From 734c15700cdf9062ae98d8b131c6fe873dfad26d Mon Sep 17 00:00:00 2001 From: Oscar Salvador Date: Tue, 22 Mar 2022 14:47:37 -0700 Subject: mm: only re-generate demotion targets when a numa node changes its N_CPU state Abhishek reported that after patch [1], hotplug operations are taking roughly double the expected time. [2] The reason behind is that the CPU callbacks that migrate_on_reclaim_init() sets always call set_migration_target_nodes() whenever a CPU is brought up/down. But we only care about numa nodes going from having cpus to become cpuless, and vice versa, as that influences the demotion_target order. We do already have two CPU callbacks (vmstat_cpu_online() and vmstat_cpu_dead()) that check exactly that, so get rid of the CPU callbacks in migrate_on_reclaim_init() and only call set_migration_target_nodes() from vmstat_cpu_{dead,online}() whenever a numa node change its N_CPU state. [1] https://lore.kernel.org/linux-mm/20210721063926.3024591-2-ying.huang@intel.com/ [2] https://lore.kernel.org/linux-mm/eb438ddd-2919-73d4-bd9f-b7eecdd9577a@linux.vnet.ibm.com/ [osalvador@suse.de: add feedback from Huang Ying] Link: https://lkml.kernel.org/r/20220314150945.12694-1-osalvador@suse.de Link: https://lkml.kernel.org/r/20220310120749.23077-1-osalvador@suse.de Fixes: 884a6e5d1f93b ("mm/migrate: update node demotion order on hotplug events") Signed-off-by: Oscar Salvador Reviewed-by: Baolin Wang Tested-by: Baolin Wang Reported-by: Abhishek Goel Cc: Dave Hansen Cc: "Huang, Ying" Cc: Abhishek Goel Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/migrate.h | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'include/linux/migrate.h') diff --git a/include/linux/migrate.h b/include/linux/migrate.h index db96e10eb8da..90e75d5a54d6 100644 --- a/include/linux/migrate.h +++ b/include/linux/migrate.h @@ -48,7 +48,15 @@ int folio_migrate_mapping(struct address_space *mapping, struct folio *newfolio, struct folio *folio, int extra_count); extern bool numa_demotion_enabled; +extern void migrate_on_reclaim_init(void); +#ifdef CONFIG_HOTPLUG_CPU +extern void set_migration_target_nodes(void); #else +static inline void set_migration_target_nodes(void) {} +#endif +#else + +static inline void set_migration_target_nodes(void) {} static inline void putback_movable_pages(struct list_head *l) {} static inline int migrate_pages(struct list_head *l, new_page_t new, -- cgit v1.2.3 From 7d6e2d96384556a4f30547803be1f606eb805a62 Mon Sep 17 00:00:00 2001 From: Oscar Salvador Date: Thu, 28 Apr 2022 23:16:09 -0700 Subject: mm: untangle config dependencies for demote-on-reclaim At the time demote-on-reclaim was introduced, it was tied to CONFIG_HOTPLUG_CPU + CONFIG_MIGRATE, but that is not really accurate. The only two things we need to depend on are CONFIG_NUMA + CONFIG_MIGRATE, so clean this up. Furthermore, we only register the hotplug memory notifier when the system has CONFIG_MEMORY_HOTPLUG. Link: https://lkml.kernel.org/r/20220322224016.4574-1-osalvador@suse.de Signed-off-by: Oscar Salvador Suggested-by: "Huang, Ying" Reviewed-by: "Huang, Ying" Cc: Dave Hansen Cc: Abhishek Goel Cc: Baolin Wang Signed-off-by: Andrew Morton --- include/linux/migrate.h | 34 +++++++++++++++------------------- 1 file changed, 15 insertions(+), 19 deletions(-) (limited to 'include/linux/migrate.h') diff --git a/include/linux/migrate.h b/include/linux/migrate.h index 90e75d5a54d6..2707bfd43a0d 100644 --- a/include/linux/migrate.h +++ b/include/linux/migrate.h @@ -47,17 +47,8 @@ void folio_migrate_copy(struct folio *newfolio, struct folio *folio); int folio_migrate_mapping(struct address_space *mapping, struct folio *newfolio, struct folio *folio, int extra_count); -extern bool numa_demotion_enabled; -extern void migrate_on_reclaim_init(void); -#ifdef CONFIG_HOTPLUG_CPU -extern void