On Wed, 28 Sep 2022 22:01:22 +1000 Alistair Popple <apopple@xxxxxxxxxx> wrote:
> @@ -1401,22 +1494,7 @@ static int dmirror_device_init(struct dmirror_device *mdevice, int id)
>
> static void dmirror_device_remove(struct dmirror_device *mdevice)
> {
> - unsigned int i;
> -
> - if (mdevice->devmem_chunks) {
> - for (i = 0; i < mdevice->devmem_count; i++) {
> - struct dmirror_chunk *devmem =
> - mdevice->devmem_chunks[i];
> -
> - memunmap_pages(&devmem->pagemap);
> - if (devmem->pagemap.type == MEMORY_DEVICE_PRIVATE)
> - release_mem_region(devmem->pagemap.range.start,
> - range_len(&devmem->pagemap.range));
> - kfree(devmem);
> - }
> - kfree(mdevice->devmem_chunks);
> - }
> -
> + dmirror_device_remove_chunks(mdevice);
> cdev_del(&mdevice->cdevice);
> }
Needed a bit or rework due to
https://lkml.kernel.org/r/20220826050631.25771-1-mpenttil@xxxxxxxxxx.
Please check my resolution.
--- a/lib/test_hmm.c~hmm-tests-add-test-for-migrate_device_range
+++ a/lib/test_hmm.c
@@ -100,6 +100,7 @@ struct dmirror {
struct dmirror_chunk {
struct dev_pagemap pagemap;
struct dmirror_device *mdevice;
+ bool remove;
};
/*
@@ -192,11 +193,15 @@ static int dmirror_fops_release(struct i
return 0;
}
+static struct dmirror_chunk *dmirror_page_to_chunk(struct page *page)
+{
+ return container_of(page->pgmap, struct dmirror_chunk, pagemap);
+}
+
static struct dmirror_device *dmirror_page_to_device(struct page *page)
{
- return container_of(page->pgmap, struct dmirror_chunk,
- pagemap)->mdevice;
+ return dmirror_page_to_chunk(page)->mdevice;
}
static int dmirror_do_fault(struct dmirror *dmirror, struct hmm_range *range)
@@ -1218,6 +1223,85 @@ static int dmirror_snapshot(struct dmirr
return ret;
}
+static void dmirror_device_evict_chunk(struct dmirror_chunk *chunk)
+{
+ unsigned long start_pfn = chunk->pagemap.range.start >> PAGE_SHIFT;
+ unsigned long end_pfn = chunk->pagemap.range.end >> PAGE_SHIFT;
+ unsigned long npages = end_pfn - start_pfn + 1;
+ unsigned long i;
+ unsigned long *src_pfns;
+ unsigned long *dst_pfns;
+
+ src_pfns = kcalloc(npages, sizeof(*src_pfns), GFP_KERNEL);
+ dst_pfns = kcalloc(npages, sizeof(*dst_pfns), GFP_KERNEL);
+
+ migrate_device_range(src_pfns, start_pfn, npages);
+ for (i = 0; i < npages; i++) {
+ struct page *dpage, *spage;
+
+ spage = migrate_pfn_to_page(src_pfns[i]);
+ if (!spage || !(src_pfns[i] & MIGRATE_PFN_MIGRATE))
+ continue;
+
+ if (WARN_ON(!is_device_private_page(spage) &&
+ !is_device_coherent_page(spage)))
+ continue;
+ spage = BACKING_PAGE(spage);
+ dpage = alloc_page(GFP_HIGHUSER_MOVABLE | __GFP_NOFAIL);
+ lock_page(dpage);
+ copy_highpage(dpage, spage);
+ dst_pfns[i] = migrate_pfn(page_to_pfn(dpage));
+ if (src_pfns[i] & MIGRATE_PFN_WRITE)
+ dst_pfns[i] |= MIGRATE_PFN_WRITE;
+ }
+ migrate_device_pages(src_pfns, dst_pfns, npages);
+ migrate_device_finalize(src_pfns, dst_pfns, npages);
+ kfree(src_pfns);
+ kfree(dst_pfns);
+}
+
+/* Removes free pages from the free list so they can't be re-allocated */
+static void dmirror_remove_free_pages(struct dmirror_chunk *devmem)
+{
+ struct dmirror_device *mdevice = devmem->mdevice;
+ struct page *page;
+
+ for (page = mdevice->free_pages; page; page = page->zone_device_data)
+ if (dmirror_page_to_chunk(page) == devmem)
+ mdevice->free_pages = page->zone_device_data;
+}
+
+static void dmirror_device_remove_chunks(struct dmirror_device *mdevice)
+{
+ unsigned int i;
+
+ mutex_lock(&mdevice->devmem_lock);
+ if (mdevice->devmem_chunks) {
+ for (i = 0; i < mdevice->devmem_count; i++) {
+ struct dmirror_chunk *devmem =
+ mdevice->devmem_chunks[i];
+
+ spin_lock(&mdevice->lock);
+ devmem->remove = true;
+ dmirror_remove_free_pages(devmem);
+ spin_unlock(&mdevice->lock);
+
+ dmirror_device_evict_chunk(devmem);
