[PATCH v3 5/6] mm/hmm/test: add self tests for THP migration

Ralph Campbell
2020-11-06T00:52:19Z

Add some basic stand alone self tests for migrating system memory to device
private memory and back.

Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
---
lib/test_hmm.c | 437 +++++++++++++++++++++----
lib/test_hmm_uapi.h | 3 +
tools/testing/selftests/vm/hmm-tests.c | 404 +++++++++++++++++++++++
3 files changed, 775 insertions(+), 69 deletions(-)

diff --git a/lib/test_hmm.c b/lib/test_hmm.c
index 80a78877bd93..456f1a90bcc3 100644
--- a/lib/test_hmm.c
+++ b/lib/test_hmm.c
@@ -66,6 +66,7 @@ struct dmirror {
struct xarray pt;
struct mmu_interval_notifier notifier;
struct mutex mutex;
+ __u64 flags;
};

/*
@@ -91,6 +92,7 @@ struct dmirror_device {
unsigned long calloc;
unsigned long cfree;
struct page *free_pages;
+ struct page *free_huge_pages;
spinlock_t lock; /* protects the above */
};

@@ -450,6 +452,7 @@ static int dmirror_write(struct dmirror *dmirror, struct hmm_dmirror_cmd *cmd)
}

static bool dmirror_allocate_chunk(struct dmirror_device *mdevice,
+ bool is_huge,
struct page **ppage)
{
struct dmirror_chunk *devmem;
@@ -503,28 +506,51 @@ static bool dmirror_allocate_chunk(struct dmirror_device *mdevice,

mutex_unlock(&mdevice->devmem_lock);

- pr_info("added new %u MB chunk (total %u chunks, %u MB) PFNs [0x%lx 0x%lx)\n",
+ pr_info("dev %u added %u MB (total %u chunks, %u MB) PFNs [0x%lx 0x%lx)\n",
+ MINOR(mdevice->cdevice.dev),
DEVMEM_CHUNK_SIZE / (1024 * 1024),
mdevice->devmem_count,
mdevice->devmem_count * (DEVMEM_CHUNK_SIZE / (1024 * 1024)),
pfn_first, pfn_last);

spin_lock(&mdevice->lock);
- for (pfn = pfn_first; pfn < pfn_last; pfn++) {
+ for (pfn = pfn_first; pfn < pfn_last; ) {
struct page *page = pfn_to_page(pfn);

+ if (is_huge && (pfn & (HPAGE_PMD_NR - 1)) == 0 &&
+ pfn + HPAGE_PMD_NR <= pfn_last) {
+ prep_transhuge_device_private_page(page);
+ page->zone_device_data = mdevice->free_huge_pages;
+ mdevice->free_huge_pages = page;
+ pfn += HPAGE_PMD_NR;
+ continue;
+ }
page->zone_device_data = mdevice->free_pages;
mdevice->free_pages = page;
+ pfn++;
}
if (ppage) {
- *ppage = mdevice->free_pages;
- mdevice->free_pages = (*ppage)->zone_device_data;
- mdevice->calloc++;
+ if (is_huge) {
+ if (!mdevice->free_huge_pages)
+ goto err_unlock;
+ *ppage = mdevice->free_huge_pages;
+ mdevice->free_huge_pages = (*ppage)->zone_device_data;
+ mdevice->calloc += thp_nr_pages(*ppage);
+ } else if (mdevice->free_pages) {
+ *ppage = mdevice->free_pages;
+ mdevice->free_pages = (*ppage)->zone_device_data;
+ mdevice->calloc++;
+ } else
+ goto err_unlock;
}
spin_unlock(&mdevice->lock);

return true;

+err_unlock:
+ spin_unlock(&mdevice->lock);
+ return false;
+
err_release:
mutex_unlock(&mdevice->devmem_lock);
release_mem_region(devmem->pagemap.range.start, range_len(&devmem->pagemap.range));
@@ -534,7 +560,8 @@ static bool dmirror_allocate_chunk(struct dmirror_device *mdevice,
return false;
}

-static struct page *dmirror_devmem_alloc_page(struct dmirror_device *mdevice)
+static struct page *dmirror_devmem_alloc_page(struct dmirror_device *mdevice,
+ bool is_huge)
{
struct page *dpage = NULL;
struct page *rpage;
@@ -549,17 +576,40 @@ static struct page *dmirror_devmem_alloc_page(struct dmirror_device *mdevice)

spin_lock(&mdevice->lock);

- if (mdevice->free_pages) {
+ if (is_huge && mdevice->free_huge_pages) {
+ dpage = mdevice->free_huge_pages;
+ mdevice->free_huge_pages = dpage->zone_device_data;
+ mdevice->calloc += thp_nr_pages(dpage);
+ spin_unlock(&mdevice->lock);
+ } else if (!is_huge && mdevice->free_pages) {
dpage = mdevice->free_pages;
mdevice->free_pages = dpage->zone_device_data;
mdevice->calloc++;
spin_unlock(&mdevice->lock);
} else {
spin_unlock(&mdevice->lock);
- if (!dmirror_allocate_chunk(mdevice, &dpage))
+ if (!dmirror_allocate_chunk(mdevice, is_huge, &dpage))
goto error;
}