set_migration_target_nodes(void); -#else -static inline void set_migration_target_nodes(void) {} -#endif #else -static inline void set_migration_target_nodes(void) {} - static inline void putback_movable_pages(struct list_head *l) {} static inline int migrate_pages(struct list_head *l, new_page_t new, free_page_t free, unsigned long private, enum migrate_mode mode, @@ -82,9 +73,23 @@ static inline int migrate_huge_page_move_mapping(struct address_space *mapping, return -ENOSYS; } -#define numa_demotion_enabled false #endif /* CONFIG_MIGRATION */ +#if defined(CONFIG_MIGRATION) && defined(CONFIG_NUMA) +extern void set_migration_target_nodes(void); +extern void migrate_on_reclaim_init(void); +extern bool numa_demotion_enabled; +extern int next_demotion_node(int node); +#else +static inline void set_migration_target_nodes(void) {} +static inline void migrate_on_reclaim_init(void) {} +static inline int next_demotion_node(int node) +{ + return NUMA_NO_NODE; +} +#define numa_demotion_enabled false +#endif + #ifdef CONFIG_COMPACTION extern int PageMovable(struct page *page); extern void __SetPageMovable(struct page *page, struct address_space *mapping); @@ -172,15 +177,6 @@ struct migrate_vma { int migrate_vma_setup(struct migrate_vma *args); void migrate_vma_pages(struct migrate_vma *migrate); void migrate_vma_finalize(struct migrate_vma *migrate); -int next_demotion_node(int node); - -#else /* CONFIG_MIGRATION disabled: */ - -static inline int next_demotion_node(int node) -{ - return NUMA_NO_NODE; -} - #endif /* CONFIG_MIGRATION */ #endif /* _LINUX_MIGRATE_H */ -- cgit v1.2.3 From 8b463be3a0241558071e6ba9bf11e4bf42ccc856 Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Thu, 12 May 2022 20:23:05 -0700 Subject: mm: add folio_test_movable() This is the folio equivalent of PageMovable() which is needed to convert mm/migrate.c to folios. Link: https://lkml.kernel.org/r/20220504182857.4013401-26-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: Christoph Hellwig Signed-off-by: Andrew Morton --- include/linux/migrate.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'include/linux/migrate.h') diff --git a/include/linux/migrate.h b/include/linux/migrate.h index 2707bfd43a0d..069a89e847f3 100644 --- a/include/linux/migrate.h +++ b/include/linux/migrate.h @@ -105,6 +105,11 @@ static inline void __ClearPageMovable(struct page *page) } #endif +static inline bool folio_test_movable(struct folio *folio) +{ + return PageMovable(&folio->page); +} + #ifdef CONFIG_NUMA_BALANCING extern int migrate_misplaced_page(struct page *page, struct vm_area_struct *vma, int node); -- cgit v1.2.3 From dd19e6d8ffaa1289d75d7833de97faf1b6b2c8e4 Mon Sep 17 00:00:00 2001 From: Alex Sierra Date: Fri, 15 Jul 2022 10:05:12 -0500 Subject: 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. Link: https://lkml.kernel.org/r/20220715150521.18165-6-alex.sierra@amd.com Signed-off-by: Alex Sierra Signed-off-by: Christoph Hellwig Acked-by: Felix Kuehling Reviewed-by: Alistair Poppple Reviewed-by: David Hildenbrand Cc: Jason Gunthorpe Cc: Jerome Glisse Cc: Matthew Wilcox Cc: Ralph Campbell Signed-off-by: Andrew Morton --- include/linux/migrate.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/migrate.h') 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 { -- cgit v1.2.3 From 68f2736a858324c3ec852f6c2cddd9d1c777357d Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Tue, 7 Jun 2022 15:38:48 -0400 Subject: mm: Convert all PageMovable users to movable_operations These drivers are rather uncomfortably hammered into the address_space_operations hole. They aren't filesystems and don't behave like filesystems. They just need their own movable_operations structure, which we can point to directly from page->mapping. Signed-off-by: Matthew Wilcox (Oracle) --- include/linux/migrate.h | 56 ++++++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 51 insertions(+), 5 deletions(-) (limited to 'include/linux/migrate.h') diff --git a/include/linux/migrate.h b/include/linux/migrate.h index 069a89e847f3..82c735ba6109 100644 --- a/include/linux/migrate.h +++ b/include/linux/migrate.h @@ -19,6 +19,43 @@ struct migration_target_control; */ #define MIGRATEPAGE_SUCCESS 0 +/** + * struct movable_operations - Driver page migration + * @isolate_page: + * The VM calls this function to prepare the page to be moved. The page + * is locked and the driver should not unlock it. The driver should + * return ``true`` if the page is movable and ``false`` if it is not + * currently movable. After this function returns, the VM uses the + * page->lru field, so the driver must preserve any information which + * is usually stored here. + * + * @migrate_page: + * After isolation, the VM calls this function with the isolated + * @src page. The driver should copy the contents of the + * @src page to the @dst page and set up the fields of @dst page. + * Both pages are locked. + * If page migration is successful, the driver should call + * __ClearPageMovable(@src) and return MIGRATEPAGE_SUCCESS. + * If the driver cannot migrate the page at the moment, it can return + * -EAGAIN. The VM interprets this as a temporary migration failure and + * will retry it later. Any other error value is a permanent migration + * failure and migration will not be retried. + * The driver shouldn't touch the @src->lru field while in the + * migrate_page() function. It may write to @dst->lru. + * + * @putback_page: + * If migration fails on the isolated page, the VM informs the driver + * that the page is no longer a candidate for migration by calling + * this function. The driver should put the isolated page back into + * its own data structure. + */ +struct movable_operations { + bool (*isolate_page)(struct page *, isolate_mode_t); + int (*migrate_page)(struct page *dst, struct page *src, + enum migrate_mode); + void (*putback_page)(struct page *); +}; + /* Defined in mm/debug.c: */ extern const char *migrate_reason_names[MR_TYPES]; @@ -91,13 +128,13 @@ static inline int next_demotion_node(int node) #endif #ifdef CONFIG_COMPACTION -extern int PageMovable(struct page *page); -extern void __SetPageMovable(struct page *page, struct address_space *mapping); -extern void __ClearPageMovable(struct page *page); +bool PageMovable(struct page *page); +void __SetPageMovable(struct page *page, const struct movable_operations *ops); +void __ClearPageMovable(struct page *page); #else -static inline int PageMovable(struct page *page) { return 0; } +static inline bool PageMovable(struct page *page) { return false; } static inline void __SetPageMovable(struct page *page, - struct address_space *mapping) + const struct movable_operations *ops) { } static inline void __ClearPageMovable(struct page *page) @@ -110,6 +147,15 @@ static inline bool folio_test_movable(struct folio *folio) return PageMovable(&folio->page); } +static inline +const struct movable_operations *page_movable_ops(struct page *page) +{ + VM_BUG_ON(!__PageMovable(page)); + + return (const struct movable_operations *) + ((unsigned long)page->mapping - PAGE_MAPPING_MOVABLE); +} + #ifdef CONFIG_NUMA_BALANCING extern int migrate_misplaced_page(struct page *page, struct vm_area_struct *vma, int node); -- cgit v1.2.3 From 541846502f4fe826cd7c16e4784695ac90736585 Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Mon, 6 Jun 2022 10:27:41 -0400 Subject: mm/migrate: Convert migrate_page() to migrate_folio() Convert all callers to pass a folio. Most have the folio already available. Switch all users from aops->migratepage to aops->migrate_folio. Also turn the documentation into kerneldoc. Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: Christoph Hellwig Acked-by: David Sterba --- include/linux/migrate.h | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'include/linux/migrate.h') diff --git a/include/linux/migrate.h b/include/linux/migrate.h index 82c735ba6109..c9986d5da335 100644 --- a/include/linux/migrate.h +++ b/include/linux/migrate.h @@ -62,9 +62,8 @@ extern const char *migrate_reason_names[MR_TYPES]; #ifdef CONFIG_MIGRATION extern void putback_movable_pages(struct list_head *l); -extern int migrate_page(struct address_space *mapping, - struct page *newpage, struct page *page, - enum migrate_mode mode); +int migrate_folio(struct address_space *mapping, struct folio *dst, + struct folio *src, enum migrate_mode mode); extern int migrate_pages(struct list_head *l, new_page_t new, free_page_t free, unsigned long private, enum migrate_mode mode, int reason, unsigned int *ret_succeeded); -- cgit v1.2.3 From b890ec2a2c2d962f71ba31ae291f8fd252b46258 Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Mon, 6 Jun 2022 10:47:21 -0400 Subject: hugetlb: Convert to migrate_folio This involves converting migrate_huge_page_move_mapping(). We also need a folio variant of hugetlb_set_page_subpool(), but that's for a later patch. Signed-off-by: Matthew Wilcox (Oracle) Acked-by: Muchun Song Reviewed-by: Mike Kravetz --- include/linux/migrate.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'include/linux/migrate.h') diff --git a/include/linux/migrate.h b/include/linux/migrate.h index c9986d5da335..13f793309b75 100644 --- a/include/linux/migrate.h +++ b/include/linux/migrate.h @@ -72,8 +72,8 @@ extern int isolate_movable_page(struct page *page, isolate_mode_t mode); extern void migrate_page_states(struct page *newpage, struct page *page); extern void migrate_page_copy(struct page *newpage, struct page *page); -extern int migrate_huge_page_move_mapping(struct address_space *mapping, - struct page *newpage, struct page *page); +int migrate_huge_page_move_mapping(struct address_space *mapping, + struct folio *dst, struct folio *src); extern int migrate_page_move_mapping(struct address_space *mapping, struct page *newpage, struct page *page, int extra_count); void migration_entry_wait_on_locked(swp_entry_t entry, pte_t *ptep, @@ -104,7 +104,7 @@ static inline void migrate_page_copy(struct page *newpage, struct page *page) {} static inline int migrate_huge_page_move_mapping(struct address_space *mapping, - struct page *newpage, struct page *page) + struct folio *dst, struct folio *src) { return -ENOSYS; } -- cgit v1.2.3 From 9800562f2ab41656b0bdc2a41c77ab3f6dfdd6fc Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Mon, 6 Jun 2022 13:29:10 -0400 Subject: mm/folio-compat: Remove migration compatibility functions migrate_page_move_mapping(), migrate_page_copy() and migrate_page_states() are all now unused after converting all the filesystems from aops->migratepage() to aops->migrate_folio(). Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: Christoph Hellwig --- include/linux/migrate.h | 11 ----------- 1 file changed, 11 deletions(-) (limited to 'include/linux/migrate.h') diff --git a/include/linux/migrate.h b/include/linux/migrate.h index 13f793309b75..ae5bb67a9ba1 100644 --- a/include/linux/migrate.h +++ b/include/linux/migrate.h @@ -70,12 +70,8 @@ extern int migrate_pages(struct list_head *l, new_page_t new, free_page_t free, extern struct page *alloc_migration_target(struct page *page, unsigned long private); extern int isolate_movable_page(struct page *page, isolate_mode_t mode); -extern void migrate_page_states(struct page *newpage, struct page *page); -extern void migrate_page_copy(struct page *newpage, struct page *page); int migrate_huge_page_move_mapping(struct address_space *mapping, struct folio *dst, struct folio *src); -extern int migrate_page_move_mapping(struct address_space *mapping, - struct page *newpage, struct page *page, int extra_count); void migration_entry_wait_on_locked(swp_entry_t entry, pte_t *ptep, spinlock_t *ptl); void folio_migrate_flags(struct folio *newfolio, struct folio *folio); @@ -96,13 +92,6 @@ static inline struct page *alloc_migration_target(struct page *page, static inline int isolate_movable_page(struct page *page, isolate_mode_t mode) { return -EBUSY; } -static inline void migrate_page_states(struct page *newpage, struct page *page) -{ -} - -static inline void migrate_page_copy(struct page *newpage, - struct page *page) {} - static inline int migrate_huge_page_move_mapping(struct address_space *mapping, struct folio *dst, struct folio *src) { -- cgit v1.2.3 From 9195244022788935eac0df16132394ffa5613542 Mon Sep 17 00:00:00 2001 From: "Aneesh Kumar K.V" Date: Thu, 18 Aug 2022 18:40:34 +0530 Subject: mm/demotion: move memory demotion related code This moves memory demotion related code to mm/memory-tiers.c. No functional change in this patch. Link: https://lkml.kernel.org/r/20220818131042.113280-3-aneesh.kumar@linux.ibm.com Signed-off-by: Aneesh Kumar K.V Reviewed-by: "Huang, Ying" Acked-by: Wei Xu Cc: Alistair Popple Cc: Bharata B Rao Cc: Dan Williams Cc: Dave Hansen Cc: Davidlohr Bueso Cc: Hesham Almatary Cc: Jagdish Gediya Cc: Johannes Weiner Cc: Jonathan Cameron Cc: Michal Hocko Cc: Tim Chen Cc: Yang Shi Cc: SeongJae Park Signed-off-by: Andrew Morton --- include/linux/migrate.h | 2 -- 1 file changed, 2 deletions(-) (limited to 'include/linux/migrate.h') diff --git a/include/linux/migrate.h b/include/linux/migrate.h index 22c0a0cf5e0c..96f8c84413fe 100644 --- a/include/linux/migrate.h +++ b/include/linux/migrate.h @@ -103,7 +103,6 @@ static inline int migrate_huge_page_move_mapping(struct address_space *mapping, #if defined(CONFIG_MIGRATION) && defined(CONFIG_NUMA) extern void set_migration_target_nodes(void); extern void migrate_on_reclaim_init(void); -extern bool numa_demotion_enabled; extern int next_demotion_node(int node); #else static inline void set_migration_target_nodes(void) {} @@ -112,7 +111,6 @@ static inline int next_demotion_node(int node) { return NUMA_NO_NODE; } -#define numa_demotion_enabled false #endif #ifdef CONFIG_COMPACTION -- cgit v1.2.3 From 6c542ab75714fe90dae292aeb3e91ac53f5ff599 Mon Sep 17 00:00:00 2001 From: "Aneesh Kumar K.V" Date: Thu, 18 Aug 2022 18:40:37 +0530 Subject: mm/demotion: build demotion targets based on explicit memory tiers This patch switch the demotion target building logic to use memory tiers instead of NUMA distance. All N_MEMORY NUMA nodes will be placed in the default memory tier and additional memory tiers will be added by drivers like dax kmem. This patch builds the demotion target for a NUMA node by looking at all memory tiers below the tier to which the NUMA node belongs. The closest node in the immediately following memory tier is used as a demotion target. Since we are now only building demotion target for N_MEMORY NUMA nodes the CPU hotplug calls are removed in this patch. Link: https://lkml.kernel.org/r/20220818131042.113280-6-aneesh.kumar@linux.ibm.com Signed-off-by: Aneesh Kumar K.V Reviewed-by: "Huang, Ying" Acked-by: Wei Xu Cc: Alistair Popple Cc: Bharata B Rao Cc: Dan Williams Cc: Dave Hansen Cc: Davidlohr Bueso Cc: Hesham Almatary Cc: Jagdish Gediya Cc: Johannes Weiner Cc: Jonathan Cameron Cc: Michal Hocko Cc: Tim Chen Cc: Yang Shi Cc: SeongJae Park Signed-off-by: Andrew Morton --- include/linux/migrate.h | 13 ------------- 1 file changed, 13 deletions(-) (limited to 'include/linux/migrate.h') diff --git a/include/linux/migrate.h b/include/linux/migrate.h index 96f8c84413fe..704a04f5a074 100644 --- a/include/linux/migrate.h +++ b/include/linux/migrate.h @@ -100,19 +100,6 @@ static inline int migrate_huge_page_move_mapping(struct