+ memunmap_pages(&devmem->pagemap);
+ if (devmem->pagemap.type == MEMORY_DEVICE_PRIVATE)
+ release_mem_region(devmem->pagemap.range.start,
+ range_len(&devmem->pagemap.range));
+ kfree(devmem);
+ }
+ mdevice->devmem_count = 0;
+ mdevice->devmem_capacity = 0;
+ mdevice->free_pages = NULL;
+ kfree(mdevice->devmem_chunks);
+ mdevice->devmem_chunks = NULL;
+ }
+ mutex_unlock(&mdevice->devmem_lock);
+}
+
static long dmirror_fops_unlocked_ioctl(struct file *filp,
unsigned int command,
unsigned long arg)
@@ -1272,6 +1356,11 @@ static long dmirror_fops_unlocked_ioctl(
ret = dmirror_snapshot(dmirror, &cmd);
break;
+ case HMM_DMIRROR_RELEASE:
+ dmirror_device_remove_chunks(dmirror->mdevice);
+ ret = 0;
+ break;
+
default:
return -EINVAL;
}
@@ -1326,9 +1415,13 @@ static void dmirror_devmem_free(struct p
mdevice = dmirror_page_to_device(page);
spin_lock(&mdevice->lock);
- mdevice->cfree++;
- page->zone_device_data = mdevice->free_pages;
- mdevice->free_pages = page;
+
+ /* Return page to our allocator if not freeing the chunk */
+ if (!dmirror_page_to_chunk(page)->remove) {
+ mdevice->cfree++;
+ page->zone_device_data = mdevice->free_pages;
+ mdevice->free_pages = page;
+ }
spin_unlock(&mdevice->lock);
}
@@ -1408,22 +1501,7 @@ static int dmirror_device_init(struct dm
static void dmirror_device_remove(struct dmirror_device *mdevice)
{
- unsigned int i;
-
- if (mdevice->devmem_chunks) {
- for (i = 0; i < mdevice->devmem_count; i++) {
- struct dmirror_chunk *devmem =
- mdevice->devmem_chunks[i];
-
- memunmap_pages(&devmem->pagemap);
- if (devmem->pagemap.type == MEMORY_DEVICE_PRIVATE)
- release_mem_region(devmem->pagemap.range.start,
- range_len(&devmem->pagemap.range));
- kfree(devmem);
- }
- kfree(mdevice->devmem_chunks);
- }
-
+ dmirror_device_remove_chunks(mdevice);
cdev_device_del(&mdevice->cdevice, &mdevice->device);
}
--- a/lib/test_hmm_uapi.h~hmm-tests-add-test-for-migrate_device_range
+++ a/lib/test_hmm_uapi.h
@@ -36,6 +36,7 @@ struct hmm_dmirror_cmd {
#define HMM_DMIRROR_SNAPSHOT _IOWR('H', 0x04, struct hmm_dmirror_cmd)
#define HMM_DMIRROR_EXCLUSIVE _IOWR('H', 0x05, struct hmm_dmirror_cmd)
#define HMM_DMIRROR_CHECK_EXCLUSIVE _IOWR('H', 0x06, struct hmm_dmirror_cmd)
+#define HMM_DMIRROR_RELEASE _IOWR('H', 0x07, struct hmm_dmirror_cmd)
/*
* Values returned in hmm_dmirror_cmd.ptr for HMM_DMIRROR_SNAPSHOT.
--- a/tools/testing/selftests/vm/hmm-tests.c~hmm-tests-add-test-for-migrate_device_range
+++ a/tools/testing/selftests/vm/hmm-tests.c
@@ -1054,6 +1054,55 @@ TEST_F(hmm, migrate_fault)
hmm_buffer_free(buffer);
}
+TEST_F(hmm, migrate_release)
+{
+ struct hmm_buffer *buffer;
+ unsigned long npages;
+ unsigned long size;
+ unsigned long i;
+ int *ptr;
+ int ret;
+
+ npages = ALIGN(HMM_BUFFER_SIZE, self->page_size) >> self->page_shift;
+ ASSERT_NE(npages, 0);
+ size = npages << self->page_shift;
+
+ buffer = malloc(sizeof(*buffer));
+ ASSERT_NE(buffer, NULL);
+
+ buffer->fd = -1;
+ buffer->size = size;
+ buffer->mirror = malloc(size);
+ ASSERT_NE(buffer->mirror, NULL);
+
+ buffer->ptr = mmap(NULL, size, PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS, buffer->fd, 0);
+ ASSERT_NE(buffer->ptr, MAP_FAILED);
+
+ /* 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_migrate_sys_to_dev(self->fd, 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);
+
+ /* Release device memory. */
+ ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_RELEASE, buffer, npages);
+ ASSERT_EQ(ret, 0);
+
+ /* Fault pages back to system memory and check them. */
+ for (i = 0, ptr = buffer->ptr; i < size / (2 * sizeof(*ptr)); ++i)
+ ASSERT_EQ(ptr[i], i);
+
+ hmm_buffer_free(buffer);
+}
+
/*
* Migrate anonymous shared memory to device private memory.
*/
_