+ if (is_huge) {
+ unsigned int nr_pages = thp_nr_pages(dpage);
+ unsigned int i;
+ struct page **tpage;
+
+ tpage = kmap(rpage);
+ for (i = 0; i < nr_pages; i++, tpage++) {
+ *tpage = alloc_page(GFP_HIGHUSER);
+ if (!*tpage) {
+ while (i--)
+ __free_page(*--tpage);
+ kunmap(rpage);
+ goto error;
+ }
+ }
+ kunmap(rpage);
+ }
+
dpage->zone_device_data = rpage;
get_page(dpage);
lock_page(dpage);
@@ -570,22 +620,26 @@ static struct page *dmirror_devmem_alloc_page(struct dmirror_device *mdevice)
return NULL;
}

-static void dmirror_migrate_alloc_and_copy(struct migrate_vma *args,
- struct dmirror *dmirror)
+static int dmirror_migrate_alloc_and_copy(struct migrate_vma *args,
+ struct dmirror *dmirror)
{
struct dmirror_device *mdevice = dmirror->mdevice;
const unsigned long *src = args->src;
unsigned long *dst = args->dst;
- unsigned long addr;
+ unsigned long end_pfn = args->end >> PAGE_SHIFT;
+ unsigned long pfn;

- for (addr = args->start; addr < args->end; addr += PAGE_SIZE,
- src++, dst++) {
+ for (pfn = args->start >> PAGE_SHIFT; pfn < end_pfn; ) {
struct page *spage;
struct page *dpage;
struct page *rpage;
+ bool is_huge;
+ unsigned long write;
+ struct page **tpage;
+ unsigned long endp;

if (!(*src & MIGRATE_PFN_MIGRATE))
- continue;
+ goto next;

/*
* Note that spage might be NULL which is OK since it is an
@@ -593,15 +647,39 @@ static void dmirror_migrate_alloc_and_copy(struct migrate_vma *args,
*/
spage = migrate_pfn_to_page(*src);

- dpage = dmirror_devmem_alloc_page(mdevice);
- if (!dpage)
+ /* This flag is only set if a whole huge page is migrated. */
+ is_huge = *src & MIGRATE_PFN_COMPOUND;
+ write = (*src & MIGRATE_PFN_WRITE) ? MIGRATE_PFN_WRITE : 0;
+
+ if (dmirror->flags & HMM_DMIRROR_FLAG_FAIL_ALLOC) {
+ dmirror->flags &= ~HMM_DMIRROR_FLAG_FAIL_ALLOC;
+ dpage = NULL;
+ } else
+ dpage = dmirror_devmem_alloc_page(mdevice, is_huge);
+ if (!dpage) {
+ if (!is_huge)
+ return -ENOMEM;
+ /* Try falling back to PAGE_SIZE pages. */
+ endp = pfn + HPAGE_PMD_NR;
+ while (pfn < endp) {
+ dpage = dmirror_devmem_alloc_page(mdevice,
+ false);
+ if (!dpage)
+ return -ENOMEM;
+ rpage = dpage->zone_device_data;
+ rpage->zone_device_data = dmirror;
+ *dst = migrate_pfn(page_to_pfn(dpage)) |
+ MIGRATE_PFN_LOCKED | write;
+ if (spage)
+ copy_highpage(rpage, spage++);
+ else
+ clear_highpage(rpage);
+ pfn++;
+ src++;
+ dst++;
+ }
continue;
-
- rpage = dpage->zone_device_data;
- if (spage)
- copy_highpage(rpage, spage);
- else
- clear_highpage(rpage);
+ }

/*
* Normally, a device would use the page->zone_device_data to
@@ -609,14 +687,40 @@ static void dmirror_migrate_alloc_and_copy(struct migrate_vma *args,
* the simulated device memory and that page holds the pointer
* to the mirror.
*/
+ rpage = dpage->zone_device_data;
rpage->zone_device_data = dmirror;

- *dst = migrate_pfn(page_to_pfn(dpage)) |
- MIGRATE_PFN_LOCKED;
- if ((*src & MIGRATE_PFN_WRITE) ||
- (!spage && args->vma->vm_flags & VM_WRITE))
- *dst |= MIGRATE_PFN_WRITE;
+ *dst = migrate_pfn(page_to_pfn(dpage)) | MIGRATE_PFN_LOCKED |
+ write;
+
+ if (is_huge) {
+ endp = pfn + thp_nr_pages(dpage);
+ *dst |= MIGRATE_PFN_COMPOUND;
+ tpage = kmap(rpage);
+ while (pfn < endp) {
+ if (spage)
+ copy_highpage(*tpage, spage++);
+ else
+ clear_highpage(*tpage);
+ tpage++;
+ pfn++;
+ src++;
+ dst++;
+ }
+ kunmap(rpage);
+ continue;
+ }
+
+ if (spage)
+ copy_highpage(rpage, spage);
+ else
+ clear_highpage(rpage);
+next:
+ pfn++;
+ src++;
+ dst++;
}
+ return 0;
}

static int dmirror_migrate_finalize_and_map(struct migrate_vma *args,
@@ -627,38 +731,75 @@ static int dmirror_migrate_finalize_and_map(struct migrate_vma *args,
const unsigned long *src = args->src;
const unsigned long *dst = args->dst;
unsigned long pfn;
+ int ret = 0;

