2022-07-15 15:06:45

by Sierra Guiza, Alejandro (Alex)

Subject: [PATCH v9 00/14] Add MEMORY_DEVICE_COHERENT for coherent device memory mapping

This is our MEMORY_DEVICE_COHERENT patch series rebased and updated
for current 5.19.0-rc6

Changes since the last version:
- Fixed problems with migration during long-term pinning in
get_user_pages
- Open coded vm_normal_lru_pages as suggested in previous code review
- Update hmm_gup_test with more get_user_pages calls, include
hmm_cow_in_device in hmm-test.

This patch series introduces MEMORY_DEVICE_COHERENT, a type of memory
owned by a device that can be mapped into CPU page tables like
MEMORY_DEVICE_GENERIC and can also be migrated like
MEMORY_DEVICE_PRIVATE.

This patch series is mostly self-contained except for a few places where
it needs to update other subsystems to handle the new memory type.

System stability and performance are not affected according to our
ongoing testing, including xfstests.

How it works: The system BIOS advertises the GPU device memory
(aka VRAM) as SPM (special purpose memory) in the UEFI system address
map.

The amdgpu driver registers the memory with devmap as
MEMORY_DEVICE_COHERENT using devm_memremap_pages. The initial user for
this hardware page migration capability is the Frontier supercomputer
project. This functionality is not AMD-specific. We expect other GPU
vendors to find this functionality useful, and possibly other hardware
types in the future.

Our test nodes in the lab are similar to the Frontier configuration,
with .5 TB of system memory plus 256 GB of device memory split across
4 GPUs, all in a single coherent address space. Page migration is
expected to improve application efficiency significantly. We will
report empirical results as they become available.

Coherent device type pages at gup are now migrated back to system
memory if they are being pinned long-term (FOLL_LONGTERM). The reason
is, that long-term pinning would interfere with the device memory
manager owning the device-coherent pages (e.g. evictions in TTM).
These series incorporate Alistair Popple patches to do this
migration from pin_user_pages() calls. hmm_gup_test has been added to
hmm-test to test different get user pages calls.

This series includes handling of device-managed anonymous pages
returned by vm_normal_pages. Although they behave like normal pages
for purposes of mapping in CPU page tables and for COW, they do not
support LRU lists, NUMA migration or THP.

We also introduced a FOLL_LRU flag that adds the same behaviour to
follow_page and related APIs, to allow callers to specify that they
expect to put pages on an LRU list.

v2:
- Rebase to latest 5.18-rc7.
- Drop patch "mm: add device coherent checker to remove migration pte"
and modify try_to_migrate_one, to let DEVICE_COHERENT pages fall
through to normal page path. Based on Alistair Popple's comment.
- Fix comment formatting.
- Reword comment in vm_normal_page about pte_devmap().
- Merge "drm/amdkfd: coherent type as sys mem on migration to ram" to
"drm/amdkfd: add SPM support for SVM".

v3:
- Rebase to latest 5.18.0.
- Patch "mm: handling Non-LRU pages returned by vm_normal_pages"
reordered.
- Add WARN_ON_ONCE for thp device coherent case.

v4:
- Rebase to latest 5.18.0
- Fix consitency between pages with FOLL_LRU flag set and pte_devmap
at follow_page_pte.

v5:
- Remove unused zone_device_type from lib/test_hmm and
selftest/vm/hmm-test.c.

v6:
- Rebase to 5.19.0-rc4
- Rename is_pinnable_page to is_longterm_pinnable_page and add a
coherent device checker.
- Add a new gup test to hmm-test to cover fast pinnable case with
FOLL_LONGTERM.

v7:
- Reorder patch series.
- Remove FOLL_LRU and check on each caller for LRU pages handling
instead.

v8:
- Add "mm: move page zone helpers into new header-specific file"
patch. The intention is to centralize all page zone helpers and keep
them independent from mm.h and memremap.h.

v9:
- Rebase to 5.19.0-rc6
- Include latest Alistair's patch
"mm/gup: migrate device coherent pages when pinning instead of failing"
with changes based on David Hildenbrand comments.
- Replace moving page zone helpers into new header-specific file.
Instead, those were moved to mmzone.h.
Patch "mm: move page zone helpers from mm.h to mmzone.h"

Alex Sierra (13):
mm: rename is_pinnable_pages to is_longterm_pinnable_pages
mm: move page zone helpers from mm.h to mmzone.h
mm: add zone device coherent type memory support
mm: handling Non-LRU pages returned by vm_normal_pages
mm: add device coherent vma selection for memory migration
drm/amdkfd: add SPM support for SVM
lib: test_hmm add ioctl to get zone device type
lib: test_hmm add module param for zone device type
lib: add support for device coherent type in test_hmm
tools: update hmm-test to support device coherent type
tools: update test_hmm script to support SP config
tools: add hmm gup tests for device coherent type
tools: add selftests to hmm for COW in device memory

Alistair Popple (1):
mm/gup: migrate device coherent pages when pinning instead of failing

drivers/gpu/drm/amd/amdkfd/kfd_migrate.c | 34 ++-
fs/proc/task_mmu.c | 2 +-
include/linux/memremap.h | 21 +-
include/linux/migrate.h | 1 +
include/linux/mm.h | 91 +-----
include/linux/mmzone.h | 80 ++++++
lib/test_hmm.c | 337 +++++++++++++++++------
lib/test_hmm_uapi.h | 19 +-
mm/gup.c | 52 +++-
mm/gup_test.c | 2 +-
mm/huge_memory.c | 2 +-
mm/hugetlb.c | 2 +-
mm/internal.h | 1 +
mm/khugepaged.c | 9 +-
mm/ksm.c | 6 +-
mm/madvise.c | 4 +-
mm/memcontrol.c | 7 +-
mm/memory-failure.c | 8 +-
mm/memory.c | 10 +-
mm/mempolicy.c | 2 +-
mm/memremap.c | 10 +
mm/migrate.c | 4 +-
mm/migrate_device.c | 80 +++++-
mm/mlock.c | 2 +-
mm/mprotect.c | 2 +-
mm/rmap.c | 5 +-
tools/testing/selftests/vm/hmm-tests.c | 311 +++++++++++++++++++--
tools/testing/selftests/vm/test_hmm.sh | 24 +-
28 files changed, 874 insertions(+), 254 deletions(-)

--
2.32.0

2022-07-15 15:06:51

by Sierra Guiza, Alejandro (Alex)

Subject: [PATCH v9 01/14] mm: rename is_pinnable_pages to is_longterm_pinnable_pages

is_pinnable_page() and folio_is_pinnable() were renamed to
is_longterm_pinnable_page() and folio_is_longterm_pinnable()
respectively. These functions are used in the FOLL_LONGTERM flag
context.

Signed-off-by: Alex Sierra <[email protected]>
Reviewed-by: David Hildenbrand <[email protected]>
---
include/linux/mm.h | 8 ++++----
mm/gup.c | 4 ++--
mm/gup_test.c | 2 +-
mm/hugetlb.c | 2 +-
4 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index cf3d0d673f6b..3b31b33bd5be 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1592,7 +1592,7 @@ static inline bool page_needs_cow_for_dma(struct vm_area_struct *vma,

/* MIGRATE_CMA and ZONE_MOVABLE do not allow pin pages */
#ifdef CONFIG_MIGRATION
-static inline bool is_pinnable_page(struct page *page)
+static inline bool is_longterm_pinnable_page(struct page *page)
{
#ifdef CONFIG_CMA
int mt = get_pageblock_migratetype(page);
@@ -1603,15 +1603,15 @@ static inline bool is_pinnable_page(struct page *page)
return !is_zone_movable_page(page) || is_zero_pfn(page_to_pfn(page));
}
#else
-static inline bool is_pinnable_page(struct page *page)
+static inline bool is_longterm_pinnable_page(struct page *page)
{
return true;
}
#endif

-static inline bool folio_is_pinnable(struct folio *folio)
+static inline bool folio_is_longterm_pinnable(struct folio *folio)
{
- return is_pinnable_page(&folio->page);
+ return is_longterm_pinnable_page(&folio->page);
}

static inline void set_page_zone(struct page *page, enum zone_type zone)
diff --git a/mm/gup.c b/mm/gup.c
index 551264407624..b65fe8bf5af4 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -133,7 +133,7 @@ struct folio *try_grab_folio(struct page *page, int refs, unsigned int flags)
* path.
*/
if (unlikely((flags & FOLL_LONGTERM) &&
- !is_pinnable_page(page)))
+ !is_longterm_pinnable_page(page)))
return NULL;

/*
@@ -1891,7 +1891,7 @@ static long check_and_migrate_movable_pages(unsigned long nr_pages,
continue;
prev_folio = folio;

- if (folio_is_pinnable(folio))
+ if (folio_is_longterm_pinnable(folio))
continue;

/*
diff --git a/mm/gup_test.c b/mm/gup_test.c
index d974dec19e1c..12b0a91767d3 100644
--- a/mm/gup_test.c
+++ b/mm/gup_test.c
@@ -53,7 +53,7 @@ static void verify_dma_pinned(unsigned int cmd, struct page **pages,
dump_page(page, "gup_test failure");
break;
} else if (cmd == PIN_LONGTERM_BENCHMARK &&
- WARN(!is_pinnable_page(page),
+ WARN(!is_longterm_pinnable_page(page),
"pages[%lu] is NOT pinnable but pinned\n",
i)) {
dump_page(page, "gup_test failure");
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index a57e1be41401..368fd33787b0 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1135,7 +1135,7 @@ static struct page *dequeue_huge_page_node_exact(struct hstate *h, int nid)

lockdep_assert_held(&hugetlb_lock);
list_for_each_entry(page, &h->hugepage_freelists[nid], lru) {
- if (pin && !is_pinnable_page(page))
+ if (pin && !is_longterm_pinnable_page(page))
continue;

if (PageHWPoison(page))
--
2.32.0

2022-07-15 15:07:00

by Sierra Guiza, Alejandro (Alex)

Subject: [PATCH v9 03/14] mm: add zone device coherent type memory support

Device memory that is cache coherent from device and CPU point of view.
This is used on platforms that have an advanced system bus (like CAPI
or CXL). Any page of a process can be migrated to such memory. However,
no one should be allowed to pin such memory so that it can always be
evicted.

Signed-off-by: Alex Sierra <[email protected]>
Acked-by: Felix Kuehling <[email protected]>
Reviewed-by: Alistair Popple <[email protected]>
[hch: rebased ontop of the refcount changes,
removed is_dev_private_or_coherent_page]
Signed-off-by: Christoph Hellwig <[email protected]>
Acked-by: David Hildenbrand <[email protected]>
---
include/linux/memremap.h | 19 +++++++++++++++++++
include/linux/mm.h | 5 ++++-
mm/memcontrol.c | 7 ++++---
mm/memory-failure.c | 8 ++++++--
mm/memremap.c | 10 ++++++++++
mm/migrate_device.c | 16 +++++++---------
mm/rmap.c | 5 +++--
7 files changed, 53 insertions(+), 17 deletions(-)

diff --git a/include/linux/memremap.h b/include/linux/memremap.h
index 77229165c914..f27b142fd3d0 100644
--- a/include/linux/memremap.h
+++ b/include/linux/memremap.h
@@ -41,6 +41,13 @@ struct vmem_altmap {
* A more complete discussion of unaddressable memory may be found in
* include/linux/hmm.h and Documentation/vm/hmm.rst.
*
+ * MEMORY_DEVICE_COHERENT:
+ * Device memory that is cache coherent from device and CPU point of view. This
+ * is used on platforms that have an advanced system bus (like CAPI or CXL). A
+ * driver can hotplug the device memory using ZONE_DEVICE and with that memory
+ * type. Any page of a process can be migrated to such memory. However no one
+ * should be allowed to pin such memory so that it can always be evicted.
+ *
* MEMORY_DEVICE_FS_DAX:
* Host memory that has similar access semantics as System RAM i.e. DMA
* coherent and supports page pinning. In support of coordinating page
@@ -61,6 +68,7 @@ struct vmem_altmap {
enum memory_type {
/* 0 is reserved to catch uninitialized type fields */
MEMORY_DEVICE_PRIVATE = 1,
+ MEMORY_DEVICE_COHERENT,
MEMORY_DEVICE_FS_DAX,
MEMORY_DEVICE_GENERIC,
MEMORY_DEVICE_PCI_P2PDMA,
@@ -150,6 +158,17 @@ static inline bool is_pci_p2pdma_page(const struct page *page)
page->pgmap->type == MEMORY_DEVICE_PCI_P2PDMA;
}

+static inline bool is_device_coherent_page(const struct page *page)
+{
+ return is_zone_device_page(page) &&
+ page->pgmap->type == MEMORY_DEVICE_COHERENT;
+}
+
+static inline bool folio_is_device_coherent(const struct folio *folio)
+{
+ return is_device_coherent_page(&folio->page);
+}
+
#ifdef CONFIG_ZONE_DEVICE
void *memremap_pages(struct dev_pagemap *pgmap, int nid);
void memunmap_pages(struct dev_pagemap *pgmap);
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 2df8c2b98d36..3ed101dfbfab 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -28,6 +28,7 @@
#include <linux/sched.h>
#include <linux/pgtable.h>
#include <linux/kasan.h>
+#include <linux/memremap.h>

struct mempolicy;
struct anon_vma;
@@ -1522,7 +1523,9 @@ static inline bool is_longterm_pinnable_page(struct page *page)
if (mt == MIGRATE_CMA || mt == MIGRATE_ISOLATE)
return false;
#endif
- return !is_zone_movable_page(page) || is_zero_pfn(page_to_pfn(page));
+ return !(is_device_coherent_page(page) ||
+ is_zone_movable_page(page) ||
+ is_zero_pfn(page_to_pfn(page)));
}
#else
static inline bool is_longterm_pinnable_page(struct page *page)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 618c366a2f07..5d37a85c67da 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -5665,8 +5665,8 @@ static int mem_cgroup_move_account(struct page *page,
* 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
* target for charge migration. if @target is not NULL, the entry is stored
* in target->ent.
- * 3(MC_TARGET_DEVICE): like MC_TARGET_PAGE but page is MEMORY_DEVICE_PRIVATE
- * (so ZONE_DEVICE page and thus not on the lru).
+ * 3(MC_TARGET_DEVICE): like MC_TARGET_PAGE but page is device memory and
+ * thus not on the lru.
* For now we such page is charge like a regular page would be as for all
* intent and purposes it is just special memory taking the place of a
* regular page.
@@ -5704,7 +5704,8 @@ static enum mc_target_type get_mctgt_type(struct vm_area_struct *vma,
*/
if (page_memcg(page) == mc.from) {
ret = MC_TARGET_PAGE;
- if (is_device_private_page(page))
+ if (is_device_private_page(page) ||
+ is_device_coherent_page(page))
ret = MC_TARGET_DEVICE;
if (target)
target->page = page;
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index da39ec8afca8..79f175eeb190 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1685,12 +1685,16 @@ static int memory_failure_dev_pagemap(unsigned long pfn, int flags,
goto unlock;
}

