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. Changed since v1: - Kconfig and #if/#else cleanup Signed-off-by: Jérôme Glisse <jglisse@xxxxxxxxxx> Cc: Balbir Singh <balbirs@xxxxxxxxxxx> Cc: Aneesh Kumar <aneesh.kumar@xxxxxxxxxxxxxxxxxx> Cc: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx> Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> Cc: Dan Williams <dan.j.williams@xxxxxxxxx> Cc: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx> --- fs/proc/task_mmu.c | 2 +- include/linux/hmm.h | 4 ++-- include/linux/ioport.h | 1 + include/linux/memremap.h | 21 +++++++++++++++++ include/linux/mm.h | 16 ++++++++----- kernel/memremap.c | 11 ++++++--- mm/Kconfig | 11 +++++++++ mm/gup.c | 7 ++++++ mm/hmm.c | 4 ++-- mm/madvise.c | 2 +- mm/memory.c | 46 +++++++++++++++++++++++++++++++++---- mm/migrate.c | 60 ++++++++++++++++++++++++++++++++---------------- mm/swap.c | 11 +++++++++ 13 files changed, 156 insertions(+), 40 deletions(-) diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 957b6ea80d5f..1f38f2c7cc34 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -1182,7 +1182,7 @@ 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)) { diff --git a/include/linux/hmm.h b/include/linux/hmm.h index 458d0d6d82f3..a40288309fd2 100644 --- a/include/linux/hmm.h +++ b/include/linux/hmm.h @@ -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, @@ -443,7 +443,7 @@ 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! */ diff --git a/include/linux/ioport.h b/include/linux/ioport.h index 3a4f69137bc2..f5cf32e80041 100644 --- a/include/linux/ioport.h +++ b/include/linux/ioport.h @@ -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 */ diff --git a/include/linux/memremap.h b/include/linux/memremap.h index 2299cc2d387d..916ca1653ced 100644 --- a/include/linux/memremap.h +++ b/include/linux/memremap.h @@ -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_PERSISTENT = 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_CACHE_COHERENT 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 /** diff --git a/include/linux/mm.h b/include/linux/mm.h index 330a216ac315..8b72b122de93 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -797,14 +797,15 @@ 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); +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 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); @@ -830,8 +831,9 @@ 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; } @@ -1220,8 +1222,10 @@ 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); diff --git a/kernel/memremap.c b/kernel/memremap.c index e82456c39a6a..da74775f2247 100644 --- a/kernel/memremap.c +++ b/kernel/memremap.c @@ -466,7 +466,7 @@ struct vmem_altmap *to_vmem_altmap(unsigned long memmap_start) #ifdef CONFIG_DEVICE_PRIVATE -void put_zone_device_private_page(struct page *page) +void put_zone_device_private_or_public_page(struct page *page) { int count = page_ref_dec_return(page); @@ -474,10 +474,15 @@ void put_zone_device_private_page(struct page *page) * If refcount is 1 then page is freed and refcount is stable as nobody * holds a reference on the page. */ - if (count == 1) + if (count == 1) { + /* Clear Active bit in case of parallel mark_page_accessed */ + __ClearPageActive(page); + __ClearPageWaiters(page); + page->pgmap->page_free(page, page->pgmap->data); + } else if (!count) __put_page(page); } -EXPORT_SYMBOL(put_zone_device_private_page); +EXPORT_SYMBOL(put_zone_device_private_or_public_page); #endif /* CONFIG_DEVICE_PRIVATE */ diff --git a/mm/Kconfig b/mm/Kconfig index 3269ff1cc4cd..6002f1e40fcd 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -712,12 +712,23 @@ config ZONE_DEVICE 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). +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 23f01c40c88f..2f8e8604ff80 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -438,6 +438,13 @@ 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 4e01c9ba9cc1..eadf70829c34 100644 --- a/mm/hmm.c +++ b/mm/hmm.c @@ -747,7 +747,7 @@ 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) { @@ -1190,4 +1190,4 @@ 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 9976852f1e1c..197277156ce3 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -343,7 +343,7 @@ 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/memory.c b/mm/memory.c index 4fcdab3ec525..cee2bed01aa0 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -789,8 +789,8 @@ 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); @@ -801,8 +801,31 @@ 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; } @@ -983,6 +1006,19 @@ 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: @@ -1236,7 +1272,7 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb, 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 643ea61ca9bb..f9ae57f0c7a1 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -229,12 +229,19 @@ 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 (pte_swp_soft_dirty(*pvmw.pte)) - pte = pte_mksoft_dirty(pte); + 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); + if (pte_swp_soft_dirty(*pvmw.pte)) + pte = pte_mksoft_dirty(pte); + } +#if IS_ENABLED(CONFIG_DEVICE_PUBLIC) + else if (is_device_public_page(new)) { + pte = pte_mkdevmap(pte); + flush_dcache_page(new); + } +#endif /* IS_ENABLED(CONFIG_DEVICE_PUBLIC) */ } else flush_dcache_page(new); @@ -408,12 +415,11 @@ 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 */ @@ -2087,7 +2093,6 @@ int migrate_misplaced_transhuge_page(struct mm_struct *mm, #endif /* CONFIG_NUMA */ - struct migrate_vma { struct vm_area_struct *vma; unsigned long *dst; @@ -2186,7 +2191,7 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp, if (is_write_device_private_entry(entry)) mpfn |= MIGRATE_PFN_WRITE; } else { - 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; } @@ -2311,13 +2316,18 @@ static bool migrate_vma_check_page(struct page *page) /* Page from ZONE_DEVICE have one extra reference */ if (is_zone_device_page(page)) { - if (is_device_private_page(page)) { + if (is_device_private_page(page) || + is_device_public_page(page)) extra++; - } else + else /* Other ZONE_DEVICE memory type are not supported */ return false; } + /* For file back page */ + if (page_mapping(page)) + extra += 1 + page_has_private(page); + if ((page_count(page) - extra) > page_mapcount(page)) return false; @@ -2541,11 +2551,21 @@ 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); + } +#if IS_ENABLED(CONFIG_DEVICE_PUBLIC) + 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); + } +#endif /* IS_ENABLED(CONFIG_DEVICE_PUBLIC) */ } else { entry = mk_pte(page, vma->vm_page_prot); if (vma->vm_flags & VM_WRITE) @@ -2631,7 +2651,7 @@ 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 4f44dbd7f780..212370d6cb23 100644 --- a/mm/swap.c +++ b/mm/swap.c @@ -760,6 +760,17 @@ 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; -- 2.13.0 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. 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