address_space *mapping, #endif /* CONFIG_MIGRATION */ -#if defined(CONFIG_MIGRATION) && defined(CONFIG_NUMA) -extern void set_migration_target_nodes(void); -extern void migrate_on_reclaim_init(void); -extern int next_demotion_node(int node); -#else -static inline void set_migration_target_nodes(void) {} -static inline void migrate_on_reclaim_init(void) {} -static inline int next_demotion_node(int node) -{ - return NUMA_NO_NODE; -} -#endif - #ifdef CONFIG_COMPACTION bool PageMovable(struct page *page); void __SetPageMovable(struct page *page, const struct movable_operations *ops); -- cgit v1.2.3 From 16ce101db85db694a91380aa4c89b25530871d33 Mon Sep 17 00:00:00 2001 From: Alistair Popple Date: Wed, 28 Sep 2022 22:01:15 +1000 Subject: mm/memory.c: fix race when faulting a device private page MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Patch series "Fix several device private page reference counting issues", v2 This series aims to fix a number of page reference counting issues in drivers dealing with device private ZONE_DEVICE pages. These result in use-after-free type bugs, either from accessing a struct page which no longer exists because it has been removed or accessing fields within the struct page which are no longer valid because the page has been freed. During normal usage it is unlikely these will cause any problems. However without these fixes it is possible to crash the kernel from userspace. These crashes can be triggered either by unloading the kernel module or unbinding the device from the driver prior to a userspace task exiting. In modules such as Nouveau it is also possible to trigger some of these issues by explicitly closing the device file-descriptor prior to the task exiting and then accessing device private memory. This involves some minor changes to both PowerPC and AMD GPU code. Unfortunately I lack hardware to test either of those so any help there would be appreciated. The changes mimic what is done in for both Nouveau and hmm-tests though so I doubt they will cause problems. This patch (of 8): When the CPU tries to access a device private page the migrate_to_ram() callback associated with the pgmap for the page is called. However no reference is taken on the faulting page. Therefore a concurrent migration of the device private page can free the page and possibly the underlying pgmap. This results in a race which can crash the kernel due to the migrate_to_ram() function pointer becoming invalid. It also means drivers can't reliably read the zone_device_data field because the page may have been freed with memunmap_pages(). Close the race by getting a reference on the page while holding the ptl to ensure it has not been freed. Unfortunately the elevated reference count will cause the migration required to handle the fault to fail. To avoid this failure pass the faulting page into the migrate_vma functions so that if an elevated reference count is found it can be checked to see if it's expected or not. [mpe@ellerman.id.au: fix build] Link: https://lkml.kernel.org/r/87fsgbf3gh.fsf@mpe.ellerman.id.au Link: https://lkml.kernel.org/r/cover.60659b549d8509ddecafad4f498ee7f03bb23c69.1664366292.git-series.apopple@nvidia.com Link: https://lkml.kernel.org/r/d3e813178a59e565e8d78d9b9a4e2562f6494f90.1664366292.git-series.apopple@nvidia.com Signed-off-by: Alistair Popple Acked-by: Felix Kuehling Cc: Jason Gunthorpe Cc: John Hubbard Cc: Ralph Campbell Cc: Michael Ellerman Cc: Lyude Paul Cc: Alex Deucher Cc: Alex Sierra Cc: Ben Skeggs Cc: Christian König Cc: Dan Williams Cc: David Hildenbrand Cc: "Huang, Ying" Cc: Matthew Wilcox Cc: Yang Shi Cc: Zi Yan Signed-off-by: Andrew Morton --- include/linux/migrate.h | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'include/linux/migrate.h') diff --git a/include/linux/migrate.h b/include/linux/migrate.h