- if (pgmap->type == MEMORY_DEVICE_PRIVATE) {
+ switch (pgmap->type) {
+ case MEMORY_DEVICE_PRIVATE:
+ case MEMORY_DEVICE_COHERENT:
/*
- * TODO: Handle HMM pages which may need coordination
+ * TODO: Handle device pages which may need coordination
* with device-side memory.
*/
goto unlock;
+ default:
+ break;
}

/*
diff --git a/mm/memremap.c b/mm/memremap.c
index b870a659eee6..0f8f08f8a991 100644
--- a/mm/memremap.c
+++ b/mm/memremap.c
@@ -315,6 +315,16 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid)
return ERR_PTR(-EINVAL);
}
break;
+ case MEMORY_DEVICE_COHERENT:
+ if (!pgmap->ops->page_free) {
+ WARN(1, "Missing page_free method\n");
+ return ERR_PTR(-EINVAL);
+ }
+ if (!pgmap->owner) {
+ WARN(1, "Missing owner\n");
+ return ERR_PTR(-EINVAL);
+ }
+ break;
case MEMORY_DEVICE_FS_DAX:
if (IS_ENABLED(CONFIG_FS_DAX_LIMITED)) {
WARN(1, "File system DAX not supported\n");
diff --git a/mm/migrate_device.c b/mm/migrate_device.c
index 5052093d0262..a4847ad65da3 100644
--- a/mm/migrate_device.c
+++ b/mm/migrate_device.c
@@ -518,7 +518,7 @@ EXPORT_SYMBOL(migrate_vma_setup);
* handle_pte_fault()
* do_anonymous_page()
* to map in an anonymous zero page but the struct page will be a ZONE_DEVICE
- * private page.
+ * private or coherent page.
*/
static void migrate_vma_insert_page(struct migrate_vma *migrate,
unsigned long addr,
@@ -594,11 +594,8 @@ static void migrate_vma_insert_page(struct migrate_vma *migrate,
page_to_pfn(page));
entry = swp_entry_to_pte(swp_entry);
} else {
- /*
- * For now we only support migrating to un-addressable device
- * memory.
- */
- if (is_zone_device_page(page)) {
+ if (is_zone_device_page(page) &&
+ !is_device_coherent_page(page)) {
pr_warn_once("Unsupported ZONE_DEVICE page type.\n");
goto abort;
}
@@ -701,10 +698,11 @@ void migrate_vma_pages(struct migrate_vma *migrate)

mapping = page_mapping(page);

- if (is_device_private_page(newpage)) {
+ if (is_device_private_page(newpage) ||
+ is_device_coherent_page(newpage)) {
/*
- * For now only support private anonymous when migrating
- * to un-addressable device memory.
+ * For now only support anonymous memory migrating to
+ * device private or coherent memory.
*/
if (mapping) {
migrate->src[i] &= ~MIGRATE_PFN_MIGRATE;
diff --git a/mm/rmap.c b/mm/rmap.c
index 746c05acad27..d28a0ab725b6 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1972,7 +1972,7 @@ static bool try_to_migrate_one(struct folio *folio, struct vm_area_struct *vma,
/* Update high watermark before we lower rss */
update_hiwater_rss(mm);

- if (folio_is_zone_device(folio)) {
+ if (folio_is_device_private(folio)) {
unsigned long pfn = folio_pfn(folio);
swp_entry_t entry;
pte_t swp_pte;
@@ -2138,7 +2138,8 @@ void try_to_migrate(struct folio *folio, enum ttu_flags flags)
TTU_SYNC)))
return;

- if (folio_is_zone_device(folio) && !folio_is_device_private(folio))
+ if (folio_is_zone_device(folio) &&
+ (!folio_is_device_private(folio) && !folio_is_device_coherent(folio)))
return;

/*
--
2.32.0

2022-07-15 15:07:03

by Sierra Guiza, Alejandro (Alex)

Subject: [PATCH v9 06/14] mm/gup: migrate device coherent pages when pinning instead of failing

From: Alistair Popple <[email protected]>

Currently any attempts to pin a device coherent page will fail. This is
because device coherent pages need to be managed by a device driver, and
pinning them would prevent a driver from migrating them off the device.

However this is no reason to fail pinning of these pages. These are
coherent and accessible from the CPU so can be migrated just like
pinning ZONE_MOVABLE pages. So instead of failing all attempts to pin
them first try migrating them out of ZONE_DEVICE.

[hch: rebased to the split device memory checks,
moved migrate_device_page to migrate_device.c]

Signed-off-by: Alistair Popple <[email protected]>
Acked-by: Felix Kuehling <[email protected]>
Signed-off-by: Christoph Hellwig <[email protected]>
---
mm/gup.c | 50 +++++++++++++++++++++++++++++++++++++------
mm/internal.h | 1 +
mm/migrate_device.c | 52 +++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 96 insertions(+), 7 deletions(-)

diff --git a/mm/gup.c b/mm/gup.c
index b65fe8bf5af4..22b97ab61cd9 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1881,7 +1881,7 @@ static long check_and_migrate_movable_pages(unsigned long nr_pages,
unsigned long isolation_error_count = 0, i;
struct folio *prev_folio = NULL;
LIST_HEAD(movable_page_list);
- bool drain_allow = true;
+ bool drain_allow = true, coherent_pages = false;
int ret = 0;

for (i = 0; i < nr_pages; i++) {
@@ -1891,9 +1891,38 @@ static long check_and_migrate_movable_pages(unsigned long nr_pages,
continue;
prev_folio = folio;

- if (folio_is_longterm_pinnable(folio))
+ /*
+ * Device coherent pages are managed by a driver and should not
+ * be pinned indefinitely as it prevents the driver moving the
+ * page. So when trying to pin with FOLL_LONGTERM instead try
+ * to migrate the page out of device memory.
+ */
+ if (folio_is_device_coherent(folio)) {
+ /*
+ * We always want a new GUP lookup with device coherent
+ * pages.
+ */
+ pages[i] = 0;
+ coherent_pages = true;
+
+ /*
+ * Migration will fail if the page is pinned, so convert
+ * the pin on the source page to a normal reference.
+ */
+ if (gup_flags & FOLL_PIN) {
+ get_page(&folio->page);
+ unpin_user_page(&folio->page);
+ }
+
+ ret = migrate_device_coherent_page(&folio->page);
+ if (ret)
+ goto unpin_pages;
+
continue;
+ }

+ if (folio_is_longterm_pinnable(folio))
+ continue;
/*
* Try to move out any movable page before pinning the range.
*/
@@ -1919,7 +1948,8 @@ static long check_and_migrate_movable_pages(unsigned long nr_pages,
folio_nr_pages(folio));
}

- if (!list_empty(&movable_page_list) || isolation_error_count)
+ if (!list_empty(&movable_page_list) || isolation_error_count
+ || coherent_pages)
goto unpin_pages;

/*
@@ -1929,10 +1959,16 @@ static long check_and_migrate_movable_pages(unsigned long nr_pages,
return nr_pages;

unpin_pages:
- if (gup_flags & FOLL_PIN) {
- unpin_user_pages(pages, nr_pages);
- } else {
- for (i = 0; i < nr_pages; i++)
+ /*
+ * pages[i] might be NULL if any device coherent pages were found.
+ */
+ for (i = 0; i < nr_pages; i++) {
+ if (!pages[i])
+ continue;
+
+ if (gup_flags & FOLL_PIN)
+ unpin_user_page(pages[i]);
+ else
put_page(pages[i]);
}

diff --git a/mm/internal.h b/mm/internal.h
index c0f8fbe0445b..899dab512c5a 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -853,6 +853,7 @@ int numa_migrate_prep(struct page *page, struct vm_area_struct *vma,
unsigned long addr, int page_nid, int *flags);

void free_zone_device_page(struct page *page);
+int migrate_device_coherent_page(struct page *page);

/*
* mm/gup.c
diff --git a/mm/migrate_device.c b/mm/migrate_device.c
index 18bc6483f63a..7feeb447e3b9 100644
--- a/mm/migrate_device.c
+++ b/mm/migrate_device.c
@@ -686,6 +686,12 @@ void migrate_vma_pages(struct migrate_vma *migrate)
}

if (!page) {
+ /*
+ * The only time there is no vma is when called from
+ * migrate_device_coherent_page(). However this isn't
+ * called if the page could not be unmapped.
+ */
+ VM_BUG_ON(!migrate->vma);
if (!(migrate->src[i] & MIGRATE_PFN_MIGRATE))
continue;
if (!notified) {
@@ -794,3 +800,49 @@ void migrate_vma_finalize(struct migrate_vma *migrate)
}
}
EXPORT_SYMBOL(migrate_vma_finalize);
+
+/*
+ * Migrate a device coherent page back to normal memory. The caller should have
+ * a reference on page which will be copied to the new page if migration is
+ * successful or dropped on failure.
+ */
+int migrate_device_coherent_page(struct page *page)
+{
+ unsigned long src_pfn, dst_pfn = 0;
+ struct migrate_vma args;
+ struct page *dpage;
+
+ WARN_ON_ONCE(PageCompound(page));
+
+ lock_page(page);
+ src_pfn = migrate_pfn(page_to_pfn(page)) | MIGRATE_PFN_MIGRATE;
+ args.src = &src_pfn;
+ args.dst = &dst_pfn;
+ args.cpages = 1;
+ args.npages = 1;
+ args.vma = NULL;
+
+ /*
+ * We don't have a VMA and don't need to walk the page tables to find
+ * the source page. So call migrate_vma_unmap() directly to unmap the
+ * page as migrate_vma_setup() will fail if args.vma == NULL.
+ */
+ migrate_vma_unmap(&args);
+ if (!(src_pfn & MIGRATE_PFN_MIGRATE))
+ return -EBUSY;
+
+ dpage = alloc_page(GFP_USER | __GFP_NOWARN);
+ if (dpage) {
+ lock_page(dpage);
+ dst_pfn = migrate_pfn(page_to_pfn(dpage));
+ }
+
+ migrate_vma_pages(&args);
+ if (src_pfn & MIGRATE_PFN_MIGRATE)
+ copy_highpage(dpage, page);
+ migrate_vma_finalize(&args);
+
+ if (src_pfn & MIGRATE_PFN_MIGRATE)
+ return 0;
+ return -EBUSY;
+}
--
2.32.0

2022-07-15 15:07:02

by Sierra Guiza, Alejandro (Alex)

Subject: [PATCH v9 02/14] mm: move page zone helpers from mm.h to mmzone.h

[WHY]
It makes more sense to have these helpers in zone specific header
file, rather than the generic mm.h

Signed-off-by: Alex Sierra <[email protected]>
---
include/linux/memremap.h | 2 +-
include/linux/mm.h | 78 ---------------------------------------
include/linux/mmzone.h | 80 ++++++++++++++++++++++++++++++++++++++++
3 files changed, 81 insertions(+), 79 deletions(-)

diff --git a/include/linux/memremap.h b/include/linux/memremap.h
index 8af304f6b504..77229165c914 100644
--- a/include/linux/memremap.h
+++ b/include/linux/memremap.h
@@ -2,7 +2,7 @@
#ifndef _LINUX_MEMREMAP_H_
#define _LINUX_MEMREMAP_H_

-#include <linux/mm.h>
+#include <linux/mmzone.h>
#include <linux/range.h>
#include <linux/ioport.h>
#include <linux/percpu-refcount.h>
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 3b31b33bd5be..2df8c2b98d36 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1049,84 +1049,6 @@ vm_fault_t finish_mkwrite_fault(struct vm_fault *vmf);
* back into memory.
*/

-/*
- * The zone field is never updated after free_area_init_core()
- * sets it, so none of the operations on it need to be atomic.
- */
-
-/* Page flags: | [SECTION] | [NODE] | ZONE | [LAST_CPUPID] | ... | FLAGS | */
-#define SECTIONS_PGOFF ((sizeof(unsigned long)*8) - SECTIONS_WIDTH)
-#define NODES_PGOFF (SECTIONS_PGOFF - NODES_WIDTH)
-#define ZONES_PGOFF (NODES_PGOFF - ZONES_WIDTH)
-#define LAST_CPUPID_PGOFF (ZONES_PGOFF - LAST_CPUPID_WIDTH)
-#define KASAN_TAG_PGOFF (LAST_CPUPID_PGOFF - KASAN_TAG_WIDTH)
-
-/*
- * Define the bit shifts to access each section. For non-existent
- * sections we define the shift as 0; that plus a 0 mask ensures
- * the compiler will optimise away reference to them.
- */
-#define SECTIONS_PGSHIFT (SECTIONS_PGOFF * (SECTIONS_WIDTH != 0))
-#define NODES_PGSHIFT (NODES_PGOFF * (NODES_WIDTH != 0))
-#define ZONES_PGSHIFT (ZONES_PGOFF * (ZONES_WIDTH != 0))
-#define LAST_CPUPID_PGSHIFT (LAST_CPUPID_PGOFF * (LAST_CPUPID_WIDTH != 0))
-#define KASAN_TAG_PGSHIFT (KASAN_TAG_PGOFF * (KASAN_TAG_WIDTH != 0))
-
-/* NODE:ZONE or SECTION:ZONE is used to ID a zone for the buddy allocator */
-#ifdef NODE_NOT_IN_PAGE_FLAGS
-#define ZONEID_SHIFT (SECTIONS_SHIFT + ZONES_SHIFT)
-#define ZONEID_PGOFF ((SECTIONS_PGOFF < ZONES_PGOFF)? \
- SECTIONS_PGOFF : ZONES_PGOFF)
-#else
-#define ZONEID_SHIFT (NODES_SHIFT + ZONES_SHIFT)
-#define ZONEID_PGOFF ((NODES_PGOFF < ZONES_PGOFF)? \
- NODES_PGOFF : ZONES_PGOFF)
-#endif
-
-#define ZONEID_PGSHIFT (ZONEID_PGOFF * (ZONEID_SHIFT != 0))
-
-#define ZONES_MASK ((1UL << ZONES_WIDTH) - 1)
-#define NODES_MASK ((1UL << NODES_WIDTH) - 1)
-#define SECTIONS_MASK ((1UL << SECTIONS_WIDTH) - 1)
-#define LAST_CPUPID_MASK ((1UL << LAST_CPUPID_SHIFT) - 1)
-#define KASAN_TAG_MASK ((1UL << KASAN_TAG_WIDTH) - 1)
-#define ZONEID_MASK ((1UL << ZONEID_SHIFT) - 1)
-
-static inline enum zone_type page_zonenum(const struct page *page)
-{
- ASSERT_EXCLUSIVE_BITS(page->flags, ZONES_MASK << ZONES_PGSHIFT);
- return (page->flags >> ZONES_PGSHIFT) & ZONES_MASK;
-}
-
-static inline enum zone_type folio_zonenum(const struct folio *folio)
-{
- return page_zonenum(&folio->page);
-}
-
-#ifdef CONFIG_ZONE_DEVICE
-static inline bool is_zone_device_page(const struct page *page)
-{
- return page_zonenum(page) == ZONE_DEVICE;
-}
-extern void memmap_init_zone_device(struct zone *, unsigned long,
- unsigned long, struct dev_pagemap *);
-#else
-static inline bool is_zone_device_page(const struct page *page)
-{
- return false;
-}
-#endif
-
-static inline bool folio_is_zone_device(const struct folio *folio)
-{
- return is_zone_device_page(&folio->page);
-}
-
-static inline bool is_zone_movable_page(const struct page *page)
-{
- return page_zonenum(page) == ZONE_MOVABLE;
-}
-
#if defined(CONFIG_ZONE_DEVICE) && defined(CONFIG_FS_DAX)
DECLARE_STATIC_KEY_FALSE(devmap_managed_key);

