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authorJérôme Glisse <jglisse@redhat.com>2017-09-08 16:12:24 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-09-08 18:26:46 -0700
commitdf6ad69838fc9dcdbee0dcf2fc2c6f1113f8d609 (patch)
treed5774eba9a9c2204123b8ca36d9cba90bfa9ad64 /mm
parent8315ada7f095bfa2cae0cd1e915b95bf6226897d (diff)
downloadlinux-df6ad69838fc9dcdbee0dcf2fc2c6f1113f8d609.tar.bz2
mm/device-public-memory: device memory cache coherent with CPU
Platform with advance system bus (like CAPI or CCIX) allow device memory to be accessible from CPU in a cache coherent fashion. Add a new type of ZONE_DEVICE to represent such memory. The use case are the same as for the un-addressable device memory but without all the corners cases. Link: http://lkml.kernel.org/r/20170817000548.32038-19-jglisse@redhat.com Signed-off-by: Jérôme Glisse <jglisse@redhat.com> Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Balbir Singh <bsingharora@gmail.com> Cc: David Nellans <dnellans@nvidia.com> Cc: Evgeny Baskakov <ebaskakov@nvidia.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Mark Hairgrove <mhairgrove@nvidia.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Sherry Cheung <SCheung@nvidia.com> Cc: Subhash Gutti <sgutti@nvidia.com> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Bob Liu <liubo95@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/Kconfig11
-rw-r--r--mm/gup.c7
-rw-r--r--mm/hmm.c4
-rw-r--r--mm/madvise.c2
-rw-r--r--mm/memcontrol.c12
-rw-r--r--mm/memory.c46
-rw-r--r--mm/migrate.c57
-rw-r--r--mm/swap.c11
8 files changed, 118 insertions, 32 deletions
diff --git a/mm/Kconfig b/mm/Kconfig
index ec27855db133..7bea16697d87 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -720,12 +720,23 @@ config HMM_MIRROR
config DEVICE_PRIVATE
bool "Unaddressable device memory (GPU memory, ...)"
depends on ARCH_HAS_HMM
+ select HMM
help
Allows creation of struct pages to represent unaddressable device
memory; i.e., memory that is only accessible from the device (or
group of devices). You likely also want to select HMM_MIRROR.
+config DEVICE_PUBLIC
+ bool "Addressable device memory (like GPU memory)"
+ depends on ARCH_HAS_HMM
+ select HMM
+
+ help
+ Allows creation of struct pages to represent addressable device
+ memory; i.e., memory that is accessible from both the device and
+ the CPU
+
config FRAME_VECTOR
bool
diff --git a/mm/gup.c b/mm/gup.c
index 76fd199aaae2..b2b4d4263768 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -456,6 +456,13 @@ static int get_gate_page(struct mm_struct *mm, unsigned long address,
if ((gup_flags & FOLL_DUMP) || !is_zero_pfn(pte_pfn(*pte)))
goto unmap;
*page = pte_page(*pte);
+
+ /*
+ * This should never happen (a device public page in the gate
+ * area).
+ */
+ if (is_device_public_page(*page))
+ goto unmap;
}
get_page(*page);
out:
diff --git a/mm/hmm.c b/mm/hmm.c
index c9d23ef80552..b31d56662202 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -737,7 +737,7 @@ EXPORT_SYMBOL(hmm_vma_fault);
#endif /* IS_ENABLED(CONFIG_HMM_MIRROR) */
-#if IS_ENABLED(CONFIG_DEVICE_PRIVATE)
+#if IS_ENABLED(CONFIG_DEVICE_PRIVATE) || IS_ENABLED(CONFIG_DEVICE_PUBLIC)
struct page *hmm_vma_alloc_locked_page(struct vm_area_struct *vma,
unsigned long addr)
{
@@ -1177,4 +1177,4 @@ static int __init hmm_init(void)
}
device_initcall(hmm_init);
-#endif /* IS_ENABLED(CONFIG_DEVICE_PRIVATE) */
+#endif /* CONFIG_DEVICE_PRIVATE || CONFIG_DEVICE_PUBLIC */
diff --git a/mm/madvise.c b/mm/madvise.c
index eea1c733286f..21261ff0466f 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -355,7 +355,7 @@ static int madvise_free_pte_range(pmd_t *pmd, unsigned long addr,
continue;
}
- page = vm_normal_page(vma, addr, ptent);
+ page = _vm_normal_page(vma, addr, ptent, true);
if (!page)
continue;
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 8aa98f9bc723..126a939b600a 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4623,10 +4623,11 @@ out:
* 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). 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.