/* Map the migrated pages into the device's page tables. */
mutex_lock(&dmirror->mutex);

- for (pfn = start >> PAGE_SHIFT; pfn < (end >> PAGE_SHIFT); pfn++,
- src++, dst++) {
+ for (pfn = start >> PAGE_SHIFT; pfn < (end >> PAGE_SHIFT); ) {
+ unsigned long mpfn;
struct page *dpage;
+ struct page *rpage;
void *entry;

if (!(*src & MIGRATE_PFN_MIGRATE))
- continue;
+ goto next;

- dpage = migrate_pfn_to_page(*dst);
+ mpfn = *dst;
+ dpage = migrate_pfn_to_page(mpfn);
if (!dpage)
- continue;
+ goto next;

/*
* Store the page that holds the data so the page table
* doesn't have to deal with ZONE_DEVICE private pages.
*/
- entry = dpage->zone_device_data;
- if (*dst & MIGRATE_PFN_WRITE)
+ rpage = dpage->zone_device_data;
+ if (mpfn & MIGRATE_PFN_COMPOUND) {
+ struct page **tpage;
+ unsigned long end_pfn = pfn + thp_nr_pages(dpage);
+
+ ret = 0;
+ tpage = kmap(rpage);
+ while (pfn < end_pfn) {
+ entry = *tpage;
+ if (mpfn & MIGRATE_PFN_WRITE)
+ entry = xa_tag_pointer(entry,
+ DPT_XA_TAG_WRITE);
+ entry = xa_store(&dmirror->pt, pfn, entry,
+ GFP_KERNEL);
+ if (xa_is_err(entry)) {
+ ret = xa_err(entry);
+ break;
+ }
+ tpage++;
+ pfn++;
+ src++;
+ dst++;
+ }
+ kunmap(rpage);
+ if (ret)
+ goto err;
+ continue;
+ }
+
+ entry = rpage;
+ if (mpfn & MIGRATE_PFN_WRITE)
entry = xa_tag_pointer(entry, DPT_XA_TAG_WRITE);
entry = xa_store(&dmirror->pt, pfn, entry, GFP_ATOMIC);
if (xa_is_err(entry)) {
- mutex_unlock(&dmirror->mutex);
- return xa_err(entry);
+ ret = xa_err(entry);
+ goto err;
}
+next:
+ pfn++;
+ src++;
+ dst++;
}

+err:
mutex_unlock(&dmirror->mutex);
- return 0;
+ return ret;
}

static int dmirror_migrate(struct dmirror *dmirror,
@@ -668,8 +809,8 @@ static int dmirror_migrate(struct dmirror *dmirror,
unsigned long size = cmd->npages << PAGE_SHIFT;
struct mm_struct *mm = dmirror->notifier.mm;
struct vm_area_struct *vma;
- unsigned long src_pfns[64];
- unsigned long dst_pfns[64];
+ unsigned long *src_pfns;
+ unsigned long *dst_pfns;
struct dmirror_bounce bounce;
struct migrate_vma args;
unsigned long next;
@@ -684,6 +825,17 @@ static int dmirror_migrate(struct dmirror *dmirror,
if (!mmget_not_zero(mm))
return -EINVAL;

+ src_pfns = kmalloc_array(PTRS_PER_PTE, sizeof(*src_pfns), GFP_KERNEL);
+ if (!src_pfns) {
+ ret = -ENOMEM;
+ goto out_put;
+ }
+ dst_pfns = kmalloc_array(PTRS_PER_PTE, sizeof(*dst_pfns), GFP_KERNEL);
+ if (!dst_pfns) {
+ ret = -ENOMEM;
+ goto out_free_src;
+ }
+
mmap_read_lock(mm);
for (addr = start; addr < end; addr = next) {
vma = find_vma(mm, addr);
@@ -692,7 +844,7 @@ static int dmirror_migrate(struct dmirror *dmirror,
ret = -EINVAL;
goto out;
}
- next = min(end, addr + (ARRAY_SIZE(src_pfns) << PAGE_SHIFT));
+ next = pmd_addr_end(addr, end);
if (next > vma->vm_end)
next = vma->vm_end;

@@ -702,17 +854,24 @@ static int dmirror_migrate(struct dmirror *dmirror,
args.start = addr;
args.end = next;
args.pgmap_owner = dmirror->mdevice;
- args.flags = MIGRATE_VMA_SELECT_SYSTEM;
+ args.flags = MIGRATE_VMA_SELECT_SYSTEM |
+ MIGRATE_VMA_SELECT_COMPOUND;
ret = migrate_vma_setup(&args);
if (ret)
goto out;

- dmirror_migrate_alloc_and_copy(&args, dmirror);
- migrate_vma_pages(&args);
- dmirror_migrate_finalize_and_map(&args, dmirror);
+ ret = dmirror_migrate_alloc_and_copy(&args, dmirror);
+ if (!ret) {
+ migrate_vma_pages(&args);
+ dmirror_migrate_finalize_and_map(&args, dmirror);
+ }
migrate_vma_finalize(&args);
+ if (ret)
+ goto out;
}
mmap_read_unlock(mm);
+ kfree(dst_pfns);
+ kfree(src_pfns);
mmput(mm);