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index aab70355d64f..47fc41f43c48 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -730,6 +730,86 @@ static inline bool zone_is_empty(struct zone *zone)
return zone->spanned_pages == 0;
}

+#ifndef BUILD_VDSO32_64
+/*
+ * The zone field is never updated after free_area_init_core()
+ * sets it, so none of the operations on it need to be atomic.
+ */
+
+/* Page flags: | [SECTION] | [NODE] | ZONE | [LAST_CPUPID] | ... | FLAGS | */
+#define SECTIONS_PGOFF ((sizeof(unsigned long)*8) - SECTIONS_WIDTH)
+#define NODES_PGOFF (SECTIONS_PGOFF - NODES_WIDTH)
+#define ZONES_PGOFF (NODES_PGOFF - ZONES_WIDTH)
+#define LAST_CPUPID_PGOFF (ZONES_PGOFF - LAST_CPUPID_WIDTH)
+#define KASAN_TAG_PGOFF (LAST_CPUPID_PGOFF - KASAN_TAG_WIDTH)
+
+/*
+ * Define the bit shifts to access each section. For non-existent
+ * sections we define the shift as 0; that plus a 0 mask ensures
+ * the compiler will optimise away reference to them.
+ */
+#define SECTIONS_PGSHIFT (SECTIONS_PGOFF * (SECTIONS_WIDTH != 0))
+#define NODES_PGSHIFT (NODES_PGOFF * (NODES_WIDTH != 0))
+#define ZONES_PGSHIFT (ZONES_PGOFF * (ZONES_WIDTH != 0))
+#define LAST_CPUPID_PGSHIFT (LAST_CPUPID_PGOFF * (LAST_CPUPID_WIDTH != 0))
+#define KASAN_TAG_PGSHIFT (KASAN_TAG_PGOFF * (KASAN_TAG_WIDTH != 0))
+
+/* NODE:ZONE or SECTION:ZONE is used to ID a zone for the buddy allocator */
+#ifdef NODE_NOT_IN_PAGE_FLAGS
+#define ZONEID_SHIFT (SECTIONS_SHIFT + ZONES_SHIFT)
+#define ZONEID_PGOFF ((SECTIONS_PGOFF < ZONES_PGOFF) ? \
+ SECTIONS_PGOFF : ZONES_PGOFF)
+#else
+#define ZONEID_SHIFT (NODES_SHIFT + ZONES_SHIFT)
+#define ZONEID_PGOFF ((NODES_PGOFF < ZONES_PGOFF) ? \
+ NODES_PGOFF : ZONES_PGOFF)
+#endif
+
+#define ZONEID_PGSHIFT (ZONEID_PGOFF * (ZONEID_SHIFT != 0))
+
+#define ZONES_MASK ((1UL << ZONES_WIDTH) - 1)
+#define NODES_MASK ((1UL << NODES_WIDTH) - 1)
+#define SECTIONS_MASK ((1UL << SECTIONS_WIDTH) - 1)
+#define LAST_CPUPID_MASK ((1UL << LAST_CPUPID_SHIFT) - 1)
+#define KASAN_TAG_MASK ((1UL << KASAN_TAG_WIDTH) - 1)
+#define ZONEID_MASK ((1UL << ZONEID_SHIFT) - 1)
+
+static inline enum zone_type page_zonenum(const struct page *page)
+{
+ ASSERT_EXCLUSIVE_BITS(page->flags, ZONES_MASK << ZONES_PGSHIFT);
+ return (page->flags >> ZONES_PGSHIFT) & ZONES_MASK;
+}
+
+static inline enum zone_type folio_zonenum(const struct folio *folio)
+{
+ return page_zonenum(&folio->page);
+}
+
+#ifdef CONFIG_ZONE_DEVICE
+static inline bool is_zone_device_page(const struct page *page)
+{
+ return page_zonenum(page) == ZONE_DEVICE;
+}
+extern void memmap_init_zone_device(struct zone *, unsigned long,
+ unsigned long, struct dev_pagemap *);
+#else
+static inline bool is_zone_device_page(const struct page *page)
+{
+ return false;
+}
+#endif
+
+static inline bool folio_is_zone_device(const struct folio *folio)
+{
+ return is_zone_device_page(&folio->page);
+}
+
+static inline bool is_zone_movable_page(const struct page *page)
+{
+ return page_zonenum(page) == ZONE_MOVABLE;
+}
+#endif
+
/*
* Return true if [start_pfn, start_pfn + nr_pages) range has a non-empty
* intersection with the given zone
--
2.32.0

2022-07-15 15:07:04

by Sierra Guiza, Alejandro (Alex)

Subject: [PATCH v9 05/14] mm: add device coherent vma selection for memory migration

This case is used to migrate pages from device memory, back to system
memory. Device coherent type memory is cache coherent from device and CPU
point of view.

Signed-off-by: Alex Sierra <[email protected]>
Acked-by: Felix Kuehling <[email protected]>
Reviewed-by: Alistair Poppple <[email protected]>
Signed-off-by: Christoph Hellwig <[email protected]>
Reviewed-by: David Hildenbrand <[email protected]>
---
include/linux/migrate.h | 1 +
mm/migrate_device.c | 12 +++++++++---
2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index 069a89e847f3..b84908debe5c 100644
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h
@@ -148,6 +148,7 @@ static inline unsigned long migrate_pfn(unsigned long pfn)
enum migrate_vma_direction {
MIGRATE_VMA_SELECT_SYSTEM = 1 << 0,
MIGRATE_VMA_SELECT_DEVICE_PRIVATE = 1 << 1,
+ MIGRATE_VMA_SELECT_DEVICE_COHERENT = 1 << 2,
};

struct migrate_vma {
diff --git a/mm/migrate_device.c b/mm/migrate_device.c
index a4847ad65da3..18bc6483f63a 100644
--- a/mm/migrate_device.c
+++ b/mm/migrate_device.c
@@ -148,15 +148,21 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
if (is_writable_device_private_entry(entry))
mpfn |= MIGRATE_PFN_WRITE;
} else {
- if (!(migrate->flags & MIGRATE_VMA_SELECT_SYSTEM))
- goto next;
pfn = pte_pfn(pte);
- if (is_zero_pfn(pfn)) {
+ if (is_zero_pfn(pfn) &&
+ (migrate->flags & MIGRATE_VMA_SELECT_SYSTEM)) {
mpfn = MIGRATE_PFN_MIGRATE;
migrate->cpages++;
goto next;
}
page = vm_normal_page(migrate->vma, addr, pte);
+ if (page && !is_zone_device_page(page) &&
+ !(migrate->flags & MIGRATE_VMA_SELECT_SYSTEM))
+ goto next;
+ else if (page && is_device_coherent_page(page) &&
+ (!(migrate->flags & MIGRATE_VMA_SELECT_DEVICE_COHERENT) ||
+ page->pgmap->owner != migrate->pgmap_owner))
+ goto next;
mpfn = migrate_pfn(pfn) | MIGRATE_PFN_MIGRATE;
mpfn |= pte_write(pte) ? MIGRATE_PFN_WRITE : 0;
}
--
2.32.0

2022-07-15 15:07:12

by Sierra Guiza, Alejandro (Alex)

Subject: [PATCH v9 04/14] mm: handling Non-LRU pages returned by vm_normal_pages

With DEVICE_COHERENT, we'll soon have vm_normal_pages() return
device-managed anonymous pages that are not LRU pages. Although they
behave like normal pages for purposes of mapping in CPU page, and for
COW. They do not support LRU lists, NUMA migration or THP.

Callers to follow_page() currently don't expect ZONE_DEVICE pages,
however, with DEVICE_COHERENT we might now return ZONE_DEVICE. Check
for ZONE_DEVICE pages in applicable users of follow_page() as well.

Signed-off-by: Alex Sierra <[email protected]>
Acked-by: Felix Kuehling <[email protected]> (v2)
Reviewed-by: Alistair Popple <[email protected]> (v6)
---
fs/proc/task_mmu.c | 2 +-
mm/huge_memory.c | 2 +-
mm/khugepaged.c | 9 ++++++---
mm/ksm.c | 6 +++---
mm/madvise.c | 4 ++--
mm/memory.c | 10 +++++++++-
mm/mempolicy.c | 2 +-
mm/migrate.c | 4 ++--
mm/mlock.c | 2 +-
mm/mprotect.c | 2 +-
10 files changed, 27 insertions(+), 16 deletions(-)

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 2d04e3470d4c..2dd8c8a66924 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -1792,7 +1792,7 @@ static struct page *can_gather_numa_stats(pte_t pte, struct vm_area_struct *vma,
return NULL;

page = vm_normal_page(vma, addr, pte);
- if (!page)
+ if (!page || is_zone_device_page(page))
return NULL;

if (PageReserved(page))
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 834f288b3769..c47e95b02244 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2910,7 +2910,7 @@ static int split_huge_pages_pid(int pid, unsigned long vaddr_start,

if (IS_ERR(page))
continue;
- if (!page)
+ if (!page || is_zone_device_page(page))
continue;

if (!is_transparent_hugepage(page))
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 16be62d493cd..671ac7800e53 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -618,7 +618,7 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma,
goto out;
}
page = vm_normal_page(vma, address, pteval);
- if (unlikely(!page)) {
+ if (unlikely(!page) || unlikely(is_zone_device_page(page))) {
result = SCAN_PAGE_NULL;
goto out;
}
@@ -1267,7 +1267,7 @@ static int khugepaged_scan_pmd(struct mm_struct *mm,
writable = true;

page = vm_normal_page(vma, _address, pteval);
- if (unlikely(!page)) {
+ if (unlikely(!page) || unlikely(is_zone_device_page(page))) {
result = SCAN_PAGE_NULL;
goto out_unmap;
}
@@ -1479,7 +1479,8 @@ void collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr)
goto abort;

page = vm_normal_page(vma, addr, *pte);
-
+ if (WARN_ON_ONCE(page && is_zone_device_page(page)))
+ page = NULL;
/*
* Note that uprobe, debugger, or MAP_PRIVATE may change the
* page table, but the new page will not be a subpage of hpage.
@@ -1497,6 +1498,8 @@ void collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr)
if (pte_none(*pte))
continue;
page = vm_normal_page(vma, addr, *pte);
+ if (WARN_ON_ONCE(page && is_zone_device_page(page)))
+ goto abort;
page_remove_rmap(page, vma, false);
}

diff --git a/mm/ksm.c b/mm/ksm.c
index 54f78c9eecae..831b18a7a50b 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -475,7 +475,7 @@ static int break_ksm(struct vm_area_struct *vma, unsigned long addr)
cond_resched();
page = follow_page(vma, addr,
FOLL_GET | FOLL_MIGRATION | FOLL_REMOTE);
- if (IS_ERR_OR_NULL(page))
+ if (IS_ERR_OR_NULL(page) || is_zone_device_page(page))
break;
if (PageKsm(page))
ret = handle_mm_fault(vma, addr,
@@ -560,7 +560,7 @@ static struct page *get_mergeable_page(struct rmap_item *rmap_item)
goto out;

page = follow_page(vma, addr, FOLL_GET);
- if (IS_ERR_OR_NULL(page))
+ if (IS_ERR_OR_NULL(page) || is_zone_device_page(page))
goto out;
if (PageAnon(page)) {
flush_anon_page(vma, page, addr);
@@ -2308,7 +2308,7 @@ static struct rmap_item *scan_get_next_rmap_item(struct page **page)
if (ksm_test_exit(mm))
break;
*page = follow_page(vma, ksm_scan.address, FOLL_GET);
- if (IS_ERR_OR_NULL(*page)) {
+ if (IS_ERR_OR_NULL(*page) || is_zone_device_page(*page)) {
ksm_scan.address += PAGE_SIZE;
cond_resched();
continue;
diff --git a/mm/madvise.c b/mm/madvise.c
index 0316bbc6441b..e252635fe935 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -421,7 +421,7 @@ static int madvise_cold_or_pageout_pte_range(pmd_t *pmd,
continue;

page = vm_normal_page(vma, addr, ptent);
- if (!page)
+ if (!page || is_zone_device_page(page))
continue;

/*
@@ -639,7 +639,7 @@ static int madvise_free_pte_range(pmd_t *pmd, unsigned long addr,
}

page = vm_normal_page(vma, addr, ptent);
- if (!page)
+ if (!page || is_zone_device_page(page))
continue;

