From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f200.google.com (mail-pf0-f200.google.com [209.85.192.200]) by kanga.kvack.org (Postfix) with ESMTP id 8E2156B0009 for ; Tue, 24 Apr 2018 19:43:23 -0400 (EDT) Received: by mail-pf0-f200.google.com with SMTP id e9so14217631pfn.16 for ; Tue, 24 Apr 2018 16:43:23 -0700 (PDT) Received: from mga17.intel.com (mga17.intel.com. [192.55.52.151]) by mx.google.com with ESMTPS id f1si12327057pgc.495.2018.04.24.16.43.21 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 24 Apr 2018 16:43:22 -0700 (PDT) Subject: [PATCH v9 4/9] mm, dev_pagemap: introduce CONFIG_DEV_PAGEMAP_OPS From: Dan Williams Date: Tue, 24 Apr 2018 16:33:24 -0700 Message-ID: <152461280458.17530.2579145654191440673.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <152461278149.17530.2867511144531572045.stgit@dwillia2-desk3.amr.corp.intel.com> References: <152461278149.17530.2867511144531572045.stgit@dwillia2-desk3.amr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org List-ID: To: linux-nvdimm@lists.01.org Cc: Martin Schwidefsky , Heiko Carstens , Michal Hocko , kbuild test robot , Thomas Meyer , Christoph Hellwig , =?utf-8?b?SsOpcsO0bWU=?= Glisse , Jan Kara , david@fromorbit.com, linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org, linux-mm@kvack.orgjack@suse.czhch@lst.de The HMM sub-system extended dev_pagemap to arrange a callback when a dev_pagemap managed page is freed. Since a dev_pagemap page is free / idle when its reference count is 1 it requires an additional branch to check the page-type at put_page() time. Given put_page() is a hot-path we do not want to incur that check if HMM is not in use, so a static branch is used to avoid that overhead when not necessary. Now, the FS_DAX implementation wants to reuse this mechanism for receiving dev_pagemap ->page_free() callbacks. Rework the HMM-specific static-key into a generic mechanism that either HMM or FS_DAX code paths can enable. For ARCH=um builds, and any other arch that lacks ZONE_DEVICE support, care must be taken to compile out the DEV_PAGEMAP_OPS infrastructure. However, we still need to support FS_DAX in the FS_DAX_LIMITED case implemented by the s390/dcssblk driver. Cc: Martin Schwidefsky Cc: Heiko Carstens Cc: Michal Hocko Reported-by: kbuild test robot Reported-by: Thomas Meyer Reviewed-by: Christoph Hellwig Reviewed-by: "JA(C)rA'me Glisse" Reviewed-by: Jan Kara Signed-off-by: Dan Williams --- drivers/dax/super.c | 4 ++- fs/Kconfig | 1 + include/linux/dax.h | 48 +++++++++++++++++-------------- include/linux/memremap.h | 17 ----------- include/linux/mm.h | 71 ++++++++++++++++++++++++++++++++++------------ kernel/memremap.c | 30 +++++++++++++++++-- mm/Kconfig | 5 +++ mm/hmm.c | 13 +------- mm/swap.c | 3 +- 9 files changed, 118 insertions(+), 74 deletions(-) diff --git a/drivers/dax/super.c b/drivers/dax/super.c index e4864f319e16..86b3806ea35b 100644 --- a/drivers/dax/super.c +++ b/drivers/dax/super.c @@ -164,7 +164,7 @@ struct dax_device { const struct dax_operations *ops; }; -#if IS_ENABLED(CONFIG_FS_DAX) +#if IS_ENABLED(CONFIG_FS_DAX) && IS_ENABLED(CONFIG_DEV_PAGEMAP_OPS) static void generic_dax_pagefree(struct page *page, void *data) { /* TODO: wakeup page-idle waiters */ @@ -191,6 +191,7 @@ static struct dax_device *__fs_dax_claim(struct dax_device *dax_dev, return NULL; } + dev_pagemap_get_ops(); pgmap->type = MEMORY_DEVICE_FS_DAX; pgmap->page_free = generic_dax_pagefree; pgmap->data = owner; @@ -223,6 +224,7 @@ static void __fs_dax_release(struct dax_device *dax_dev, void *owner) pgmap->type = MEMORY_DEVICE_HOST; pgmap->page_free = NULL; pgmap->data = NULL; + dev_pagemap_put_ops(); mutex_unlock(&devmap_lock); } diff --git a/fs/Kconfig b/fs/Kconfig index bc821a86d965..1e050e012eb9 100644 --- a/fs/Kconfig +++ b/fs/Kconfig @@ -38,6 +38,7 @@ config FS_DAX bool "Direct Access (DAX) support" depends on MMU depends on !