index 704a04f5a074..52090d1f9230 100644 --- a/include/linux/migrate.h +++ b/include/linux/migrate.h @@ -62,6 +62,8 @@ extern const char *migrate_reason_names[MR_TYPES]; #ifdef CONFIG_MIGRATION extern void putback_movable_pages(struct list_head *l); +int migrate_folio_extra(struct address_space *mapping, struct folio *dst, + struct folio *src, enum migrate_mode mode, int extra_count); int migrate_folio(struct address_space *mapping, struct folio *dst, struct folio *src, enum migrate_mode mode); extern int migrate_pages(struct list_head *l, new_page_t new, free_page_t free, @@ -197,6 +199,12 @@ struct migrate_vma { */ void *pgmap_owner; unsigned long flags; + + /* + * Set to vmf->page if this is being called to migrate a page as part of + * a migrate_to_ram() callback. + */ + struct page *fault_page; }; int migrate_vma_setup(struct migrate_vma *args); -- cgit v1.2.3 From e778406b40dbb1342a1888cd751ca9d2982a12e2 Mon Sep 17 00:00:00 2001 From: Alistair Popple Date: Wed, 28 Sep 2022 22:01:19 +1000 Subject: mm/migrate_device.c: add migrate_device_range() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Device drivers can use the migrate_vma family of functions to migrate existing private anonymous mappings to device private pages. These pages are backed by memory on the device with drivers being responsible for copying data to and from device memory. Device private pages are freed via the pgmap->page_free() callback when they are unmapped and their refcount drops to zero. Alternatively they may be freed indirectly via migration back to CPU memory in response to a pgmap->migrate_to_ram() callback called whenever the CPU accesses an address mapped to a device private page. In other words drivers cannot control the lifetime of data allocated on the devices and must wait until these pages are freed from userspace. This causes issues when memory needs to reclaimed on the device, either because the device is going away due to a ->release() callback or because another user needs to use the memory. Drivers could use the existing migrate_vma functions to migrate data off the device. However this would require them to track the mappings of each page which is both complicated and not always possible. Instead drivers need to be able to migrate device pages directly so they can free up device memory. To allow that this patch introduces the migrate_device family of functions which are functionally similar to migrate_vma but which skips the initial lookup based on mapping. Link: https://lkml.kernel.org/r/868116aab70b0c8ee467d62498bb2cf0ef907295.1664366292.git-series.apopple@nvidia.com Signed-off-by: Alistair Popple Cc: "Huang, Ying" Cc: Zi Yan Cc: Matthew Wilcox Cc: Yang Shi Cc: David Hildenbrand Cc: Ralph Campbell Cc: John Hubbard Cc: Alex Deucher Cc: Alex Sierra Cc: Ben Skeggs Cc: Christian König Cc: Dan Williams Cc: Felix Kuehling Cc: Jason Gunthorpe Cc: Lyude Paul Cc: Michael Ellerman Signed-off-by: Andrew Morton --- include/linux/migrate.h | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'include/linux/migrate.h') diff --git a/include/linux/migrate.h b/include/linux/migrate.h index 52090d1f9230..3ef77f52a4f0 100644 --- a/include/linux/migrate.h +++ b/include/linux/migrate.h @@ -210,6 +210,13 @@ struct migrate_vma { int migrate_vma_setup(struct migrate_vma *args); void migrate_vma_pages(struct migrate_vma *migrate); void migrate_vma_finalize(struct migrate_vma *migrate); +int migrate_device_range(unsigned long *src_pfns, unsigned long start, + unsigned long npages); +void migrate_device_pages(unsigned long *src_pfns, unsigned long *dst_pfns, + unsigned long npages); +void migrate_device_finalize(unsigned long *src_pfns, + unsigned long *dst_pfns, unsigned long npages); + #endif /* CONFIG_MIGRATION */ #endif /* _LINUX_MIGRATE_H */ -- cgit v1.2.3