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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>
This commit is contained in:
Jérôme Glisse 2017-09-08 16:12:24 -07:00 committed by Linus Torvalds
parent 8315ada7f0
commit df6ad69838
14 changed files with 158 additions and 46 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
fs/proc/task_mmu.c
View File

@ -1267,7 +1267,7 @@ static pagemap_entry_t pte_to_pagemap_entry(struct pagemapread *pm,
if (pm->show_pfn)
frame = pte_pfn(pte);
flags |= PM_PRESENT;
page = vm_normal_page(vma, addr, pte);
page = _vm_normal_page(vma, addr, pte, true);
if (pte_soft_dirty(pte))
flags |= PM_SOFT_DIRTY;
} else if (is_swap_pte(pte)) {

4
include/linux/hmm.h
View File

@ -327,7 +327,7 @@ int hmm_vma_fault(struct vm_area_struct *vma,
#endif /* IS_ENABLED(CONFIG_HMM_MIRROR) */
#if IS_ENABLED(CONFIG_DEVICE_PRIVATE)
#if IS_ENABLED(CONFIG_DEVICE_PRIVATE) || IS_ENABLED(CONFIG_DEVICE_PUBLIC)
struct hmm_devmem;
struct page *hmm_vma_alloc_locked_page(struct vm_area_struct *vma,
@ -494,7 +494,7 @@ struct hmm_device {
*/
struct hmm_device *hmm_device_new(void *drvdata);
void hmm_device_put(struct hmm_device *hmm_device);
#endif /* IS_ENABLED(CONFIG_DEVICE_PRIVATE) */
#endif /* CONFIG_DEVICE_PRIVATE || CONFIG_DEVICE_PUBLIC */
/* Below are for HMM internal use only! Not to be used by device driver! */

1
include/linux/ioport.h
View File

@ -131,6 +131,7 @@ enum {
IORES_DESC_PERSISTENT_MEMORY = 4,
IORES_DESC_PERSISTENT_MEMORY_LEGACY = 5,
IORES_DESC_DEVICE_PRIVATE_MEMORY = 6,
IORES_DESC_DEVICE_PUBLIC_MEMORY = 7,
};
/* helpers to define resources */

21
include/linux/memremap.h
View File

@ -57,10 +57,18 @@ static inline struct vmem_altmap *to_vmem_altmap(unsigned long memmap_start)
*
* A more complete discussion of unaddressable memory may be found in
* include/linux/hmm.h and Documentation/vm/hmm.txt.
*
* MEMORY_DEVICE_PUBLIC:
* Device memory that is cache coherent from device and CPU point of view. This
* is use on platform that have an advance system bus (like CAPI or CCIX). 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 allow to pin such memory so that it can always be evicted.
*/
enum memory_type {
MEMORY_DEVICE_HOST = 0,
MEMORY_DEVICE_PRIVATE,
MEMORY_DEVICE_PUBLIC,
};
/*
@ -92,6 +100,8 @@ enum memory_type {
* The page_free() callback is called once the page refcount reaches 1
* (ZONE_DEVICE pages never reach 0 refcount unless there is a refcount bug.
* This allows the device driver to implement its own memory management.)
*
* For MEMORY_DEVICE_PUBLIC only the page_free() callback matter.
*/
typedef int (*dev_page_fault_t)(struct vm_area_struct *vma,
unsigned long addr,
@ -134,6 +144,12 @@ static inline bool is_device_private_page(const struct page *page)
return is_zone_device_page(page) &&
page->pgmap->type == MEMORY_DEVICE_PRIVATE;
}
static inline bool is_device_public_page(const struct page *page)
{
return is_zone_device_page(page) &&
page->pgmap->type == MEMORY_DEVICE_PUBLIC;
}
#else
static inline void *devm_memremap_pages(struct device *dev,
struct resource *res, struct percpu_ref *ref,
@ -157,6 +173,11 @@ static inline bool is_device_private_page(const struct page *page)
{
return false;
}
static inline bool is_device_public_page(const struct page *page)
{
return false;
}
#endif
/**

20
include/linux/mm.h
View File

@ -800,15 +800,16 @@ static inline bool is_zone_device_page(const struct page *page)
}
#endif
#ifdef CONFIG_DEVICE_PRIVATE
void put_zone_device_private_page(struct page *page);
#if IS_ENABLED(CONFIG_DEVICE_PRIVATE) || IS_ENABLED(CONFIG_DEVICE_PUBLIC)
void put_zone_device_private_or_public_page(struct page *page);
#else
static inline void put_zone_device_private_page(struct page *page)
static inline void put_zone_device_private_or_public_page(struct page *page)
{
}
#endif
#endif /* CONFIG_DEVICE_PRIVATE || CONFIG_DEVICE_PUBLIC */
static inline bool is_device_private_page(const struct page *page);
static inline bool is_device_public_page(const struct page *page);
DECLARE_STATIC_KEY_FALSE(device_private_key);
@ -834,8 +835,9 @@ static inline void put_page(struct page *page)
* include/linux/memremap.h and HMM for details.
*/
if (static_branch_unlikely(&device_private_key) &&
unlikely(is_device_private_page(page))) {
put_zone_device_private_page(page);
unlikely(is_device_private_page(page) ||
is_device_public_page(page))) {
put_zone_device_private_or_public_page(page);
return;
}
@ -1224,8 +1226,10 @@ struct zap_details {
pgoff_t last_index; /* Highest page->index to unmap */
};
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);
#define vm_normal_page(vma, addr, pte) _vm_normal_page(vma, addr, pte, false)
struct page *vm_normal_page_pmd(struct vm_area_struct *vma, unsigned long addr,
pmd_t pmd);

8
kernel/memremap.c
View File

@ -501,8 +501,8 @@ struct vmem_altmap *to_vmem_altmap(unsigned long memmap_start)
#endif /* CONFIG_ZONE_DEVICE */
#ifdef CONFIG_DEVICE_PRIVATE
void put_zone_device_private_page(struct page *page)
#if IS_ENABLED(CONFIG_DEVICE_PRIVATE) || IS_ENABLED(CONFIG_DEVICE_PUBLIC)
void put_zone_device_private_or_public_page(struct page *page)
{
int count = page_ref_dec_return(page);
@ -522,5 +522,5 @@ void put_zone_device_private_page(struct page *page)
} else if (!count)
__put_page(page);
}
EXPORT_SYMBOL(put_zone_device_private_page);
#endif /* CONFIG_DEVICE_PRIVATE */
EXPORT_SYMBOL(put_zone_device_private_or_public_page);
#endif /* CONFIG_DEVICE_PRIVATE || CONFIG_DEVICE_PUBLIC */

11
mm/Kconfig
View File

@ -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

7
mm/gup.c
View File

@ -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:

4
mm/hmm.c
View File

@ -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 */

2
mm/madvise.c
View File

@ -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;

12
mm/memcontrol.c
View File

@ -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;

46
mm/memory.c
View File

@ -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

55
mm/migrate.c
View File

@ -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;
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);
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.

11
mm/swap.c
View File

@ -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;