/* Return the migrated data for verification. */
@@ -733,6 +892,10 @@ static int dmirror_migrate(struct dmirror *dmirror,

out:
mmap_read_unlock(mm);
+ kfree(dst_pfns);
+out_free_src:
+ kfree(src_pfns);
+out_put:
mmput(mm);
return ret;
}
@@ -953,6 +1116,11 @@ static long dmirror_fops_unlocked_ioctl(struct file *filp,
ret = dmirror_snapshot(dmirror, &cmd);
break;

+ case HMM_DMIRROR_FLAGS:
+ dmirror->flags = cmd.npages;
+ ret = 0;
+ break;
+
default:
return -EINVAL;
}
@@ -976,22 +1144,70 @@ static const struct file_operations dmirror_fops = {
static void dmirror_devmem_free(struct page *page)
{
struct page *rpage = page->zone_device_data;
+ unsigned int order = thp_order(page);
+ unsigned int nr_pages = 1U << order;
struct dmirror_device *mdevice;

- if (rpage)
+ VM_BUG_ON_PAGE(PageTail(page), page);
+
+ if (rpage) {
+ if (order) {
+ unsigned int i;
+ struct page **tpage;
+ void *kaddr;
+
+ kaddr = kmap_atomic(rpage);
+ tpage = kaddr;
+ for (i = 0; i < nr_pages; i++, tpage++)
+ __free_page(*tpage);
+ kunmap_atomic(kaddr);
+ }
__free_page(rpage);
+ }

mdevice = dmirror_page_to_device(page);

spin_lock(&mdevice->lock);
- mdevice->cfree++;
- page->zone_device_data = mdevice->free_pages;
- mdevice->free_pages = page;
+ if (order) {
+ page->zone_device_data = mdevice->free_huge_pages;
+ mdevice->free_huge_pages = page;
+ } else {
+ page->zone_device_data = mdevice->free_pages;
+ mdevice->free_pages = page;
+ }
+ mdevice->cfree += nr_pages;
spin_unlock(&mdevice->lock);
}

+static void dmirror_devmem_split(struct page *head, struct page *page)
+{
+ struct page *rpage = head->zone_device_data;
+ unsigned long i;
+ struct page **tpage;
+ void *kaddr;
+
+ page->pgmap = head->pgmap;
+
+ if (!rpage) {
+ page->zone_device_data = NULL;
+ return;
+ }
+
+ kaddr = kmap_atomic(rpage);
+ tpage = kaddr;
+ i = page - head;
+ page->zone_device_data = tpage[i];
+ if (i == 1) {
+ head->zone_device_data = tpage[0];
+ kunmap_atomic(kaddr);
+ __free_page(rpage);
+ } else
+ kunmap_atomic(kaddr);
+}
+
static vm_fault_t dmirror_devmem_fault_alloc_and_copy(struct migrate_vma *args,
- struct dmirror *dmirror)
+ struct dmirror *dmirror,
+ unsigned long fault_addr)
{
const unsigned long *src = args->src;
unsigned long *dst = args->dst;
@@ -999,25 +1215,71 @@ static vm_fault_t dmirror_devmem_fault_alloc_and_copy(struct migrate_vma *args,
unsigned long end = args->end;
unsigned long addr;

- for (addr = start; addr < end; addr += PAGE_SIZE,
- src++, dst++) {
- struct page *dpage, *spage;
+ for (addr = start; addr < end; ) {
+ struct page *spage, *dpage;
+ unsigned int order = 0;
+ unsigned int nr_pages = 1;
+ struct page **tpage;
+ unsigned int i;

spage = migrate_pfn_to_page(*src);
if (!spage || !(*src & MIGRATE_PFN_MIGRATE))
- continue;
+ goto next;
+ order = thp_order(spage);
+ nr_pages = 1U << order;
+ /* The source page is the ZONE_DEVICE private page. */
spage = spage->zone_device_data;

- dpage = alloc_page_vma(GFP_HIGHUSER_MOVABLE, args->vma, addr);
- if (!dpage)
- continue;
+ if (dmirror->flags & HMM_DMIRROR_FLAG_FAIL_ALLOC) {
+ dmirror->flags &= ~HMM_DMIRROR_FLAG_FAIL_ALLOC;
+ dpage = NULL;
+ } else if (order)
+ dpage = alloc_transhugepage(args->vma, addr);
+ else
+ dpage = alloc_pages_vma(GFP_HIGHUSER_MOVABLE, 0,
+ args->vma, addr,
+ numa_node_id(), false);
+ if (!dpage) {
+ if (!order)
+ return VM_FAULT_OOM;
+ /* Try falling back to PAGE_SIZE pages. */
+ dpage = alloc_pages_vma(GFP_HIGHUSER_MOVABLE, 0,
+ args->vma, addr,
+ numa_node_id(), false);
+ if (!dpage)
+ return VM_FAULT_OOM;
+ lock_page(dpage);
+ xa_erase(&dmirror->pt, fault_addr >> PAGE_SHIFT);
+ i = (fault_addr - start) >> PAGE_SHIFT;
+ dst[i] = migrate_pfn(page_to_pfn(dpage)) | MIGRATE_PFN_LOCKED;
+ if (*src & MIGRATE_PFN_WRITE)
+ dst[i] |= MIGRATE_PFN_WRITE;
+ tpage = kmap(spage);
+ copy_highpage(dpage, tpage[i]);
+ kunmap(spage);
+ goto next;
+ }