/*
diff --git a/mm/memory.c b/mm/memory.c
index 4cf7d4b6c950..e939cc851a0e 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -624,6 +624,14 @@ struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
if (is_zero_pfn(pfn))
return NULL;
if (pte_devmap(pte))
+ /*
+ * NOTE: New users of ZONE_DEVICE will not set pte_devmap()
+ * and will have refcounts incremented on their struct pages
+ * when they are inserted into PTEs, thus they are safe to
+ * return here. Legacy ZONE_DEVICE pages that set pte_devmap()
+ * do not have refcounts. Example of legacy ZONE_DEVICE is
+ * MEMORY_DEVICE_FS_DAX type in pmem or virtio_fs drivers.
+ */
return NULL;

print_bad_pte(vma, addr, pte, NULL);
@@ -4693,7 +4701,7 @@ static vm_fault_t do_numa_page(struct vm_fault *vmf)
pte = pte_modify(old_pte, vma->vm_page_prot);

page = vm_normal_page(vma, vmf->address, pte);
- if (!page)
+ if (!page || is_zone_device_page(page))
goto out_map;

/* TODO: handle PTE-mapped THP */
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index d39b01fd52fe..abc26890fc95 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -523,7 +523,7 @@ static int queue_pages_pte_range(pmd_t *pmd, unsigned long addr,
if (!pte_present(*pte))
continue;
page = vm_normal_page(vma, addr, *pte);
- if (!page)
+ if (!page || is_zone_device_page(page))
continue;
/*
* vm_normal_page() filters out zero pages, but there might
diff --git a/mm/migrate.c b/mm/migrate.c
index 6c1ea61f39d8..a98a219d12ab 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1620,7 +1620,7 @@ static int add_page_for_migration(struct mm_struct *mm, unsigned long addr,
goto out;

err = -ENOENT;
- if (!page)
+ if (!page || is_zone_device_page(page))
goto out;

err = 0;
@@ -1810,7 +1810,7 @@ static void do_pages_stat_array(struct mm_struct *mm, unsigned long nr_pages,
if (IS_ERR(page))
goto set_status;

- if (page) {
+ if (page && !is_zone_device_page(page)) {
err = page_to_nid(page);
put_page(page);
} else {
diff --git a/mm/mlock.c b/mm/mlock.c
index 716caf851043..b14e929084cc 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -333,7 +333,7 @@ static int mlock_pte_range(pmd_t *pmd, unsigned long addr,
if (!pte_present(*pte))
continue;
page = vm_normal_page(vma, addr, *pte);
- if (!page)
+ if (!page || is_zone_device_page(page))
continue;
if (PageTransCompound(page))
continue;
diff --git a/mm/mprotect.c b/mm/mprotect.c
index ba5592655ee3..e034aae2a98b 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -95,7 +95,7 @@ static unsigned long change_pte_range(struct mmu_gather *tlb,
continue;

page = vm_normal_page(vma, addr, oldpte);
- if (!page || PageKsm(page))
+ if (!page || is_zone_device_page(page) || PageKsm(page))
continue;

/* Also skip shared copy-on-write pages */
--
2.32.0

2022-07-15 15:07:13

by Sierra Guiza, Alejandro (Alex)

Subject: [PATCH v9 08/14] lib: test_hmm add ioctl to get zone device type

new ioctl cmd added to query zone device type. This will be
used once the test_hmm adds zone device coherent type.

Signed-off-by: Alex Sierra <[email protected]>
Acked-by: Felix Kuehling <[email protected]>
Reviewed-by: Alistair Poppple <[email protected]>
Signed-off-by: Christoph Hellwig <[email protected]>
---
lib/test_hmm.c | 11 +++++++++--
lib/test_hmm_uapi.h | 14 ++++++++++----
2 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/lib/test_hmm.c b/lib/test_hmm.c
index cfe632047839..915ef6b5b0d4 100644
--- a/lib/test_hmm.c
+++ b/lib/test_hmm.c
@@ -87,6 +87,7 @@ struct dmirror_chunk {
struct dmirror_device {
struct cdev cdevice;
struct hmm_devmem *devmem;
+ unsigned int zone_device_type;

unsigned int devmem_capacity;
unsigned int devmem_count;
@@ -1260,14 +1261,20 @@ static void dmirror_device_remove(struct dmirror_device *mdevice)
static int __init hmm_dmirror_init(void)
{
int ret;
- int id;
+ int id = 0;
+ int ndevices = 0;

ret = alloc_chrdev_region(&dmirror_dev, 0, DMIRROR_NDEVICES,
"HMM_DMIRROR");
if (ret)
goto err_unreg;

- for (id = 0; id < DMIRROR_NDEVICES; id++) {
+ memset(dmirror_devices, 0, DMIRROR_NDEVICES * sizeof(dmirror_devices[0]));
+ dmirror_devices[ndevices++].zone_device_type =
+ HMM_DMIRROR_MEMORY_DEVICE_PRIVATE;
+ dmirror_devices[ndevices++].zone_device_type =
+ HMM_DMIRROR_MEMORY_DEVICE_PRIVATE;
+ for (id = 0; id < ndevices; id++) {
ret = dmirror_device_init(dmirror_devices + id, id);
if (ret)
goto err_chrdev;
diff --git a/lib/test_hmm_uapi.h b/lib/test_hmm_uapi.h
index f14dea5dcd06..0511af7464ee 100644
--- a/lib/test_hmm_uapi.h
+++ b/lib/test_hmm_uapi.h
@@ -31,10 +31,11 @@ struct hmm_dmirror_cmd {
/* Expose the address space of the calling process through hmm device file */
#define HMM_DMIRROR_READ _IOWR('H', 0x00, 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_EXCLUSIVE _IOWR('H', 0x04, struct hmm_dmirror_cmd)
-#define HMM_DMIRROR_CHECK_EXCLUSIVE _IOWR('H', 0x05, struct hmm_dmirror_cmd)
+#define HMM_DMIRROR_MIGRATE_TO_DEV _IOWR('H', 0x02, struct hmm_dmirror_cmd)
+#define HMM_DMIRROR_MIGRATE_TO_SYS _IOWR('H', 0x03, 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)

/*
* Values returned in hmm_dmirror_cmd.ptr for HMM_DMIRROR_SNAPSHOT.
@@ -62,4 +63,9 @@ enum {
HMM_DMIRROR_PROT_DEV_PRIVATE_REMOTE = 0x30,
};

+enum {
+ /* 0 is reserved to catch uninitialized type fields */
+ HMM_DMIRROR_MEMORY_DEVICE_PRIVATE = 1,
+};
+
#endif /* _LIB_TEST_HMM_UAPI_H */
--
2.32.0

2022-07-15 15:07:15

by Sierra Guiza, Alejandro (Alex)

Subject: [PATCH v9 11/14] tools: update hmm-test to support device coherent type

Test cases such as migrate_fault and migrate_multiple, were modified to
explicit migrate from device to sys memory without the need of page
faults, when using device coherent type.

Snapshot test case updated to read memory device type first and based
on that, get the proper returned results migrate_ping_pong test case
added to test explicit migration from device to sys memory for both
private and coherent zone types.

Helpers to migrate from device to sys memory and vicerversa
were also added.

Signed-off-by: Alex Sierra <[email protected]>
Acked-by: Felix Kuehling <[email protected]>
Reviewed-by: Alistair Popple <[email protected]>
Signed-off-by: Christoph Hellwig <[email protected]>
---
tools/testing/selftests/vm/hmm-tests.c | 121 ++++++++++++++++++++-----
1 file changed, 100 insertions(+), 21 deletions(-)

diff --git a/tools/testing/selftests/vm/hmm-tests.c b/tools/testing/selftests/vm/hmm-tests.c
index 203323967b50..4b547188ec40 100644
--- a/tools/testing/selftests/vm/hmm-tests.c
+++ b/tools/testing/selftests/vm/hmm-tests.c
@@ -46,6 +46,13 @@ struct hmm_buffer {
uint64_t faults;
};

+enum {
+ HMM_PRIVATE_DEVICE_ONE,
+ HMM_PRIVATE_DEVICE_TWO,
+ HMM_COHERENCE_DEVICE_ONE,
+ HMM_COHERENCE_DEVICE_TWO,
+};
+
#define TWOMEG (1 << 21)
#define HMM_BUFFER_SIZE (1024 << 12)
#define HMM_PATH_MAX 64
@@ -60,6 +67,21 @@ FIXTURE(hmm)
unsigned int page_shift;
};

+FIXTURE_VARIANT(hmm)
+{
+ int device_number;
+};
+
+FIXTURE_VARIANT_ADD(hmm, hmm_device_private)
+{
+ .device_number = HMM_PRIVATE_DEVICE_ONE,
+};
+
+FIXTURE_VARIANT_ADD(hmm, hmm_device_coherent)
+{
+ .device_number = HMM_COHERENCE_DEVICE_ONE,
+};
+
FIXTURE(hmm2)
{
int fd0;
@@ -68,6 +90,24 @@ FIXTURE(hmm2)
unsigned int page_shift;
};

+FIXTURE_VARIANT(hmm2)
+{
+ int device_number0;
+ int device_number1;
+};
+
+FIXTURE_VARIANT_ADD(hmm2, hmm2_device_private)
+{
+ .device_number0 = HMM_PRIVATE_DEVICE_ONE,
+ .device_number1 = HMM_PRIVATE_DEVICE_TWO,
+};
+
+FIXTURE_VARIANT_ADD(hmm2, hmm2_device_coherent)
+{
+ .device_number0 = HMM_COHERENCE_DEVICE_ONE,
+ .device_number1 = HMM_COHERENCE_DEVICE_TWO,
+};
+
static int hmm_open(int unit)
{
char pathname[HMM_PATH_MAX];
@@ -81,12 +121,19 @@ static int hmm_open(int unit)
return fd;
}

+static bool hmm_is_coherent_type(int dev_num)
+{
+ return (dev_num >= HMM_COHERENCE_DEVICE_ONE);
+}
+
FIXTURE_SETUP(hmm)
{
self->page_size = sysconf(_SC_PAGE_SIZE);
self->page_shift = ffs(self->page_size) - 1;

- self->fd = hmm_open(0);
+ self->fd = hmm_open(variant->device_number);
+ if (self->fd < 0 && hmm_is_coherent_type(variant->device_number))
+ SKIP(exit(0), "DEVICE_COHERENT not available");
ASSERT_GE(self->fd, 0);
}

@@ -95,9 +142,11 @@ FIXTURE_SETUP(hmm2)
self->page_size = sysconf(_SC_PAGE_SIZE);
self->page_shift = ffs(self->page_size) - 1;

- self->fd0 = hmm_open(0);
+ self->fd0 = hmm_open(variant->device_number0);
+ if (self->fd0 < 0 && hmm_is_coherent_type(variant->device_number0))
+ SKIP(exit(0), "DEVICE_COHERENT not available");
ASSERT_GE(self->fd0, 0);
- self->fd1 = hmm_open(1);
+ self->fd1 = hmm_open(variant->device_number1);
ASSERT_GE(self->fd1, 0);
}

@@ -211,6 +260,20 @@ static void hmm_nanosleep(unsigned int n)
nanosleep(&t, NULL);
}

+static int hmm_migrate_sys_to_dev(int fd,
+ struct hmm_buffer *buffer,
+ unsigned long npages)
+{
+ return hmm_dmirror_cmd(fd, HMM_DMIRROR_MIGRATE_TO_DEV, buffer, npages);
+}
+
+static int hmm_migrate_dev_to_sys(int fd,
+ struct hmm_buffer *buffer,
+ unsigned long npages)
+{
+ return hmm_dmirror_cmd(fd, HMM_DMIRROR_MIGRATE_TO_SYS, buffer, npages);
+}
+
/*
* Simple NULL test of device open/close.
*/
@@ -875,7 +938,7 @@ TEST_F(hmm, migrate)
ptr[i] = i;

/* Migrate memory to device. */
- ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_MIGRATE, buffer, npages);
+ ret = hmm_migrate_sys_to_dev(self->fd, buffer, npages);
ASSERT_EQ(ret, 0);
ASSERT_EQ(buffer->cpages, npages);

@@ -923,7 +986,7 @@ TEST_F(hmm, migrate_fault)
ptr[i] = i;

/* Migrate memory to device. */
- ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_MIGRATE, buffer, npages);
+ ret = hmm_migrate_sys_to_dev(self->fd, buffer, npages);
ASSERT_EQ(ret, 0);
ASSERT_EQ(buffer->cpages, npages);

@@ -936,7 +999,7 @@ TEST_F(hmm, migrate_fault)
ASSERT_EQ(ptr[i], i);

/* Migrate memory to the device again. */
- ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_MIGRATE, buffer, npages);
+ ret = hmm_migrate_sys_to_dev(self->fd, buffer, npages);
ASSERT_EQ(ret, 0);
ASSERT_EQ(buffer->cpages, npages);

@@ -976,7 +1039,7 @@ TEST_F(hmm, migrate_shared)
ASSERT_NE(buffer->ptr, MAP_FAILED);

/* Migrate memory to device. */
- ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_MIGRATE, buffer, npages);
+ ret = hmm_migrate_sys_to_dev(self->fd, buffer, npages);
ASSERT_EQ(ret, -ENOENT);

hmm_buffer_free(buffer);
@@ -1015,7 +1078,7 @@ TEST_F(hmm2, migrate_mixed)
p = buffer->ptr;

/* Migrating a protected area should be an error. */
- ret = hmm_dmirror_cmd(self->fd1, HMM_DMIRROR_MIGRATE, buffer, npages);
+ ret = hmm_migrate_sys_to_dev(self->fd1, buffer, npages);
ASSERT_EQ(ret, -EINVAL);

/* Punch a hole after the first page address. */
@@ -1023,7 +1086,7 @@ TEST_F(hmm2, migrate_mixed)
ASSERT_EQ(ret, 0);

/* We expect an error if the vma doesn't cover the range. */
- ret = hmm_dmirror_cmd(self->fd1, HMM_DMIRROR_MIGRATE, buffer, 3);
+ ret = hmm_migrate_sys_to_dev(self->fd1, buffer, 3);
ASSERT_EQ(ret, -EINVAL);

/* Page 2 will be a read-only zero page. */
@@ -1055,13 +1118,13 @@ TEST_F(hmm2, migrate_mixed)