+ * 3(MC_TARGET_DEVICE): like MC_TARGET_PAGE but page is MEMORY_DEVICE_PUBLIC
+ * or MEMORY_DEVICE_PRIVATE (so ZONE_DEVICE page 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.
*
* See Documentations/vm/hmm.txt and include/linux/hmm.h
*
@@ -4657,7 +4658,8 @@ static enum mc_target_type get_mctgt_type(struct vm_area_struct *vma,
*/
if (page->mem_cgroup == mc.from) {
ret = MC_TARGET_PAGE;
- if (is_device_private_page(page))
+ if (is_device_private_page(page) ||
+ is_device_public_page(page))
ret = MC_TARGET_DEVICE;
if (target)
target->page = page;
diff --git a/mm/memory.c b/mm/memory.c
index 079eeac0b009..ad0ea1af1f44 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -818,8 +818,8 @@ static void print_bad_pte(struct vm_area_struct *vma, unsigned long addr,
#else
# define HAVE_PTE_SPECIAL 0
#endif
-struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
- pte_t pte)
+struct page *_vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
+ pte_t pte, bool with_public_device)
{
unsigned long pfn = pte_pfn(pte);
@@ -830,8 +830,31 @@ struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
return vma->vm_ops->find_special_page(vma, addr);
if (vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP))
return NULL;
- if (!is_zero_pfn(pfn))
- print_bad_pte(vma, addr, pte, NULL);
+ if (is_zero_pfn(pfn))
+ return NULL;
+
+ /*
+ * Device public pages are special pages (they are ZONE_DEVICE
+ * pages but different from persistent memory). They behave
+ * allmost like normal pages. The difference is that they are
+ * not on the lru and thus should never be involve with any-
+ * thing that involve lru manipulation (mlock, numa balancing,
+ * ...).
+ *
+ * This is why we still want to return NULL for such page from
+ * vm_normal_page() so that we do not have to special case all
+ * call site of vm_normal_page().
+ */
+ if (likely(pfn < highest_memmap_pfn)) {
+ struct page *page = pfn_to_page(pfn);
+
+ if (is_device_public_page(page)) {
+ if (with_public_device)
+ return page;
+ return NULL;
+ }
+ }
+ print_bad_pte(vma, addr, pte, NULL);
return NULL;
}
@@ -1012,6 +1035,19 @@ copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
get_page(page);
page_dup_rmap(page, false);
rss[mm_counter(page)]++;
+ } else if (pte_devmap(pte)) {
+ page = pte_page(pte);
+
+ /*
+ * Cache coherent device memory behave like regular page and
+ * not like persistent memory page. For more informations see
+ * MEMORY_DEVICE_CACHE_COHERENT in memory_hotplug.h
+ */
+ if (is_device_public_page(page)) {
+ get_page(page);
+ page_dup_rmap(page, false);
+ rss[mm_counter(page)]++;
+ }
}
out_set_pte:
@@ -1267,7 +1303,7 @@ again:
if (pte_present(ptent)) {
struct page *page;
- page = vm_normal_page(vma, addr, ptent);
+ page = _vm_normal_page(vma, addr, ptent, true);
if (unlikely(details) && page) {
/*
* unmap_shared_mapping_pages() wants to
diff --git a/mm/migrate.c b/mm/migrate.c
index e581253ef330..618aeb5e9cde 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -36,6 +36,7 @@
#include <linux/hugetlb.h>
#include <linux/hugetlb_cgroup.h>
#include <linux/gfp.h>
+#include <linux/pfn_t.h>
#include <linux/memremap.h>
#include <linux/userfaultfd_k.h>
#include <linux/balloon_compaction.h>
@@ -239,10 +240,14 @@ static bool remove_migration_pte(struct page *page, struct vm_area_struct *vma,
if (is_write_migration_entry(entry))
pte = maybe_mkwrite(pte, vma);
- if (unlikely(is_zone_device_page(new)) &&
- is_device_private_page(new)) {
- entry = make_device_private_entry(new, pte_write(pte));
- pte = swp_entry_to_pte(entry);
+ if (unlikely(is_zone_device_page(new))) {
+ if (is_device_private_page(new)) {
+ entry = make_device_private_entry(new, pte_write(pte));
+ pte = swp_entry_to_pte(entry);
+ } else if (is_device_public_page(new)) {
+ pte = pte_mkdevmap(pte);
+ flush_dcache_page(new);
+ }
} else
flush_dcache_page(new);
@@ -437,12 +442,11 @@ int migrate_page_move_mapping(struct address_space *mapping,
void **pslot;
/*
- * ZONE_DEVICE pages have 1 refcount always held by their device
- *
- * Note that DAX memory will never reach that point as it does not have
- * the MEMORY_DEVICE_ALLOW_MIGRATE flag set (see memory_hotplug.h).