lock_page(dpage);
xa_erase(&dmirror->pt, addr >> PAGE_SHIFT);
- copy_highpage(dpage, spage);
*dst = migrate_pfn(page_to_pfn(dpage)) | MIGRATE_PFN_LOCKED;
if (*src & MIGRATE_PFN_WRITE)
*dst |= MIGRATE_PFN_WRITE;
+ if (order) {
+ *dst |= MIGRATE_PFN_COMPOUND;
+ tpage = kmap(spage);
+ for (i = 0; i < nr_pages; i++) {
+ copy_highpage(dpage, *tpage);
+ tpage++;
+ dpage++;
+ }
+ kunmap(spage);
+ } else
+ copy_highpage(dpage, spage);
+next:
+ addr += PAGE_SIZE << order;
+ src += nr_pages;
+ dst += nr_pages;
}
return 0;
}
@@ -1027,33 +1289,55 @@ static vm_fault_t dmirror_devmem_fault(struct vm_fault *vmf)
struct migrate_vma args;
unsigned long src_pfns;
unsigned long dst_pfns;
+ struct page *page;
struct page *rpage;
+ unsigned int order;
struct dmirror *dmirror;
vm_fault_t ret;

+ page = thp_head(vmf->page);
+ order = thp_order(page);
+
/*
* Normally, a device would use the page->zone_device_data to point to
* the mirror but here we use it to hold the page for the simulated
* device memory and that page holds the pointer to the mirror.
*/
- rpage = vmf->page->zone_device_data;
+ rpage = page->zone_device_data;
dmirror = rpage->zone_device_data;

- /* FIXME demonstrate how we can adjust migrate range */
+ if (order) {
+ args.start = vmf->address & (PAGE_MASK << order);
+ args.end = args.start + (PAGE_SIZE << order);
+ args.src = kcalloc(PTRS_PER_PTE, sizeof(*args.src),
+ GFP_KERNEL);
+ if (!args.src)
+ return VM_FAULT_OOM;
+ args.dst = kcalloc(PTRS_PER_PTE, sizeof(*args.dst),
+ GFP_KERNEL);
+ if (!args.dst) {
+ ret = VM_FAULT_OOM;
+ goto error_src;
+ }
+ } else {
+ args.start = vmf->address;
+ args.end = args.start + PAGE_SIZE;
+ args.src = &src_pfns;
+ args.dst = &dst_pfns;
+ }
args.vma = vmf->vma;
- args.start = vmf->address;
- args.end = args.start + PAGE_SIZE;
- args.src = &src_pfns;
- args.dst = &dst_pfns;
args.pgmap_owner = dmirror->mdevice;
- args.flags = MIGRATE_VMA_SELECT_DEVICE_PRIVATE;
+ args.flags = MIGRATE_VMA_SELECT_DEVICE_PRIVATE |
+ MIGRATE_VMA_SELECT_COMPOUND;

- if (migrate_vma_setup(&args))
- return VM_FAULT_SIGBUS;
+ if (migrate_vma_setup(&args)) {
+ ret = VM_FAULT_SIGBUS;
+ goto error_dst;
+ }

- ret = dmirror_devmem_fault_alloc_and_copy(&args, dmirror);
+ ret = dmirror_devmem_fault_alloc_and_copy(&args, dmirror, vmf->address);
if (ret)
- return ret;
+ goto error_fin;
migrate_vma_pages(&args);
/*
* No device finalize step is needed since
@@ -1061,12 +1345,27 @@ static vm_fault_t dmirror_devmem_fault(struct vm_fault *vmf)
* invalidated the device page table.
*/
migrate_vma_finalize(&args);
+ if (order) {
+ kfree(args.dst);
+ kfree(args.src);
+ }
return 0;
+
+error_fin:
+ migrate_vma_finalize(&args);
+error_dst:
+ if (args.dst != &dst_pfns)
+ kfree(args.dst);
+error_src:
+ if (args.src != &src_pfns)
+ kfree(args.src);
+ return ret;
}

static const struct dev_pagemap_ops dmirror_devmem_ops = {
.page_free = dmirror_devmem_free,
.migrate_to_ram = dmirror_devmem_fault,
+ .page_split = dmirror_devmem_split,
};

static int dmirror_device_init(struct dmirror_device *mdevice, int id)
@@ -1085,7 +1384,7 @@ static int dmirror_device_init(struct dmirror_device *mdevice, int id)
return ret;

/* Build a list of free ZONE_DEVICE private struct pages */
- dmirror_allocate_chunk(mdevice, NULL);
+ dmirror_allocate_chunk(mdevice, false, NULL);

return 0;
}
diff --git a/lib/test_hmm_uapi.h b/lib/test_hmm_uapi.h
index 670b4ef2a5b6..39e6ef3b67b9 100644
--- a/lib/test_hmm_uapi.h
+++ b/lib/test_hmm_uapi.h
@@ -33,6 +33,9 @@ struct hmm_dmirror_cmd {
#define HMM_DMIRROR_WRITE _IOWR('H', 0x01, struct hmm_dmirror_cmd)
#define HMM_DMIRROR_MIGRATE _IOWR('H', 0x02, struct hmm_dmirror_cmd)
#define HMM_DMIRROR_SNAPSHOT _IOWR('H', 0x03, struct hmm_dmirror_cmd)
+#define HMM_DMIRROR_FLAGS _IOWR('H', 0x04, struct hmm_dmirror_cmd)
+
+#define HMM_DMIRROR_FLAG_FAIL_ALLOC (1ULL << 0)