/* Now try to migrate pages 2-5 to device 1. */
buffer->ptr = p + 2 * self->page_size;
- ret = hmm_dmirror_cmd(self->fd1, HMM_DMIRROR_MIGRATE, buffer, 4);
+ ret = hmm_migrate_sys_to_dev(self->fd1, buffer, 4);
ASSERT_EQ(ret, 0);
ASSERT_EQ(buffer->cpages, 4);

/* Page 5 won't be migrated to device 0 because it's on device 1. */
buffer->ptr = p + 5 * self->page_size;
- ret = hmm_dmirror_cmd(self->fd0, HMM_DMIRROR_MIGRATE, buffer, 1);
+ ret = hmm_migrate_sys_to_dev(self->fd0, buffer, 1);
ASSERT_EQ(ret, -ENOENT);
buffer->ptr = p;

@@ -1070,8 +1133,12 @@ TEST_F(hmm2, migrate_mixed)
}

/*
- * Migrate anonymous memory to device private memory and fault it back to system
- * memory multiple times.
+ * Migrate anonymous memory to device memory and back to system memory
+ * multiple times. In case of private zone configuration, this is done
+ * through fault pages accessed by CPU. In case of coherent zone configuration,
+ * the pages from the device should be explicitly migrated back to system memory.
+ * The reason is Coherent device zone has coherent access by CPU, therefore
+ * it will not generate any page fault.
*/
TEST_F(hmm, migrate_multiple)
{
@@ -1107,8 +1174,7 @@ TEST_F(hmm, migrate_multiple)
ptr[i] = i;

/* Migrate memory to device. */
- ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_MIGRATE, buffer,
- npages);
+ ret = hmm_migrate_sys_to_dev(self->fd, buffer, npages);
ASSERT_EQ(ret, 0);
ASSERT_EQ(buffer->cpages, npages);

@@ -1116,7 +1182,13 @@ TEST_F(hmm, migrate_multiple)
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. */
+ /* Migrate back to system memory and check them. */
+ if (hmm_is_coherent_type(variant->device_number)) {
+ ret = hmm_migrate_dev_to_sys(self->fd, buffer, npages);
+ ASSERT_EQ(ret, 0);
+ ASSERT_EQ(buffer->cpages, npages);
+ }
+
for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i)
ASSERT_EQ(ptr[i], i);

@@ -1354,13 +1426,13 @@ TEST_F(hmm2, snapshot)

/* Page 5 will be migrated to device 0. */
buffer->ptr = p + 5 * self->page_size;
- ret = hmm_dmirror_cmd(self->fd0, HMM_DMIRROR_MIGRATE, buffer, 1);
+ ret = hmm_migrate_sys_to_dev(self->fd0, buffer, 1);
ASSERT_EQ(ret, 0);
ASSERT_EQ(buffer->cpages, 1);

/* Page 6 will be migrated to device 1. */
buffer->ptr = p + 6 * self->page_size;
- ret = hmm_dmirror_cmd(self->fd1, HMM_DMIRROR_MIGRATE, buffer, 1);
+ ret = hmm_migrate_sys_to_dev(self->fd1, buffer, 1);
ASSERT_EQ(ret, 0);
ASSERT_EQ(buffer->cpages, 1);

@@ -1377,9 +1449,16 @@ TEST_F(hmm2, snapshot)
ASSERT_EQ(m[2], HMM_DMIRROR_PROT_ZERO | HMM_DMIRROR_PROT_READ);
ASSERT_EQ(m[3], HMM_DMIRROR_PROT_READ);
ASSERT_EQ(m[4], HMM_DMIRROR_PROT_WRITE);
- ASSERT_EQ(m[5], HMM_DMIRROR_PROT_DEV_PRIVATE_LOCAL |
- HMM_DMIRROR_PROT_WRITE);
- ASSERT_EQ(m[6], HMM_DMIRROR_PROT_NONE);
+ if (!hmm_is_coherent_type(variant->device_number0)) {
+ ASSERT_EQ(m[5], HMM_DMIRROR_PROT_DEV_PRIVATE_LOCAL |
+ HMM_DMIRROR_PROT_WRITE);
+ ASSERT_EQ(m[6], HMM_DMIRROR_PROT_NONE);
+ } else {
+ ASSERT_EQ(m[5], HMM_DMIRROR_PROT_DEV_COHERENT_LOCAL |
+ HMM_DMIRROR_PROT_WRITE);
+ ASSERT_EQ(m[6], HMM_DMIRROR_PROT_DEV_COHERENT_REMOTE |
+ HMM_DMIRROR_PROT_WRITE);
+ }

hmm_buffer_free(buffer);
}
--
2.32.0

2022-07-15 15:07:16

by Sierra Guiza, Alejandro (Alex)

Subject: [PATCH v9 10/14] lib: add support for device coherent type in test_hmm

Device Coherent type uses device memory that is coherently accesible by
the CPU. This could be shown as SP (special purpose) memory range
at the BIOS-e820 memory enumeration. If no SP memory is supported in
system, this could be faked by setting CONFIG_EFI_FAKE_MEMMAP.

Currently, test_hmm only supports two different SP ranges of at least
256MB size. This could be specified in the kernel parameter variable
efi_fake_mem. Ex. Two SP ranges of 1GB starting at 0x100000000 &
0x140000000 physical address. Ex.
efi_fake_mem=1G@0x100000000:0x40000,1G@0x140000000:0x40000

Private and coherent device mirror instances can be created in the same
probed. This is done by passing the module parameters spm_addr_dev0 &
spm_addr_dev1. In this case, it will create four instances of
device_mirror. The first two correspond to private device type, the
last two to coherent type. Then, they can be easily accessed from user
space through /dev/hmm_mirror<num_device>. Usually num_device 0 and 1
are for private, and 2 and 3 for coherent types. If no module
parameters are passed, two instances of private type device_mirror will
be created only.

Signed-off-by: Alex Sierra <[email protected]>
Acked-by: Felix Kuehling <[email protected]>
Reviewed-by: Alistair Poppple <[email protected]>
---
lib/test_hmm.c | 253 +++++++++++++++++++++++++++++++++-----------
lib/test_hmm_uapi.h | 4 +
2 files changed, 196 insertions(+), 61 deletions(-)

diff --git a/lib/test_hmm.c b/lib/test_hmm.c
index afb30af9f3ff..7930853e7fc5 100644
--- a/lib/test_hmm.c
+++ b/lib/test_hmm.c
@@ -32,11 +32,22 @@

#include "test_hmm_uapi.h"

-#define DMIRROR_NDEVICES 2
+#define DMIRROR_NDEVICES 4
#define DMIRROR_RANGE_FAULT_TIMEOUT 1000
#define DEVMEM_CHUNK_SIZE (256 * 1024 * 1024U)
#define DEVMEM_CHUNKS_RESERVE 16

+/*
+ * For device_private pages, dpage is just a dummy struct page
+ * representing a piece of device memory. dmirror_devmem_alloc_page
+ * allocates a real system memory page as backing storage to fake a
+ * real device. zone_device_data points to that backing page. But
+ * for device_coherent memory, the struct page represents real
+ * physical CPU-accessible memory that we can use directly.
+ */
+#define BACKING_PAGE(page) (is_device_private_page((page)) ? \
+ (page)->zone_device_data : (page))
+
static unsigned long spm_addr_dev0;
module_param(spm_addr_dev0, long, 0644);
MODULE_PARM_DESC(spm_addr_dev0,
@@ -125,6 +136,21 @@ static int dmirror_bounce_init(struct dmirror_bounce *bounce,
return 0;
}

+static bool dmirror_is_private_zone(struct dmirror_device *mdevice)
+{
+ return (mdevice->zone_device_type ==
+ HMM_DMIRROR_MEMORY_DEVICE_PRIVATE) ? true : false;
+}
+
+static enum migrate_vma_direction
+dmirror_select_device(struct dmirror *dmirror)
+{
+ return (dmirror->mdevice->zone_device_type ==
+ HMM_DMIRROR_MEMORY_DEVICE_PRIVATE) ?
+ MIGRATE_VMA_SELECT_DEVICE_PRIVATE :
+ MIGRATE_VMA_SELECT_DEVICE_COHERENT;
+}
+
static void dmirror_bounce_fini(struct dmirror_bounce *bounce)
{
vfree(bounce->ptr);
@@ -575,16 +601,19 @@ static int dmirror_allocate_chunk(struct dmirror_device *mdevice,
static struct page *dmirror_devmem_alloc_page(struct dmirror_device *mdevice)
{
struct page *dpage = NULL;
- struct page *rpage;
+ struct page *rpage = NULL;

/*
- * This is a fake device so we alloc real system memory to store
- * our device memory.
+ * For ZONE_DEVICE private type, this is a fake device so we allocate
+ * real system memory to store our device memory.
+ * For ZONE_DEVICE coherent type we use the actual dpage to store the
+ * data and ignore rpage.
*/
- rpage = alloc_page(GFP_HIGHUSER);
- if (!rpage)
- return NULL;
-
+ if (dmirror_is_private_zone(mdevice)) {
+ rpage = alloc_page(GFP_HIGHUSER);
+ if (!rpage)
+ return NULL;
+ }
spin_lock(&mdevice->lock);

if (mdevice->free_pages) {
@@ -603,7 +632,8 @@ static struct page *dmirror_devmem_alloc_page(struct dmirror_device *mdevice)
return dpage;

error:
- __free_page(rpage);
+ if (rpage)
+ __free_page(rpage);
return NULL;
}

@@ -629,12 +659,16 @@ static void dmirror_migrate_alloc_and_copy(struct migrate_vma *args,
* unallocated pte_none() or read-only zero page.
*/
spage = migrate_pfn_to_page(*src);
+ if (WARN(spage && is_zone_device_page(spage),
+ "page already in device spage pfn: 0x%lx\n",
+ page_to_pfn(spage)))
+ continue;

dpage = dmirror_devmem_alloc_page(mdevice);
if (!dpage)
continue;

- rpage = dpage->zone_device_data;
+ rpage = BACKING_PAGE(dpage);
if (spage)
copy_highpage(rpage, spage);
else
@@ -648,6 +682,8 @@ static void dmirror_migrate_alloc_and_copy(struct migrate_vma *args,
*/
rpage->zone_device_data = dmirror;

+ pr_debug("migrating from sys to dev pfn src: 0x%lx pfn dst: 0x%lx\n",
+ page_to_pfn(spage), page_to_pfn(dpage));
*dst = migrate_pfn(page_to_pfn(dpage));
if ((*src & MIGRATE_PFN_WRITE) ||
(!spage && args->vma->vm_flags & VM_WRITE))
@@ -725,11 +761,7 @@ static int dmirror_migrate_finalize_and_map(struct migrate_vma *args,
if (!dpage)
continue;

- /*
- * 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;
+ entry = BACKING_PAGE(dpage);
if (*dst & MIGRATE_PFN_WRITE)
entry = xa_tag_pointer(entry, DPT_XA_TAG_WRITE);
entry = xa_store(&dmirror->pt, pfn, entry, GFP_ATOMIC);
@@ -809,15 +841,126 @@ static int dmirror_exclusive(struct dmirror *dmirror,
return ret;
}

-static int dmirror_migrate(struct dmirror *dmirror,
- struct hmm_dmirror_cmd *cmd)
+static vm_fault_t dmirror_devmem_fault_alloc_and_copy(struct migrate_vma *args,
+ struct dmirror *dmirror)
+{
+ const unsigned long *src = args->src;
+ unsigned long *dst = args->dst;
+ unsigned long start = args->start;
+ unsigned long end = args->end;
+ unsigned long addr;
+
+ for (addr = start; addr < end; addr += PAGE_SIZE,
+ src++, dst++) {
+ struct page *dpage, *spage;
+
+ spage = migrate_pfn_to_page(*src);
+ if (!spage || !(*src & 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_vma(GFP_HIGHUSER_MOVABLE, args->vma, addr);
+ if (!dpage)
+ continue;
+ pr_debug("migrating from dev to sys pfn src: 0x%lx pfn dst: 0x%lx\n",
+ page_to_pfn(spage), page_to_pfn(dpage));
+
+ lock_page(dpage);
+ xa_erase(&dmirror->pt, addr >> PAGE_SHIFT);
+ copy_highpage(dpage, spage);
+ *dst = migrate_pfn(page_to_pfn(dpage));
+ if (*src & MIGRATE_PFN_WRITE)
+ *dst |= MIGRATE_PFN_WRITE;
+ }
+ return 0;
+}
+
+static unsigned long
+dmirror_successful_migrated_pages(struct migrate_vma *migrate)
+{
+ unsigned long cpages = 0;
+ unsigned long i;
+
+ for (i = 0; i < migrate->npages; i++) {
+ if (migrate->src[i] & MIGRATE_PFN_VALID &&
+ migrate->src[i] & MIGRATE_PFN_MIGRATE)
+ cpages++;
+ }
+ return cpages;
+}
+
+static int dmirror_migrate_to_system(struct dmirror *dmirror,
+ struct hmm_dmirror_cmd *cmd)
{
unsigned long start, end, addr;
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[64] = { 0 };
+ unsigned long dst_pfns[64] = { 0 };
+ struct migrate_vma args;
+ unsigned long next;
+ int ret;
+
+ start = cmd->addr;
+ end = start + size;
+ if (end < start)
+ return -EINVAL;
+
+ /* Since the mm is for the mirrored process, get a reference first. */
+ if (!mmget_not_zero(mm))
+ return -EINVAL;
+
+ cmd->cpages = 0;
+ mmap_read_lock(mm);
+ for (addr = start; addr < end; addr = next) {
+ vma = vma_lookup(mm, addr);
+ if (!vma || !(vma->vm_flags & VM_READ)) {
+ ret = -EINVAL;
+ goto out;
+ }
+ next = min(end, addr + (ARRAY_SIZE(src_pfns) << PAGE_SHIFT));
+ if (next > vma->vm_end)
+ next = vma->vm_end;
+
+ args.vma = vma;
+ args.src = src_pfns;
+ args.dst = dst_pfns;
+ args.start = addr;
+ args.end = next;
+ args.pgmap_owner = dmirror->mdevice;
+ args.flags = dmirror_select_device(dmirror);
+
+ ret = migrate_vma_setup(&args);
+ if (ret)
+ goto out;
+
+ pr_debug("Migrating from device mem to sys mem\n");
+ dmirror_devmem_fault_alloc_and_copy(&args, dmirror);
+
+ migrate_vma_pages(&args);
+ cmd->cpages += dmirror_successful_migrated_pages(&args);
+ migrate_vma_finalize(&args);
+ }
+out:
+ mmap_read_unlock(mm);
+ mmput(mm);
+
+ return ret;
+}
+
+static int dmirror_migrate_to_device(struct dmirror *dmirror,
+ struct hmm_dmirror_cmd *cmd)
+{
+ unsigned long start, end, addr;
+ unsigned long size = cmd->npages << PAGE_SHIFT;
+ struct mm_struct *mm = dmirror->notifier.mm;
+ struct vm_area_struct *vma;
+ unsigned long src_pfns[64] = { 0 };
+ unsigned long dst_pfns[64] = { 0 };
struct dmirror_bounce bounce;
struct migrate_vma args;
unsigned long next;
@@ -854,6 +997,7 @@ static int dmirror_migrate(struct dmirror *dmirror,
if (ret)
goto out;