+ * Device public or private pages have an extra refcount as they are
+ * ZONE_DEVICE pages.
*/
- expected_count += is_zone_device_page(page);
+ expected_count += is_device_private_page(page);
+ expected_count += is_device_public_page(page);
if (!mapping) {
/* Anonymous page without mapping */
@@ -2123,7 +2127,6 @@ out_unlock:
#endif /* CONFIG_NUMA */
-
struct migrate_vma {
struct vm_area_struct *vma;
unsigned long *dst;
@@ -2263,7 +2266,7 @@ again:
pfn = 0;
goto next;
}
- page = vm_normal_page(migrate->vma, addr, pte);
+ page = _vm_normal_page(migrate->vma, addr, pte, true);
mpfn = migrate_pfn(pfn) | MIGRATE_PFN_MIGRATE;
mpfn |= pte_write(pte) ? MIGRATE_PFN_WRITE : 0;
}
@@ -2406,10 +2409,19 @@ static bool migrate_vma_check_page(struct page *page)
if (is_device_private_page(page))
return true;
- /* Other ZONE_DEVICE memory type are not supported */
- return false;
+ /*
+ * Only allow device public page to be migrated and account for
+ * the extra reference count imply by ZONE_DEVICE pages.
+ */
+ if (!is_device_public_page(page))
+ return false;
+ extra++;
}
+ /* For file back page */
+ if (page_mapping(page))
+ extra += 1 + page_has_private(page);
+
if ((page_count(page) - extra) > page_mapcount(page))
return false;
@@ -2647,11 +2659,18 @@ static void migrate_vma_insert_page(struct migrate_vma *migrate,
*/
__SetPageUptodate(page);
- if (is_zone_device_page(page) && is_device_private_page(page)) {
- swp_entry_t swp_entry;
-
- swp_entry = make_device_private_entry(page, vma->vm_flags & VM_WRITE);
- entry = swp_entry_to_pte(swp_entry);
+ if (is_zone_device_page(page)) {
+ if (is_device_private_page(page)) {
+ swp_entry_t swp_entry;
+
+ swp_entry = make_device_private_entry(page, vma->vm_flags & VM_WRITE);
+ entry = swp_entry_to_pte(swp_entry);
+ } else if (is_device_public_page(page)) {
+ entry = pte_mkold(mk_pte(page, READ_ONCE(vma->vm_page_prot)));
+ if (vma->vm_flags & VM_WRITE)
+ entry = pte_mkwrite(pte_mkdirty(entry));
+ entry = pte_mkdevmap(entry);
+ }
} else {
entry = mk_pte(page, vma->vm_page_prot);
if (vma->vm_flags & VM_WRITE)
@@ -2768,7 +2787,7 @@ static void migrate_vma_pages(struct migrate_vma *migrate)
migrate->src[i] &= ~MIGRATE_PFN_MIGRATE;
continue;
}
- } else {
+ } else if (!is_device_public_page(newpage)) {
/*
* Other types of ZONE_DEVICE page are not
* supported.
diff --git a/mm/swap.c b/mm/swap.c
index 62d96b8e5eb3..9295ae960d66 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -765,6 +765,17 @@ void release_pages(struct page **pages, int nr, bool cold)
if (is_huge_zero_page(page))
continue;
+ /* Device public page can not be huge page */
+ if (is_device_public_page(page)) {
+ if (locked_pgdat) {
+ spin_unlock_irqrestore(&locked_pgdat->lru_lock,
+ flags);
+ locked_pgdat = NULL;
+ }
+ put_zone_device_private_or_public_page(page);
+ continue;
+ }
+
page = compound_head(page);
if (!put_page_testzero(page))
continue;