/*
* Values returned in hmm_dmirror_cmd.ptr for HMM_DMIRROR_SNAPSHOT.
diff --git a/tools/testing/selftests/vm/hmm-tests.c b/tools/testing/selftests/vm/hmm-tests.c
index 5d1ac691b9f4..069c3cc3c89b 100644
--- a/tools/testing/selftests/vm/hmm-tests.c
+++ b/tools/testing/selftests/vm/hmm-tests.c
@@ -1485,4 +1485,408 @@ TEST_F(hmm2, double_map)
hmm_buffer_free(buffer);
}

+/*
+ * Migrate private anonymous huge empty page.
+ */
+TEST_F(hmm, migrate_anon_huge_empty)
+{
+ struct hmm_buffer *buffer;
+ unsigned long npages;
+ unsigned long size;
+ unsigned long i;
+ void *old_ptr;
+ void *map;
+ int *ptr;
+ int ret;
+
+ size = TWOMEG;
+
+ buffer = malloc(sizeof(*buffer));
+ ASSERT_NE(buffer, NULL);
+
+ buffer->fd = -1;
+ buffer->size = 2 * size;
+ buffer->mirror = malloc(size);
+ ASSERT_NE(buffer->mirror, NULL);
+ memset(buffer->mirror, 0xFF, size);
+
+ buffer->ptr = mmap(NULL, 2 * size,
+ PROT_READ,
+ MAP_PRIVATE | MAP_ANONYMOUS,
+ buffer->fd, 0);
+ ASSERT_NE(buffer->ptr, MAP_FAILED);
+
+ npages = size >> self->page_shift;
+ map = (void *)ALIGN((uintptr_t)buffer->ptr, size);
+ ret = madvise(map, size, MADV_HUGEPAGE);
+ ASSERT_EQ(ret, 0);
+ old_ptr = buffer->ptr;
+ buffer->ptr = map;
+
+ /* Migrate memory to device. */
+ ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_MIGRATE, buffer, npages);
+ ASSERT_EQ(ret, 0);
+ ASSERT_EQ(buffer->cpages, npages);
+
+ /* Check what the device read. */
+ for (i = 0, ptr = buffer->mirror; i < size / sizeof(*ptr); ++i)
+ ASSERT_EQ(ptr[i], 0);
+
+ buffer->ptr = old_ptr;
+ hmm_buffer_free(buffer);
+}
+
+/*
+ * Migrate private anonymous huge zero page.
+ */
+TEST_F(hmm, migrate_anon_huge_zero)
+{
+ struct hmm_buffer *buffer;
+ unsigned long npages;
+ unsigned long size;
+ unsigned long i;
+ void *old_ptr;
+ void *map;
+ int *ptr;
+ int ret;
+ int val;
+
+ size = TWOMEG;
+
+ buffer = malloc(sizeof(*buffer));
+ ASSERT_NE(buffer, NULL);
+
+ buffer->fd = -1;
+ buffer->size = 2 * size;
+ buffer->mirror = malloc(size);
+ ASSERT_NE(buffer->mirror, NULL);
+ memset(buffer->mirror, 0xFF, size);
+
+ buffer->ptr = mmap(NULL, 2 * size,
+ PROT_READ,
+ MAP_PRIVATE | MAP_ANONYMOUS,
+ buffer->fd, 0);
+ ASSERT_NE(buffer->ptr, MAP_FAILED);
+
+ npages = size >> self->page_shift;
+ map = (void *)ALIGN((uintptr_t)buffer->ptr, size);
+ ret = madvise(map, size, MADV_HUGEPAGE);
+ ASSERT_EQ(ret, 0);
+ old_ptr = buffer->ptr;
+ buffer->ptr = map;
+
+ /* Initialize a read-only zero huge page. */
+ val = *(int *)buffer->ptr;
+ ASSERT_EQ(val, 0);
+
+ /* Migrate memory to device. */
+ ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_MIGRATE, buffer, npages);
+ ASSERT_EQ(ret, 0);
+ ASSERT_EQ(buffer->cpages, npages);
+
+ /* Check what the device read. */
+ for (i = 0, ptr = buffer->mirror; i < size / sizeof(*ptr); ++i)
+ ASSERT_EQ(ptr[i], 0);
+
+ /* Fault pages back to system memory and check them. */
+ for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i) {
+ ASSERT_EQ(ptr[i], 0);
+ /* If it asserts once, it probably will 500,000 times */
+ if (ptr[i] != 0)
+ break;
+ }
+
+ buffer->ptr = old_ptr;
+ hmm_buffer_free(buffer);
+}
+
+/*
+ * Migrate private anonymous huge page and free.
+ */
+TEST_F(hmm, migrate_anon_huge_free)
+{
+ struct hmm_buffer *buffer;
+ unsigned long npages;
+ unsigned long size;
+ unsigned long i;
+ void *old_ptr;
+ void *map;
+ int *ptr;
+ int ret;
+
+ size = TWOMEG;
+
+ buffer = malloc(sizeof(*buffer));
+ ASSERT_NE(buffer, NULL);
+
+ buffer->fd = -1;
+ buffer->size = 2 * size;
+ buffer->mirror = malloc(size);
+ ASSERT_NE(buffer->mirror, NULL);
+ memset(buffer->mirror, 0xFF, size);
+
+ buffer->ptr = mmap(NULL, 2 * size,
+ PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS,
+ buffer->fd, 0);
+ ASSERT_NE(buffer->ptr, MAP_FAILED);
+
+ npages = size >> self->page_shift;
+ map = (void *)ALIGN((uintptr_t)buffer->ptr, size);
+ ret = madvise(map, size, MADV_HUGEPAGE);
+ ASSERT_EQ(ret, 0);
+ old_ptr = buffer->ptr;
+ buffer->ptr = map;
+
+ /* Initialize buffer in system memory. */
+ for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i)
+ ptr[i] = i;
+
+ /* Migrate memory to device. */
+ ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_MIGRATE, buffer, npages);
+ ASSERT_EQ(ret, 0);
+ ASSERT_EQ(buffer->cpages, npages);
+
+ /* Check what the device read. */
+ for (i = 0, ptr = buffer->mirror; i < size / sizeof(*ptr); ++i)
+ ASSERT_EQ(ptr[i], i);
+
+ /* Try freeing it. */
+ ret = madvise(map, size, MADV_FREE);
+ ASSERT_EQ(ret, 0);
+
+ buffer->ptr = old_ptr;
+ hmm_buffer_free(buffer);
+}
+
+/*
+ * Migrate private anonymous huge page and fault back to sysmem.
+ */
+TEST_F(hmm, migrate_anon_huge_fault)
+{
+ struct hmm_buffer *buffer;
+ unsigned long npages;
+ unsigned long size;
+ unsigned long i;
+ void *old_ptr;
+ void *map;
+ int *ptr;
+ int ret;
+
+ size = TWOMEG;
+
+ buffer = malloc(sizeof(*buffer));
+ ASSERT_NE(buffer, NULL);
+
+ buffer->fd = -1;
+ buffer->size = 2 * size;
+ buffer->mirror = malloc(size);
+ ASSERT_NE(buffer->mirror, NULL);
+ memset(buffer->mirror, 0xFF, size);
+
+ buffer->ptr = mmap(NULL, 2 * size,
+ PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS,
+ buffer->fd, 0);
+ ASSERT_NE(buffer->ptr, MAP_FAILED);
+
+ npages = size >> self->page_shift;
+ map = (void *)ALIGN((uintptr_t)buffer->ptr, size);
+ ret = madvise(map, size, MADV_HUGEPAGE);
+ ASSERT_EQ(ret, 0);
+ old_ptr = buffer->ptr;
+ buffer->ptr = map;
+
+ /* Initialize buffer in system memory. */
+ for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i)
+ ptr[i] = i;
+
+ /* Migrate memory to device. */
+ ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_MIGRATE, buffer, npages);
+ ASSERT_EQ(ret, 0);
+ ASSERT_EQ(buffer->cpages, npages);
+
+ /* Check what the device read. */
+ for (i = 0, ptr = buffer->mirror; i < size / sizeof(*ptr); ++i)
+ ASSERT_EQ(ptr[i], i);
+
+ /* Fault pages back to system memory and check them. */
+ for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i)
+ ASSERT_EQ(ptr[i], i);
+
+ buffer->ptr = old_ptr;
+ hmm_buffer_free(buffer);
+}
+
+/*
+ * Migrate private anonymous huge page with allocation errors.
+ */
+TEST_F(hmm, migrate_anon_huge_err)
+{
+ struct hmm_buffer *buffer;
+ unsigned long npages;
+ unsigned long size;
+ unsigned long i;
+ void *old_ptr;
+ void *map;
+ int *ptr;
+ int ret;
+
+ size = TWOMEG;
+
+ buffer = malloc(sizeof(*buffer));
+ ASSERT_NE(buffer, NULL);
+
+ buffer->fd = -1;
+ buffer->size = 2 * size;
+ buffer->mirror = malloc(2 * size);
+ ASSERT_NE(buffer->mirror, NULL);
+ memset(buffer->mirror, 0xFF, 2 * size);
+
+ old_ptr = mmap(NULL, 2 * size, PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS, buffer->fd, 0);
+ ASSERT_NE(old_ptr, MAP_FAILED);
+
+ npages = size >> self->page_shift;
+ map = (void *)ALIGN((uintptr_t)old_ptr, size);
+ ret = madvise(map, size, MADV_HUGEPAGE);
+ ASSERT_EQ(ret, 0);
+ buffer->ptr = map;
+
+ /* Initialize buffer in system memory. */
+ for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i)
+ ptr[i] = i;
+
+ /* Migrate memory to device but force a THP allocation error. */
+ ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_FLAGS, buffer,
+ HMM_DMIRROR_FLAG_FAIL_ALLOC);
+ ASSERT_EQ(ret, 0);
+ ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_MIGRATE, buffer, npages);
+ ASSERT_EQ(ret, 0);
+ ASSERT_EQ(buffer->cpages, npages);
+