+ pr_debug("Migrating from sys mem to device mem\n");
dmirror_migrate_alloc_and_copy(&args, dmirror);
migrate_vma_pages(&args);
dmirror_migrate_finalize_and_map(&args, dmirror);
@@ -862,7 +1006,10 @@ static int dmirror_migrate(struct dmirror *dmirror,
mmap_read_unlock(mm);
mmput(mm);

- /* Return the migrated data for verification. */
+ /*
+ * Return the migrated data for verification.
+ * Only for pages in device zone
+ */
ret = dmirror_bounce_init(&bounce, start, size);
if (ret)
return ret;
@@ -905,6 +1052,12 @@ static void dmirror_mkentry(struct dmirror *dmirror, struct hmm_range *range,
*perm = HMM_DMIRROR_PROT_DEV_PRIVATE_LOCAL;
else
*perm = HMM_DMIRROR_PROT_DEV_PRIVATE_REMOTE;
+ } else if (is_device_coherent_page(page)) {
+ /* Is the page migrated to this device or some other? */
+ if (dmirror->mdevice == dmirror_page_to_device(page))
+ *perm = HMM_DMIRROR_PROT_DEV_COHERENT_LOCAL;
+ else
+ *perm = HMM_DMIRROR_PROT_DEV_COHERENT_REMOTE;
} else if (is_zero_pfn(page_to_pfn(page)))
*perm = HMM_DMIRROR_PROT_ZERO;
else
@@ -1092,8 +1245,12 @@ static long dmirror_fops_unlocked_ioctl(struct file *filp,
ret = dmirror_write(dmirror, &cmd);
break;

- case HMM_DMIRROR_MIGRATE:
- ret = dmirror_migrate(dmirror, &cmd);
+ case HMM_DMIRROR_MIGRATE_TO_DEV:
+ ret = dmirror_migrate_to_device(dmirror, &cmd);
+ break;
+
+ case HMM_DMIRROR_MIGRATE_TO_SYS:
+ ret = dmirror_migrate_to_system(dmirror, &cmd);
break;

case HMM_DMIRROR_EXCLUSIVE:
@@ -1155,14 +1312,13 @@ static const struct file_operations dmirror_fops = {

static void dmirror_devmem_free(struct page *page)
{
- struct page *rpage = page->zone_device_data;
+ struct page *rpage = BACKING_PAGE(page);
struct dmirror_device *mdevice;

- if (rpage)
+ if (rpage != page)
__free_page(rpage);

mdevice = dmirror_page_to_device(page);
-
spin_lock(&mdevice->lock);
mdevice->cfree++;
page->zone_device_data = mdevice->free_pages;
@@ -1170,43 +1326,11 @@ static void dmirror_devmem_free(struct page *page)
spin_unlock(&mdevice->lock);
}

-static vm_fault_t dmirror_devmem_fault_alloc_and_copy(struct migrate_vma *args,
- struct dmirror *dmirror)
-{
- const unsigned long *src = args->src;
- unsigned long *dst = args->dst;
- unsigned long start = args->start;
- unsigned long end = args->end;
- unsigned long addr;
-
- for (addr = start; addr < end; addr += PAGE_SIZE,
- src++, dst++) {
- struct page *dpage, *spage;
-
- spage = migrate_pfn_to_page(*src);
- if (!spage || !(*src & MIGRATE_PFN_MIGRATE))
- continue;
- spage = spage->zone_device_data;
-
- dpage = alloc_page_vma(GFP_HIGHUSER_MOVABLE, args->vma, addr);
- if (!dpage)
- continue;
-
- lock_page(dpage);
- xa_erase(&dmirror->pt, addr >> PAGE_SHIFT);
- copy_highpage(dpage, spage);
- *dst = migrate_pfn(page_to_pfn(dpage));
- if (*src & MIGRATE_PFN_WRITE)
- *dst |= MIGRATE_PFN_WRITE;
- }
- return 0;
-}
-
static vm_fault_t dmirror_devmem_fault(struct vm_fault *vmf)
{
struct migrate_vma args;
- unsigned long src_pfns;
- unsigned long dst_pfns;
+ unsigned long src_pfns = 0;
+ unsigned long dst_pfns = 0;
struct page *rpage;
struct dmirror *dmirror;
vm_fault_t ret;
@@ -1226,7 +1350,7 @@ static vm_fault_t dmirror_devmem_fault(struct vm_fault *vmf)
args.src = &src_pfns;
args.dst = &dst_pfns;
args.pgmap_owner = dmirror->mdevice;
- args.flags = MIGRATE_VMA_SELECT_DEVICE_PRIVATE;
+ args.flags = dmirror_select_device(dmirror);

if (migrate_vma_setup(&args))
return VM_FAULT_SIGBUS;
@@ -1305,6 +1429,12 @@ static int __init hmm_dmirror_init(void)
HMM_DMIRROR_MEMORY_DEVICE_PRIVATE;
dmirror_devices[ndevices++].zone_device_type =
HMM_DMIRROR_MEMORY_DEVICE_PRIVATE;
+ if (spm_addr_dev0 && spm_addr_dev1) {
+ dmirror_devices[ndevices++].zone_device_type =
+ HMM_DMIRROR_MEMORY_DEVICE_COHERENT;
+ dmirror_devices[ndevices++].zone_device_type =
+ HMM_DMIRROR_MEMORY_DEVICE_COHERENT;
+ }
for (id = 0; id < ndevices; id++) {
ret = dmirror_device_init(dmirror_devices + id, id);
if (ret)
@@ -1327,7 +1457,8 @@ static void __exit hmm_dmirror_exit(void)
int id;

for (id = 0; id < DMIRROR_NDEVICES; id++)
- dmirror_device_remove(dmirror_devices + id);
+ if (dmirror_devices[id].zone_device_type)
+ dmirror_device_remove(dmirror_devices + id);
unregister_chrdev_region(dmirror_dev, DMIRROR_NDEVICES);
}

diff --git a/lib/test_hmm_uapi.h b/lib/test_hmm_uapi.h
index f700da7807c1..e31d58c9034a 100644
--- a/lib/test_hmm_uapi.h
+++ b/lib/test_hmm_uapi.h
@@ -50,6 +50,8 @@ struct hmm_dmirror_cmd {
* device the ioctl() is made
* HMM_DMIRROR_PROT_DEV_PRIVATE_REMOTE: Migrated device private page on some
* other device
+ * HMM_DMIRROR_PROT_DEV_COHERENT: Migrate device coherent page on the device
+ * the ioctl() is made
*/
enum {
HMM_DMIRROR_PROT_ERROR = 0xFF,
@@ -61,6 +63,8 @@ enum {
HMM_DMIRROR_PROT_ZERO = 0x10,
HMM_DMIRROR_PROT_DEV_PRIVATE_LOCAL = 0x20,
HMM_DMIRROR_PROT_DEV_PRIVATE_REMOTE = 0x30,
+ HMM_DMIRROR_PROT_DEV_COHERENT_LOCAL = 0x40,
+ HMM_DMIRROR_PROT_DEV_COHERENT_REMOTE = 0x50,
};

enum {
--
2.32.0

2022-07-15 15:07:23

by Sierra Guiza, Alejandro (Alex)

Subject: [PATCH v9 14/14] tools: add selftests to hmm for COW in device memory

The objective is to test device migration mechanism in pages marked
as COW, for private and coherent device type. In case of writing to
COW private page(s), a page fault will migrate pages back to system
memory first. Then, these pages will be duplicated. In case of COW
device coherent type, pages are duplicated directly from device
memory.

Signed-off-by: Alex Sierra <[email protected]>
Acked-by: Felix Kuehling <[email protected]>
---
tools/testing/selftests/vm/hmm-tests.c | 80 ++++++++++++++++++++++++++
1 file changed, 80 insertions(+)

diff --git a/tools/testing/selftests/vm/hmm-tests.c b/tools/testing/selftests/vm/hmm-tests.c
index bb38b9777610..716b62c05e3d 100644
--- a/tools/testing/selftests/vm/hmm-tests.c
+++ b/tools/testing/selftests/vm/hmm-tests.c
@@ -1874,4 +1874,84 @@ TEST_F(hmm, hmm_gup_test)
close(gup_fd);
hmm_buffer_free(buffer);
}
+
+/*
+ * Test copy-on-write in device pages.
+ * In case of writing to COW private page(s), a page fault will migrate pages
+ * back to system memory first. Then, these pages will be duplicated. In case
+ * of COW device coherent type, pages are duplicated directly from device
+ * memory.
+ */
+TEST_F(hmm, hmm_cow_in_device)
+{
+ struct hmm_buffer *buffer;
+ unsigned long npages;
+ unsigned long size;
+ unsigned long i;
+ int *ptr;
+ int ret;
+ unsigned char *m;
+ pid_t pid;
+ int status;
+
+ npages = 4;
+ 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);
+
+ pid = fork();
+ if (pid == -1)
+ ASSERT_EQ(pid, 0);
+ if (!pid) {
+ /* Child process waitd for SIGTERM from the parent. */
+ while (1) {
+ }
+ perror("Should not reach this\n");
+ exit(0);
+ }
+ /* Parent process writes to COW pages(s) and gets a
+ * new copy in system. In case of device private pages,
+ * this write causes a migration to system mem first.
+ */
+ for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i)
+ ptr[i] = i;
+
+ /* Terminate child and wait */
+ EXPECT_EQ(0, kill(pid, SIGTERM));
+ EXPECT_EQ(pid, waitpid(pid, &status, 0));
+ EXPECT_NE(0, WIFSIGNALED(status));
+ EXPECT_EQ(SIGTERM, WTERMSIG(status));
+
+ /* Take snapshot to CPU pagetables */
+ ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_SNAPSHOT, buffer, npages);
+ ASSERT_EQ(ret, 0);
+ ASSERT_EQ(buffer->cpages, npages);
+ m = buffer->mirror;
+ for (i = 0; i < npages; i++)
+ ASSERT_EQ(HMM_DMIRROR_PROT_WRITE, m[i]);
+
+ hmm_buffer_free(buffer);
+}
TEST_HARNESS_MAIN
--
2.32.0

2022-07-15 15:07:36

by Sierra Guiza, Alejandro (Alex)

Subject: [PATCH v9 12/14] tools: update test_hmm script to support SP config

Add two more parameters to set spm_addr_dev0 & spm_addr_dev1
addresses. These two parameters configure the start SP
addresses for each device in test_hmm driver.
Consequently, this configures zone device type as coherent.

Signed-off-by: Alex Sierra <[email protected]>
Acked-by: Felix Kuehling <[email protected]>
Reviewed-by: Alistair Popple <[email protected]>
Signed-off-by: Christoph Hellwig <[email protected]>
---
tools/testing/selftests/vm/test_hmm.sh | 24 +++++++++++++++++++++---
1 file changed, 21 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/vm/test_hmm.sh b/tools/testing/selftests/vm/test_hmm.sh
index 0647b525a625..539c9371e592 100755
--- a/tools/testing/selftests/vm/test_hmm.sh
+++ b/tools/testing/selftests/vm/test_hmm.sh
@@ -40,11 +40,26 @@ check_test_requirements()

load_driver()
{
- modprobe $DRIVER > /dev/null 2>&1
+ if [ $# -eq 0 ]; then
+ modprobe $DRIVER > /dev/null 2>&1
+ else
+ if [ $# -eq 2 ]; then
+ modprobe $DRIVER spm_addr_dev0=$1 spm_addr_dev1=$2
+ > /dev/null 2>&1
+ else
+ echo "Missing module parameters. Make sure pass"\
+ "spm_addr_dev0 and spm_addr_dev1"
+ usage
+ fi
+ fi
if [ $? == 0 ]; then
major=$(awk "\$2==\"HMM_DMIRROR\" {print \$1}" /proc/devices)
mknod /dev/hmm_dmirror0 c $major 0
mknod /dev/hmm_dmirror1 c $major 1
+ if [ $# -eq 2 ]; then
+ mknod /dev/hmm_dmirror2 c $major 2
+ mknod /dev/hmm_dmirror3 c $major 3
+ fi
fi
}

@@ -58,7 +73,7 @@ run_smoke()
{
echo "Running smoke test. Note, this test provides basic coverage."

- load_driver
+ load_driver $1 $2
$(dirname "${BASH_SOURCE[0]}")/hmm-tests
unload_driver
}
@@ -75,6 +90,9 @@ usage()
echo "# Smoke testing"
echo "./${TEST_NAME}.sh smoke"
echo
+ echo "# Smoke testing with SPM enabled"
+ echo "./${TEST_NAME}.sh smoke <spm_addr_dev0> <spm_addr_dev1>"
+ echo
exit 0
}

@@ -84,7 +102,7 @@ function run_test()
usage
else
if [ "$1" = "smoke" ]; then
- run_smoke
+ run_smoke $2 $3
else
usage
fi
--
2.32.0

2022-07-15 15:07:57

by Sierra Guiza, Alejandro (Alex)

Subject: [PATCH v9 07/14] drm/amdkfd: add SPM support for SVM

When CPU is connected throug XGMI, it has coherent
access to VRAM resource. In this case that resource
is taken from a table in the device gmc aperture base.
This resource is used along with the device type, which could
be DEVICE_PRIVATE or DEVICE_COHERENT to create the device
page map region.
Also, MIGRATE_VMA_SELECT_DEVICE_COHERENT flag is selected for
coherent type case during migration to device.

