.start = addr;
                args.end = next;
-               args.src_owner = NULL;
+               args.pgmap_owner = NULL;
+               args.flags = MIGRATE_VMA_SELECT_SYSTEM;
                ret = migrate_vma_setup(&args);
                if (ret)
                        goto out;
@@ -1053,7 +1045,8 @@ static vm_fault_t dmirror_devmem_fault(struct vm_fault *vmf)
        args.end = args.start + PAGE_SIZE;
        args.src = &src_pfns;
        args.dst = &dst_pfns;
-       args.src_owner = dmirror->mdevice;
+       args.pgmap_owner = dmirror->mdevice;
+       args.flags = MIGRATE_VMA_SELECT_DEVICE_PRIVATE;
 
        if (migrate_vma_setup(&args))
                return VM_FAULT_SIGBUS;

diff --git a/mm/migrate.c b/mm/migrate.c
index f3772967355861556660db86d6a5dfb59c890971..e3ea68e3a08b41e492d420e00f53c5bfaec76a41 100644 (file)
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -2287,7 +2287,9 @@ again:
                                goto next;
 
                        page = device_private_entry_to_page(entry);
-                       if (page->pgmap->owner != migrate->src_owner)
+                       if (!(migrate->flags &
+                               MIGRATE_VMA_SELECT_DEVICE_PRIVATE) ||
+                           page->pgmap->owner != migrate->pgmap_owner)
                                goto next;
 
                        mpfn = migrate_pfn(page_to_pfn(page)) |
@@ -2295,7 +2297,7 @@ again:
                        if (is_write_device_private_entry(entry))
                                mpfn |= MIGRATE_PFN_WRITE;
                } else {
-                       if (migrate->src_owner)
+                       if (!(migrate->flags & MIGRATE_VMA_SELECT_SYSTEM))
                                goto next;
                        pfn = pte_pfn(pte);
                        if (is_zero_pfn(pfn)) {