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Commit df6ad698 authored by Jérôme Glisse's avatar Jérôme Glisse Committed by Linus Torvalds
Browse files

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: default avatarJérôme 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 8315ada7

fs/proc/task_mmu.c

+1 −1
Original line number Diff line number Diff line
@@ -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)) {

include/linux/hmm.h

+2 −2
Original line number Diff line number Diff line
@@ -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! */

include/linux/ioport.h

+1 −0
Original line number Diff line number Diff line
@@ -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 */

include/linux/memremap.h

+21 −0
Original line number Diff line number Diff line
@@ -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



/**

include/linux/mm.h

+12 −8
Original line number Diff line number Diff line
@@ -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);