Signed-off-by: Alex Sierra <[email protected]>
Reviewed-by: Felix Kuehling <[email protected]>
Signed-off-by: Christoph Hellwig <[email protected]>
---
drivers/gpu/drm/amd/amdkfd/kfd_migrate.c | 34 +++++++++++++++---------
1 file changed, 21 insertions(+), 13 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
index e44376c2ecdc..f73e3e340413 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
@@ -671,13 +671,15 @@ svm_migrate_vma_to_ram(struct amdgpu_device *adev, struct svm_range *prange,
migrate.vma = vma;
migrate.start = start;
migrate.end = end;
- migrate.flags = MIGRATE_VMA_SELECT_DEVICE_PRIVATE;
migrate.pgmap_owner = SVM_ADEV_PGMAP_OWNER(adev);
+ if (adev->gmc.xgmi.connected_to_cpu)
+ migrate.flags = MIGRATE_VMA_SELECT_DEVICE_COHERENT;
+ else
+ migrate.flags = MIGRATE_VMA_SELECT_DEVICE_PRIVATE;

buf = kvcalloc(npages,
2 * sizeof(*migrate.src) + sizeof(uint64_t) + sizeof(dma_addr_t),
GFP_KERNEL);
-
if (!buf)
goto out;

@@ -947,7 +949,7 @@ int svm_migrate_init(struct amdgpu_device *adev)
{
struct kfd_dev *kfddev = adev->kfd.dev;
struct dev_pagemap *pgmap;
- struct resource *res;
+ struct resource *res = NULL;
unsigned long size;
void *r;

@@ -962,28 +964,34 @@ int svm_migrate_init(struct amdgpu_device *adev)
* should remove reserved size
*/
size = ALIGN(adev->gmc.real_vram_size, 2ULL << 20);
- res = devm_request_free_mem_region(adev->dev, &iomem_resource, size);
- if (IS_ERR(res))
- return -ENOMEM;
+ if (adev->gmc.xgmi.connected_to_cpu) {
+ pgmap->range.start = adev->gmc.aper_base;
+ pgmap->range.end = adev->gmc.aper_base + adev->gmc.aper_size - 1;
+ pgmap->type = MEMORY_DEVICE_COHERENT;
+ } else {
+ res = devm_request_free_mem_region(adev->dev, &iomem_resource, size);
+ if (IS_ERR(res))
+ return -ENOMEM;
+ pgmap->range.start = res->start;
+ pgmap->range.end = res->end;
+ pgmap->type = MEMORY_DEVICE_PRIVATE;
+ }

- pgmap->type = MEMORY_DEVICE_PRIVATE;
pgmap->nr_range = 1;
- pgmap->range.start = res->start;
- pgmap->range.end = res->end;
pgmap->ops = &svm_migrate_pgmap_ops;
pgmap->owner = SVM_ADEV_PGMAP_OWNER(adev);
- pgmap->flags = MIGRATE_VMA_SELECT_DEVICE_PRIVATE;
-
+ pgmap->flags = 0;
/* Device manager releases device-specific resources, memory region and
* pgmap when driver disconnects from device.
*/
r = devm_memremap_pages(adev->dev, pgmap);
if (IS_ERR(r)) {
pr_err("failed to register HMM device memory\n");
-
/* Disable SVM support capability */
pgmap->type = 0;
- devm_release_mem_region(adev->dev, res->start, resource_size(res));
+ if (pgmap->type == MEMORY_DEVICE_PRIVATE)
+ devm_release_mem_region(adev->dev, res->start,
+ res->end - res->start + 1);
return PTR_ERR(r);
}

--
2.32.0

2022-07-15 15:08:16

by Sierra Guiza, Alejandro (Alex)

Subject: [PATCH v9 09/14] lib: test_hmm add module param for zone device type

In order to configure device coherent in test_hmm, two module parameters
should be passed, which correspond to the SP start address of each
device (2) spm_addr_dev0 & spm_addr_dev1. If no parameters are passed,
private device type is configured.

Signed-off-by: Alex Sierra <[email protected]>
Acked-by: Felix Kuehling <[email protected]>
Reviewed-by: Alistair Poppple <[email protected]>
Signed-off-by: Christoph Hellwig <[email protected]>
---
lib/test_hmm.c | 73 ++++++++++++++++++++++++++++++++-------------
lib/test_hmm_uapi.h | 1 +
2 files changed, 53 insertions(+), 21 deletions(-)

diff --git a/lib/test_hmm.c b/lib/test_hmm.c
index 915ef6b5b0d4..afb30af9f3ff 100644
--- a/lib/test_hmm.c
+++ b/lib/test_hmm.c
@@ -37,6 +37,16 @@
#define DEVMEM_CHUNK_SIZE (256 * 1024 * 1024U)
#define DEVMEM_CHUNKS_RESERVE 16

+static unsigned long spm_addr_dev0;
+module_param(spm_addr_dev0, long, 0644);
+MODULE_PARM_DESC(spm_addr_dev0,
+ "Specify start address for SPM (special purpose memory) used for device 0. By setting this Coherent device type will be used. Make sure spm_addr_dev1 is set too. Minimum SPM size should be DEVMEM_CHUNK_SIZE.");
+
+static unsigned long spm_addr_dev1;
+module_param(spm_addr_dev1, long, 0644);
+MODULE_PARM_DESC(spm_addr_dev1,
+ "Specify start address for SPM (special purpose memory) used for device 1. By setting this Coherent device type will be used. Make sure spm_addr_dev0 is set too. Minimum SPM size should be DEVMEM_CHUNK_SIZE.");
+
static const struct dev_pagemap_ops dmirror_devmem_ops;
static const struct mmu_interval_notifier_ops dmirror_min_ops;
static dev_t dmirror_dev;
@@ -455,28 +465,44 @@ static int dmirror_write(struct dmirror *dmirror, struct hmm_dmirror_cmd *cmd)
return ret;
}

-static bool dmirror_allocate_chunk(struct dmirror_device *mdevice,
+static int dmirror_allocate_chunk(struct dmirror_device *mdevice,
struct page **ppage)
{
struct dmirror_chunk *devmem;
- struct resource *res;
+ struct resource *res = NULL;
unsigned long pfn;
unsigned long pfn_first;
unsigned long pfn_last;
void *ptr;
+ int ret = -ENOMEM;

devmem = kzalloc(sizeof(*devmem), GFP_KERNEL);
if (!devmem)
- return false;
+ return ret;

- res = request_free_mem_region(&iomem_resource, DEVMEM_CHUNK_SIZE,
- "hmm_dmirror");
- if (IS_ERR(res))
+ switch (mdevice->zone_device_type) {
+ case HMM_DMIRROR_MEMORY_DEVICE_PRIVATE:
+ res = request_free_mem_region(&iomem_resource, DEVMEM_CHUNK_SIZE,
+ "hmm_dmirror");
+ if (IS_ERR_OR_NULL(res))
+ goto err_devmem;
+ devmem->pagemap.range.start = res->start;
+ devmem->pagemap.range.end = res->end;
+ devmem->pagemap.type = MEMORY_DEVICE_PRIVATE;
+ break;
+ case HMM_DMIRROR_MEMORY_DEVICE_COHERENT:
+ devmem->pagemap.range.start = (MINOR(mdevice->cdevice.dev) - 2) ?
+ spm_addr_dev0 :
+ spm_addr_dev1;
+ devmem->pagemap.range.end = devmem->pagemap.range.start +
+ DEVMEM_CHUNK_SIZE - 1;
+ devmem->pagemap.type = MEMORY_DEVICE_COHERENT;
+ break;
+ default:
+ ret = -EINVAL;
goto err_devmem;
+ }

- devmem->pagemap.type = MEMORY_DEVICE_PRIVATE;
- devmem->pagemap.range.start = res->start;
- devmem->pagemap.range.end = res->end;
devmem->pagemap.nr_range = 1;
devmem->pagemap.ops = &dmirror_devmem_ops;
devmem->pagemap.owner = mdevice;
@@ -497,10 +523,14 @@ static bool dmirror_allocate_chunk(struct dmirror_device *mdevice,
mdevice->devmem_capacity = new_capacity;
mdevice->devmem_chunks = new_chunks;
}
-
ptr = memremap_pages(&devmem->pagemap, numa_node_id());
- if (IS_ERR(ptr))
+ if (IS_ERR_OR_NULL(ptr)) {
+ if (ptr)
+ ret = PTR_ERR(ptr);
+ else
+ ret = -EFAULT;
goto err_release;
+ }

devmem->mdevice = mdevice;
pfn_first = devmem->pagemap.range.start >> PAGE_SHIFT;
@@ -529,15 +559,17 @@ static bool dmirror_allocate_chunk(struct dmirror_device *mdevice,
}
spin_unlock(&mdevice->lock);

- return true;
+ return 0;

err_release:
mutex_unlock(&mdevice->devmem_lock);
- release_mem_region(devmem->pagemap.range.start, range_len(&devmem->pagemap.range));
+ if (res && devmem->pagemap.type == MEMORY_DEVICE_PRIVATE)
+ release_mem_region(devmem->pagemap.range.start,
+ range_len(&devmem->pagemap.range));
err_devmem:
kfree(devmem);

- return false;
+ return ret;
}

static struct page *dmirror_devmem_alloc_page(struct dmirror_device *mdevice)
@@ -562,7 +594,7 @@ static struct page *dmirror_devmem_alloc_page(struct dmirror_device *mdevice)
spin_unlock(&mdevice->lock);
} else {
spin_unlock(&mdevice->lock);
- if (!dmirror_allocate_chunk(mdevice, &dpage))
+ if (dmirror_allocate_chunk(mdevice, &dpage))
goto error;
}

@@ -1232,10 +1264,8 @@ static int dmirror_device_init(struct dmirror_device *mdevice, int id)
if (ret)
return ret;

- /* Build a list of free ZONE_DEVICE private struct pages */
- dmirror_allocate_chunk(mdevice, NULL);
-
- return 0;
+ /* Build a list of free ZONE_DEVICE struct pages */
+ return dmirror_allocate_chunk(mdevice, NULL);
}

static void dmirror_device_remove(struct dmirror_device *mdevice)
@@ -1248,8 +1278,9 @@ static void dmirror_device_remove(struct dmirror_device *mdevice)
mdevice->devmem_chunks[i];

memunmap_pages(&devmem->pagemap);
- release_mem_region(devmem->pagemap.range.start,
- range_len(&devmem->pagemap.range));
+ 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);
diff --git a/lib/test_hmm_uapi.h b/lib/test_hmm_uapi.h
index 0511af7464ee..f700da7807c1 100644
--- a/lib/test_hmm_uapi.h
+++ b/lib/test_hmm_uapi.h
@@ -66,6 +66,7 @@ enum {
enum {
/* 0 is reserved to catch uninitialized type fields */
HMM_DMIRROR_MEMORY_DEVICE_PRIVATE = 1,
+ HMM_DMIRROR_MEMORY_DEVICE_COHERENT,
};

#endif /* _LIB_TEST_HMM_UAPI_H */
--
2.32.0

2022-07-15 15:10:18

by Sierra Guiza, Alejandro (Alex)

Subject: [PATCH v9 13/14] tools: add hmm gup tests for device coherent type

The intention is to test hmm device coherent type under different get
user pages paths. Also, test gup with FOLL_LONGTERM flag set in
device coherent pages. These pages should get migrated back to system
memory.

Signed-off-by: Alex Sierra <[email protected]>
Reviewed-by: Alistair Popple <[email protected]>
---
tools/testing/selftests/vm/hmm-tests.c | 110 +++++++++++++++++++++++++
1 file changed, 110 insertions(+)

diff --git a/tools/testing/selftests/vm/hmm-tests.c b/tools/testing/selftests/vm/hmm-tests.c
index 4b547188ec40..bb38b9777610 100644
--- a/tools/testing/selftests/vm/hmm-tests.c
+++ b/tools/testing/selftests/vm/hmm-tests.c
@@ -36,6 +36,7 @@
* in the usual include/uapi/... directory.
*/
#include "../../../../lib/test_hmm_uapi.h"
+#include "../../../../mm/gup_test.h"

struct hmm_buffer {
void *ptr;
@@ -59,6 +60,9 @@ enum {
#define NTIMES 10

#define ALIGN(x, a) (((x) + (a - 1)) & (~((a) - 1)))
+/* Just the flags we need, copied from mm.h: */
+#define FOLL_WRITE 0x01 /* check pte is writable */
+#define FOLL_LONGTERM 0x10000 /* mapping lifetime is indefinite */

FIXTURE(hmm)
{
@@ -1764,4 +1768,110 @@ TEST_F(hmm, exclusive_cow)
hmm_buffer_free(buffer);
}

+static int gup_test_exec(int gup_fd, unsigned long addr, int cmd,
+ int npages, int size, int flags)
+{
+ struct gup_test gup = {
+ .nr_pages_per_call = npages,
+ .addr = addr,
+ .gup_flags = FOLL_WRITE | flags,
+ .size = size,
+ };
+
+ if (ioctl(gup_fd, cmd, &gup)) {
+ perror("ioctl on error\n");
+ return errno;
+ }
+
+ return 0;
+}
+
+/*
+ * Test get user device pages through gup_test. Setting PIN_LONGTERM flag.
+ * This should trigger a migration back to system memory for both, private
+ * and coherent type pages.
+ * This test makes use of gup_test module. Make sure GUP_TEST_CONFIG is added
+ * to your configuration before you run it.
+ */
+TEST_F(hmm, hmm_gup_test)
+{
+ struct hmm_buffer *buffer;
+ int gup_fd;
+ unsigned long npages;
+ unsigned long size;
+ unsigned long i;
+ int *ptr;
+ int ret;
+ unsigned char *m;
+
+ gup_fd = open("/sys/kernel/debug/gup_test", O_RDWR);
+ if (gup_fd == -1)
+ SKIP(return, "Skipping test, could not find gup_test driver");
+
+ npages = 4;
+ 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);
+
+ ASSERT_EQ(gup_test_exec(gup_fd,
+ (unsigned long)buffer->ptr,
+ GUP_BASIC_TEST, 1, self->page_size, 0), 0);
+ ASSERT_EQ(gup_test_exec(gup_fd,
+ (unsigned long)buffer->ptr + 1 * self->page_size,
+ GUP_FAST_BENCHMARK, 1, self->page_size, 0), 0);
+ ASSERT_EQ(gup_test_exec(gup_fd,
+ (unsigned long)buffer->ptr + 2 * self->page_size,
+ PIN_FAST_BENCHMARK, 1, self->page_size, FOLL_LONGTERM), 0);
+ ASSERT_EQ(gup_test_exec(gup_fd,
+ (unsigned long)buffer->ptr + 3 * self->page_size,
+ PIN_LONGTERM_BENCHMARK, 1, self->page_size, 0), 0);
+
+ /* Take snapshot to CPU pagetables */
+ ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_SNAPSHOT, buffer, npages);
+ ASSERT_EQ(ret, 0);
+ ASSERT_EQ(buffer->cpages, npages);
+ m = buffer->mirror;
+ if (hmm_is_coherent_type(variant->device_number)) {
+ ASSERT_EQ(HMM_DMIRROR_PROT_DEV_COHERENT_LOCAL | HMM_DMIRROR_PROT_WRITE, m[0]);
+ ASSERT_EQ(HMM_DMIRROR_PROT_DEV_COHERENT_LOCAL | HMM_DMIRROR_PROT_WRITE, m[1]);
+ } else {
+ ASSERT_EQ(HMM_DMIRROR_PROT_WRITE, m[0]);
+ ASSERT_EQ(HMM_DMIRROR_PROT_WRITE, m[1]);
+ }
+ ASSERT_EQ(HMM_DMIRROR_PROT_WRITE, m[2]);
+ ASSERT_EQ(HMM_DMIRROR_PROT_WRITE, m[3]);
+ /*
+ * Check again the content on the pages. Make sure there's no
+ * corrupted data.
+ */
+ for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i)
+ ASSERT_EQ(ptr[i], i);
+
+ close(gup_fd);
+ hmm_buffer_free(buffer);
+}
TEST_HARNESS_MAIN
--
2.32.0