(ARM || MIPS || SPARC) + select DEV_PAGEMAP_OPS if (ZONE_DEVICE && !FS_DAX_LIMITED) select FS_IOMAP select DAX help diff --git a/include/linux/dax.h b/include/linux/dax.h index fe322d67856e..f1d6a8366e4b 100644 --- a/include/linux/dax.h +++ b/include/linux/dax.h @@ -4,6 +4,7 @@ #include #include +#include #include #include #include @@ -95,26 +96,6 @@ static inline void fs_put_dax(struct dax_device *dax_dev) int dax_writeback_mapping_range(struct address_space *mapping, struct block_device *bdev, struct writeback_control *wbc); -struct dax_device *fs_dax_claim(struct dax_device *dax_dev, void *owner); -#ifdef CONFIG_BLOCK -static inline struct dax_device *fs_dax_claim_bdev(struct block_device *bdev, - void *owner) -{ - struct dax_device *dax_dev; - - if (!blk_queue_dax(bdev->bd_queue)) - return NULL; - dax_dev = fs_dax_get_by_host(bdev->bd_disk->disk_name); - return fs_dax_claim(dax_dev, owner); -} -#else -static inline struct dax_device *fs_dax_claim_bdev(struct block_device *bdev, - void *owner) -{ - return NULL; -} -#endif -void fs_dax_release(struct dax_device *dax_dev, void *owner); #else static inline int bdev_dax_supported(struct super_block *sb, int blocksize) { @@ -135,13 +116,35 @@ static inline int dax_writeback_mapping_range(struct address_space *mapping, { return -EOPNOTSUPP; } +#endif -static inline struct dax_device *fs_dax_claim(struct dax_device *dax_dev, +#if IS_ENABLED(CONFIG_FS_DAX) && IS_ENABLED(CONFIG_DEV_PAGEMAP_OPS) +struct dax_device *fs_dax_claim(struct dax_device *dax_dev, void *owner); +#ifdef CONFIG_BLOCK +static inline struct dax_device *fs_dax_claim_bdev(struct block_device *bdev, + void *owner) +{ + struct dax_device *dax_dev; + + if (!blk_queue_dax(bdev->bd_queue)) + return NULL; + dax_dev = fs_dax_get_by_host(bdev->bd_disk->disk_name); + return fs_dax_claim(dax_dev, owner); +} +#else +static inline struct dax_device *fs_dax_claim_bdev(struct block_device *bdev, void *owner) { return NULL; } - +#endif +void fs_dax_release(struct dax_device *dax_dev, void *owner); +#else +static inline struct dax_device *fs_dax_claim(struct dax_device *dax_dev, + void *owner) +{ + return dax_dev; +} #ifdef CONFIG_BLOCK static inline struct dax_device *fs_dax_claim_bdev(struct block_device *bdev, void *owner) @@ -157,6 +160,7 @@ static inline struct dax_device *fs_dax_claim_bdev(struct block_device *bdev, #endif static inline void fs_dax_release(struct dax_device *dax_dev, void *owner) { + fs_put_dax(dax_dev); } #endif diff --git a/include/linux/memremap.h b/include/linux/memremap.h index 02d6d042ee7f..8cc619fe347b 100644 --- a/include/linux/memremap.h +++ b/include/linux/memremap.h @@ -1,7 +1,6 @@ /* SPDX-License-Identifier: GPL-2.0 */ #ifndef _LINUX_MEMREMAP_H_ #define _LINUX_MEMREMAP_H_ -#include #include #include @@ -137,8 +136,6 @@ struct dev_pagemap *get_dev_pagemap(unsigned long pfn, unsigned long vmem_altmap_offset(struct vmem_altmap *altmap); void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns); - -static inline bool is_zone_device_page(const struct page *page); #else static inline void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap) @@ -169,20 +166,6 @@ static inline void vmem_altmap_free(struct vmem_altmap *altmap, } #endif /* CONFIG_ZONE_DEVICE */ -#if defined(CONFIG_DEVICE_PRIVATE) || defined(CONFIG_DEVICE_PUBLIC) -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; -} -#endif /* CONFIG_DEVICE_PRIVATE || CONFIG_DEVICE_PUBLIC */ - static inline void put_dev_pagemap(struct dev_pagemap *pgmap) { if (pgmap) diff --git a/include/linux/mm.h b/include/linux/mm.h index 1ac1f06a4be6..6e19265ee8f8 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -821,27 +821,65 @@ static inline bool is_zone_device_page(const struct page *page) } #endif -#if defined(CONFIG_DEVICE_PRIVATE) || defined(CONFIG_DEVICE_PUBLIC) -void put_zone_device_private_or_public_page(struct page *page); -DECLARE_STATIC_KEY_FALSE(device_private_key); -#define IS_HMM_ENABLED static_branch_unlikely(&device_private_key) -static inline bool is_device_private_page(const struct page *page); -static inline bool is_device_public_page(const struct page *page); -#else /* CONFIG_DEVICE_PRIVATE || CONFIG_DEVICE_PUBLIC */ -static inline void put_zone_device_private_or_public_page(struct page *page) +#ifdef CONFIG_DEV_PAGEMAP_OPS +void dev_pagemap_get_ops(void); +void dev_pagemap_put_ops(void); +void __put_devmap_managed_page(struct page *page); +DECLARE_STATIC_KEY_FALSE(devmap_managed_key); +static inline bool put_devmap_managed_page(struct page *page) +{ + if (!static_branch_unlikely(&devmap_managed_key)) + return false; + if (!is_zone_device_page(page)) + return false; + switch (page->pgmap->type) { + case MEMORY_DEVICE_PRIVATE: + case MEMORY_DEVICE_PUBLIC: + case MEMORY_DEVICE_FS_DAX: + __put_devmap_managed_page(page); + return true; + default: + break; + } + return false; +} + +static inline bool is_device_private_page(const struct page *page) { + return is_zone_device_page(page) && + page->pgmap->type == MEMORY_DEVICE_PRIVATE; } -#define IS_HMM_ENABLED 0 + +static inline bool is_device_public_page(const struct page *page) +{ + return is_zone_device_page(page) && + page->pgmap->type == MEMORY_DEVICE_PUBLIC; +} + +#else /* CONFIG_DEV_PAGEMAP_OPS */ +static inline void dev_pagemap_get_ops(void) +{ +} + +static inline void dev_pagemap_put_ops(void) +{ +} + +static inline bool put_devmap_managed_page(struct page *page) +{ + return false; +} + 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 /* CONFIG_DEVICE_PRIVATE || CONFIG_DEVICE_PUBLIC */ - +#endif /* CONFIG_DEV_PAGEMAP_OPS */ static inline void get_page(struct page *page) { @@ -859,16 +897,13 @@ static inline void put_page(struct page *page) page = compound_head(page); /* - * For private device pages we need to catch refcount transition from - * 2 to 1, when refcount reach one it means the private device page is - * free and we need to inform the device driver through callback. See + * For devmap managed pages we need to catch refcount transition from + * 2 to 1, when refcount reach one it means the page is free and we + * need to inform the device driver through callback. See * include/linux/memremap.h and HMM for details. */ - if (IS_HMM_ENABLED && unlikely(is_device_private_page(page) || - unlikely(is_device_public_page(page)))) { - put_zone_device_private_or_public_page(page); + if (put_devmap_managed_page(page)) return; - } if (put_page_testzero(page)) __put_page(page); diff --git a/kernel/memremap.c b/kernel/memremap.c index 37a9604133f6..faceb3359c23 100644 --- a/kernel/memremap.c +++ b/kernel/memremap.c @@ -301,8 +301,30 @@ struct dev_pagemap *get_dev_pagemap(unsigned long pfn, return pgmap; } -#if IS_ENABLED(CONFIG_DEVICE_PRIVATE) || IS_ENABLED(CONFIG_DEVICE_PUBLIC) -void put_zone_device_private_or_public_page(struct page *page) +#ifdef CONFIG_DEV_PAGEMAP_OPS +DEFINE_STATIC_KEY_FALSE(devmap_managed_key); +EXPORT_SYMBOL_GPL(devmap_managed_key); +static atomic_t devmap_enable; + +/* + * Toggle the static key for ->page_free() callbacks when dev_pagemap + * pages go idle. + */ +void dev_pagemap_get_ops(void) +{ + if (atomic_inc_return(&devmap_enable) == 1) + static_branch_enable(&devmap_managed_key); +} +EXPORT_SYMBOL_GPL(dev_pagemap_get_ops); + +void dev_pagemap_put_ops(void) +{ + if (atomic_dec_and_test(&devmap_enable)) + static_branch_disable(&devmap_managed_key); +} +EXPORT_SYMBOL_GPL(dev_pagemap_put_ops); + +void __put_devmap_managed_page(struct page *page) { int count = page_ref_dec_return(page); @@ -322,5 +344,5 @@ void put_zone_device_private_or_public_page(struct page *page) } else if (!count) __put_page(page); } -EXPORT_SYMBOL(put_zone_device_private_or_public_page); -#endif /* CONFIG_DEVICE_PRIVATE || CONFIG_DEVICE_PUBLIC */ +EXPORT_SYMBOL_GPL(__put_devmap_managed_page); +#endif /* CONFIG_DEV_PAGEMAP_OPS */ diff --git a/mm/Kconfig b/mm/Kconfig index d5004d82a1d6..bf9d6366bced 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -692,6 +692,9 @@ config ARCH_HAS_HMM config MIGRATE_VMA_HELPER bool +config DEV_PAGEMAP_OPS + bool + config HMM bool select MIGRATE_VMA_HELPER @@ -712,6 +715,7 @@ config DEVICE_PRIVATE bool "Unaddressable device memory (GPU memory, ...)" depends on ARCH_HAS_HMM select HMM + select DEV_PAGEMAP_OPS help Allows creation of struct pages to represent unaddressable device @@ -722,6 +726,7 @@ config DEVICE_PUBLIC bool "Addressable device memory (like GPU memory)" depends on ARCH_HAS_HMM select HMM + select DEV_PAGEMAP_OPS help Allows creation of struct pages to represent addressable device diff --git a/mm/hmm.c b/mm/hmm.c index 486dc394a5a3..de7b6bf77201 100644 --- a/mm/hmm.c +++ b/mm/hmm.c @@ -35,15 +35,6 @@ #define PA_SECTION_SIZE (1UL << PA_SECTION_SHIFT) -#if defined(CONFIG_DEVICE_PRIVATE) || defined(CONFIG_DEVICE_PUBLIC) -/* - * Device private memory see HMM (Documentation/vm/hmm.txt) or hmm.h - */ -DEFINE_STATIC_KEY_FALSE(device_private_key); -EXPORT_SYMBOL(device_private_key); -#endif /* CONFIG_DEVICE_PRIVATE || CONFIG_DEVICE_PUBLIC */ - - #if IS_ENABLED(CONFIG_HMM_MIRROR) static const struct mmu_notifier_ops hmm_mmu_notifier_ops; @@ -1167,7 +1158,7 @@ struct hmm_devmem *hmm_devmem_add(const struct hmm_devmem_ops *ops, resource_size_t addr; int ret; - static_branch_enable(&device_private_key); + dev_pagemap_get_ops(); devmem = devres_alloc_node(&hmm_devmem_release, sizeof(*devmem), GFP_KERNEL, dev_to_node(device)); @@ -1261,7 +1252,7 @@ struct hmm_devmem *hmm_devmem_add_resource(const struct hmm_devmem_ops *ops, if (res->desc != IORES_DESC_DEVICE_PUBLIC_MEMORY) return ERR_PTR(-EINVAL); - static_branch_enable(&device_private_key); + dev_pagemap_get_ops(); devmem = devres_alloc_node(&hmm_devmem_release, sizeof(*devmem), GFP_KERNEL, dev_to_node(device)); diff --git a/mm/swap.c b/mm/swap.c index 3dd518832096..26fc9b5f1b6c 100644 --- a/mm/swap.c +++ b/mm/swap.c @@ -29,6 +29,7 @@ #include #include #include +#include #include #include #include @@ -743,7 +744,7 @@ void release_pages(struct page **pages, int nr) flags); locked_pgdat = NULL; } - put_zone_device_private_or_public_page(page); + put_devmap_managed_page(page); continue; }