+ /* Check what the device read. */
+ for (i = 0, ptr = buffer->mirror; i < size / sizeof(*ptr); ++i)
+ ASSERT_EQ(ptr[i], i);
+
+ /* Try faulting back a single (PAGE_SIZE) page. */
+ ptr = buffer->ptr;
+ ASSERT_EQ(ptr[2048], 2048);
+
+ /* unmap and remap the region to reset things. */
+ ret = munmap(old_ptr, 2 * size);
+ ASSERT_EQ(ret, 0);
+ old_ptr = mmap(NULL, 2 * size, PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS, buffer->fd, 0);
+ ASSERT_NE(old_ptr, MAP_FAILED);
+ map = (void *)ALIGN((uintptr_t)old_ptr, size);
+ ret = madvise(map, size, MADV_HUGEPAGE);
+ ASSERT_EQ(ret, 0);
+ buffer->ptr = map;
+
+ /* Initialize buffer in system memory. */
+ for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i)
+ ptr[i] = i;
+
+ /* Migrate THP to device. */
+ ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_MIGRATE, buffer, npages);
+ ASSERT_EQ(ret, 0);
+ ASSERT_EQ(buffer->cpages, npages);
+
+ /*
+ * Force an allocation error when faulting back a THP resident in the
+ * device.
+ */
+ ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_FLAGS, buffer,
+ HMM_DMIRROR_FLAG_FAIL_ALLOC);
+ ASSERT_EQ(ret, 0);
+ ptr = buffer->ptr;
+ ASSERT_EQ(ptr[2048], 2048);
+
+ buffer->ptr = old_ptr;
+ hmm_buffer_free(buffer);
+}
+
+/*
+ * Migrate private anonymous huge zero page with allocation errors.
+ */
+TEST_F(hmm, migrate_anon_huge_zero_err)
+{
+ struct hmm_buffer *buffer;
+ unsigned long npages;
+ unsigned long size;
+ unsigned long i;
+ void *old_ptr;
+ void *map;
+ int *ptr;
+ int ret;
+
+ size = TWOMEG;
+
+ buffer = malloc(sizeof(*buffer));
+ ASSERT_NE(buffer, NULL);
+
+ buffer->fd = -1;
+ buffer->size = 2 * size;
+ buffer->mirror = malloc(2 * size);
+ ASSERT_NE(buffer->mirror, NULL);
+ memset(buffer->mirror, 0xFF, 2 * size);
+
+ old_ptr = mmap(NULL, 2 * size, PROT_READ,
+ MAP_PRIVATE | MAP_ANONYMOUS, buffer->fd, 0);
+ ASSERT_NE(old_ptr, MAP_FAILED);
+
+ npages = size >> self->page_shift;
+ map = (void *)ALIGN((uintptr_t)old_ptr, size);
+ ret = madvise(map, size, MADV_HUGEPAGE);
+ ASSERT_EQ(ret, 0);
+ buffer->ptr = map;
+
+ /* Migrate memory to device but force a THP allocation error. */
+ ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_FLAGS, buffer,
+ HMM_DMIRROR_FLAG_FAIL_ALLOC);
+ ASSERT_EQ(ret, 0);
+ ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_MIGRATE, buffer, npages);
+ ASSERT_EQ(ret, 0);
+ ASSERT_EQ(buffer->cpages, npages);
+
+ /* Check what the device read. */
+ for (i = 0, ptr = buffer->mirror; i < size / sizeof(*ptr); ++i)
+ ASSERT_EQ(ptr[i], 0);
+
+ /* Try faulting back a single (PAGE_SIZE) page. */
+ ptr = buffer->ptr;
+ ASSERT_EQ(ptr[2048], 0);
+
+ /* unmap and remap the region to reset things. */
+ ret = munmap(old_ptr, 2 * size);
+ ASSERT_EQ(ret, 0);
+ old_ptr = mmap(NULL, 2 * size, PROT_READ,
+ MAP_PRIVATE | MAP_ANONYMOUS, buffer->fd, 0);
+ ASSERT_NE(old_ptr, MAP_FAILED);
+ map = (void *)ALIGN((uintptr_t)old_ptr, size);
+ ret = madvise(map, size, MADV_HUGEPAGE);
+ ASSERT_EQ(ret, 0);
+ buffer->ptr = map;
+
+ /* Initialize buffer in system memory (zero THP page). */
+ ret = ptr[0];
+ ASSERT_EQ(ret, 0);
+
+ /* Migrate memory to device but force a THP allocation error. */
+ ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_FLAGS, buffer,
+ HMM_DMIRROR_FLAG_FAIL_ALLOC);
+ ASSERT_EQ(ret, 0);
+ ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_MIGRATE, buffer, npages);
+ ASSERT_EQ(ret, 0);
+ ASSERT_EQ(buffer->cpages, npages);
+
+ /* Fault the device memory back and check it. */
+ for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i)
+ ASSERT_EQ(ptr[i], 0);
+
+ buffer->ptr = old_ptr;
+ hmm_buffer_free(buffer);
+}
+
TEST_HARNESS_MAIN
--
2.20.1