2022-07-18 10:53:58

by David Hildenbrand

Subject: Re: [PATCH v9 02/14] mm: move page zone helpers from mm.h to mmzone.h

On 15.07.22 17:05, Alex Sierra wrote:
> [WHY]
> It makes more sense to have these helpers in zone specific header
> file, rather than the generic mm.h
>
> Signed-off-by: Alex Sierra <[email protected]>

Acked-by: David Hildenbrand <[email protected]>


--
Thanks,

David / dhildenb

2022-07-18 10:54:11

by David Hildenbrand

Subject: Re: [PATCH v9 04/14] mm: handling Non-LRU pages returned by vm_normal_pages

On 15.07.22 17:05, Alex Sierra wrote:
> With DEVICE_COHERENT, we'll soon have vm_normal_pages() return
> device-managed anonymous pages that are not LRU pages. Although they
> behave like normal pages for purposes of mapping in CPU page, and for
> COW. They do not support LRU lists, NUMA migration or THP.
>
> Callers to follow_page() currently don't expect ZONE_DEVICE pages,
> however, with DEVICE_COHERENT we might now return ZONE_DEVICE. Check
> for ZONE_DEVICE pages in applicable users of follow_page() as well.
>
> Signed-off-by: Alex Sierra <[email protected]>
> Acked-by: Felix Kuehling <[email protected]> (v2)
> Reviewed-by: Alistair Popple <[email protected]> (v6)
>

Acked-by: David Hildenbrand <[email protected]>

--
Thanks,

David / dhildenb

2022-07-18 10:59:02

by David Hildenbrand

Subject: Re: [PATCH v9 06/14] mm/gup: migrate device coherent pages when pinning instead of failing

On 15.07.22 17:05, Alex Sierra wrote:
> From: Alistair Popple <[email protected]>
>
> Currently any attempts to pin a device coherent page will fail. This is
> because device coherent pages need to be managed by a device driver, and
> pinning them would prevent a driver from migrating them off the device.
>
> However this is no reason to fail pinning of these pages. These are
> coherent and accessible from the CPU so can be migrated just like
> pinning ZONE_MOVABLE pages. So instead of failing all attempts to pin
> them first try migrating them out of ZONE_DEVICE.
>
> [hch: rebased to the split device memory checks,
> moved migrate_device_page to migrate_device.c]
>
> Signed-off-by: Alistair Popple <[email protected]>
> Acked-by: Felix Kuehling <[email protected]>
> Signed-off-by: Christoph Hellwig <[email protected]>

[...]

> /*
> * Try to move out any movable page before pinning the range.
> */
> @@ -1919,7 +1948,8 @@ static long check_and_migrate_movable_pages(unsigned long nr_pages,
> folio_nr_pages(folio));
> }
>
> - if (!list_empty(&movable_page_list) || isolation_error_count)
> + if (!list_empty(&movable_page_list) || isolation_error_count
> + || coherent_pages)

The common style is to

a) add the || to the end of the previous line
b) indent such the we have a nice-to-read alignment

if (!list_empty(&movable_page_list) || isolation_error_count ||
coherent_pages)


Apart from that lgtm.

Reviewed-by: David Hildenbrand <[email protected]>

--
Thanks,

David / dhildenb

2022-07-18 17:59:07

by Felix Kuehling

Subject: Re: [PATCH v9 02/14] mm: move page zone helpers from mm.h to mmzone.h

On 2022-07-18 06:50, David Hildenbrand wrote:
> On 15.07.22 17:05, Alex Sierra wrote:
>> [WHY]
>> It makes more sense to have these helpers in zone specific header
>> file, rather than the generic mm.h
>>
>> Signed-off-by: Alex Sierra <[email protected]>
> Acked-by: David Hildenbrand <[email protected]>

Thank you! I don't think I have the authority to give this a
Reviewed-by. Who does?

Regards,
  Felix

2022-07-18 18:58:30

by David Hildenbrand

Subject: Re: [PATCH v9 02/14] mm: move page zone helpers from mm.h to mmzone.h

On 18.07.22 19:52, Felix Kuehling wrote:
> On 2022-07-18 06:50, David Hildenbrand wrote:
>> On 15.07.22 17:05, Alex Sierra wrote:
>>> [WHY]
>>> It makes more sense to have these helpers in zone specific header
>>> file, rather than the generic mm.h
>>>
>>> Signed-off-by: Alex Sierra <[email protected]>
>> Acked-by: David Hildenbrand <[email protected]>
>
> Thank you! I don't think I have the authority to give this a
> Reviewed-by. Who does?


Sure you can. Everybody can give Reviewed-by/Tested-by ... tags. :)


--
Thanks,

David / dhildenb

2022-07-18 20:33:56

by Andrew Morton

Subject: Re: [PATCH v9 06/14] mm/gup: migrate device coherent pages when pinning instead of failing

On Mon, 18 Jul 2022 12:56:29 +0200 David Hildenbrand <[email protected]> wrote:

> > /*
> > * Try to move out any movable page before pinning the range.
> > */
> > @@ -1919,7 +1948,8 @@ static long check_and_migrate_movable_pages(unsigned long nr_pages,
> > folio_nr_pages(folio));
> > }
> >
> > - if (!list_empty(&movable_page_list) || isolation_error_count)
> > + if (!list_empty(&movable_page_list) || isolation_error_count
> > + || coherent_pages)
>
> The common style is to
>
> a) add the || to the end of the previous line
> b) indent such the we have a nice-to-read alignment
>
> if (!list_empty(&movable_page_list) || isolation_error_count ||
> coherent_pages)
>

I missed that. This series is now in mm-stable so any fix will need to
be a standalone followup patch, please.

> Apart from that lgtm.
>
> Reviewed-by: David Hildenbrand <[email protected]>

And your reviewed-by's will be lost. Stupid git.

2022-07-19 08:45:36

by David Hildenbrand

Subject: Re: [PATCH v9 06/14] mm/gup: migrate device coherent pages when pinning instead of failing

On 18.07.22 22:32, Andrew Morton wrote:
> On Mon, 18 Jul 2022 12:56:29 +0200 David Hildenbrand <[email protected]> wrote:
>
>>> /*
>>> * Try to move out any movable page before pinning the range.
>>> */
>>> @@ -1919,7 +1948,8 @@ static long check_and_migrate_movable_pages(unsigned long nr_pages,
>>> folio_nr_pages(folio));
>>> }
>>>
>>> - if (!list_empty(&movable_page_list) || isolation_error_count)
>>> + if (!list_empty(&movable_page_list) || isolation_error_count
>>> + || coherent_pages)
>>
>> The common style is to
>>
>> a) add the || to the end of the previous line
>> b) indent such the we have a nice-to-read alignment
>>
>> if (!list_empty(&movable_page_list) || isolation_error_count ||
>> coherent_pages)
>>
>
> I missed that. This series is now in mm-stable so any fix will need to
> be a standalone followup patch, please.
>
>> Apart from that lgtm.
>>
>> Reviewed-by: David Hildenbrand <[email protected]>
>
> And your reviewed-by's will be lost. Stupid git.

I know, I already raised my concerns regarding the new workflow, so I
won't repeat that. I can understand (too some degree) that we don't want
code to change just before the new merge window opens.

But I do wonder if we really don't even want to do subject+description
updates. Sure, the commit IDs will change. Who cares?

Anyhow, it is what it is.

--
Thanks,

David / dhildenb

2022-07-26 02:36:51

by Sierra Guiza, Alejandro (Alex)

Subject: Re: [PATCH v9 06/14] mm/gup: migrate device coherent pages when pinning instead of failing

On 7/18/2022 3:32 PM, Andrew Morton wrote:
> On Mon, 18 Jul 2022 12:56:29 +0200 David Hildenbrand <[email protected]> wrote:
>
>>> /*
>>> * Try to move out any movable page before pinning the range.
>>> */
>>> @@ -1919,7 +1948,8 @@ static long check_and_migrate_movable_pages(unsigned long nr_pages,
>>> folio_nr_pages(folio));
>>> }
>>>
>>> - if (!list_empty(&movable_page_list) || isolation_error_count)
>>> + if (!list_empty(&movable_page_list) || isolation_error_count
>>> + || coherent_pages)
>> The common style is to
>>
>> a) add the || to the end of the previous line
>> b) indent such the we have a nice-to-read alignment
>>
>> if (!list_empty(&movable_page_list) || isolation_error_count ||
>> coherent_pages)
>>
> I missed that. This series is now in mm-stable so any fix will need to
> be a standalone followup patch, please.
Hi Andrew,
Just wanted to make sure nothing is missing from our side to merge this
patch series.

Regards,
Alex Sierra
>
>> Apart from that lgtm.
>>
>> Reviewed-by: David Hildenbrand <[email protected]>
> And your reviewed-by's will be lost. Stupid git.

2022-07-26 19:18:46

by Andrew Morton

Subject: Re: [PATCH v9 06/14] mm/gup: migrate device coherent pages when pinning instead of failing

On Mon, 25 Jul 2022 21:22:06 -0500 "Sierra Guiza, Alejandro (Alex)" <[email protected]> wrote:

> >> a) add the || to the end of the previous line
> >> b) indent such the we have a nice-to-read alignment
> >>
> >> if (!list_empty(&movable_page_list) || isolation_error_count ||
> >> coherent_pages)
> >>
> > I missed that. This series is now in mm-stable so any fix will need to
> > be a standalone followup patch, please.
> Hi Andrew,
> Just wanted to make sure nothing is missing from our side to merge this
> patch series.

It's queued in mm-stable and all looks good for a 5.20-rc1 merge.

2023-06-15 19:41:40

by Peter Xu

Subject: Re: [PATCH v9 02/14] mm: move page zone helpers from mm.h to mmzone.h

Hello, all,

On Fri, Jul 15, 2022 at 10:05:09AM -0500, Alex Sierra wrote:
> +static inline enum zone_type page_zonenum(const struct page *page)
> +{
> + ASSERT_EXCLUSIVE_BITS(page->flags, ZONES_MASK << ZONES_PGSHIFT);
> + return (page->flags >> ZONES_PGSHIFT) & ZONES_MASK;
> +}

Sorry to hijack this patch - not directly relevant to the movement, but
relevant to this helper, so maybe I can leverage the cc list..

My question is whether page_zonenum() is ready for taking all kinds of tail
pages?

Zone device tail pages all look fine, per memmap_init_zone_device(). The
question was other kinds of usual compound pages, like either thp or
hugetlb. IIUC page->flags can be uninitialized for those tail pages.

Asking because I noticed it seems possible that page_zonenum() can just
take any random tail page as input, e.g.:

try_grab_folio -> is_pci_p2pdma_page -> is_zone_device_page -> page_zonenum

I'm worried it'll just read fake things, but maybe I just missed something?

Thanks,

--
Peter Xu

2023-06-15 20:21:03

by Matthew Wilcox

Subject: Re: [PATCH v9 02/14] mm: move page zone helpers from mm.h to mmzone.h

On Thu, Jun 15, 2023 at 03:33:12PM -0400, Peter Xu wrote:
> My question is whether page_zonenum() is ready for taking all kinds of tail
> pages?
>
> Zone device tail pages all look fine, per memmap_init_zone_device(). The
> question was other kinds of usual compound pages, like either thp or
> hugetlb. IIUC page->flags can be uninitialized for those tail pages.

I don't think that's true. It's my understanding that page->flags is
initialised for all pages in memmap at boot / hotplug / delayed-init
time. So you can check things like zone, node, etc on literally any
page. Contrariwise, those flags are not available in tail pages for
use by the entity that has allocated a compound page / large folio.

Also, I don't believe zone device pages support compound allocation.
I think they're always allocated as order-0.

2023-06-15 20:59:08

by Peter Xu

Subject: Re: [PATCH v9 02/14] mm: move page zone helpers from mm.h to mmzone.h

On Thu, Jun 15, 2023 at 09:15:26PM +0100, Matthew Wilcox wrote:
> On Thu, Jun 15, 2023 at 03:33:12PM -0400, Peter Xu wrote:
> > My question is whether page_zonenum() is ready for taking all kinds of tail
> > pages?
> >
> > Zone device tail pages all look fine, per memmap_init_zone_device(). The
> > question was other kinds of usual compound pages, like either thp or
> > hugetlb. IIUC page->flags can be uninitialized for those tail pages.
>
> I don't think that's true. It's my understanding that page->flags is
> initialised for all pages in memmap at boot / hotplug / delayed-init
> time. So you can check things like zone, node, etc on literally any
> page. Contrariwise, those flags are not available in tail pages for
> use by the entity that has allocated a compound page / large folio.

Oh so the zone mask is special. Fair enough.

>
> Also, I don't believe zone device pages support compound allocation.
> I think they're always allocated as order-0.

Totally not familiar with zone device pages, but memmap_init_zone_device()
has pfns_per_compound which can be >1. From there, memmap_init_compound()
does go ahead and setup pages as compound ones.

Thanks!

--
Peter Xu