diff options
author | Dan Williams <dan.j.williams@intel.com> | 2018-05-16 21:46:08 +0300 |
---|---|---|
committer | Dan Williams <dan.j.williams@intel.com> | 2018-05-22 16:59:39 +0300 |
commit | e7638488434415aa478e78435cac8f0365737638 (patch) | |
tree | 7ce50f0ed69889aa44cb0124451cf7a56b34eba6 /include | |
parent | 5981690ddb8f72f9546a2d017a914cf56095fc1f (diff) | |
download | linux-e7638488434415aa478e78435cac8f0365737638.tar.xz |
mm: introduce MEMORY_DEVICE_FS_DAX and CONFIG_DEV_PAGEMAP_OPS
In preparation for fixing dax-dma-vs-unmap issues, filesystems need to
be able to rely on the fact that they will get wakeups on dev_pagemap
page-idle events. Introduce MEMORY_DEVICE_FS_DAX and
generic_dax_page_free() as common indicator / infrastructure for dax
filesytems to require. With this change there are no users of the
MEMORY_DEVICE_HOST designation, so remove it.
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 <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Michal Hocko <mhocko@suse.com>
Reported-by: kbuild test robot <lkp@intel.com>
Reported-by: Thomas Meyer <thomas@m3y3r.de>
Reported-by: Dave Jiang <dave.jiang@intel.com>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'include')
-rw-r--r-- | include/linux/memremap.h | 36 | ||||
-rw-r--r-- | include/linux/mm.h | 71 |
2 files changed, 63 insertions, 44 deletions
diff --git a/include/linux/memremap.h b/include/linux/memremap.h index 7b4899c06f49..5ebfff65da4d 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 <linux/mm.h> #include <linux/ioport.h> #include <linux/percpu-refcount.h> @@ -30,13 +29,6 @@ struct vmem_altmap { * Specialize ZONE_DEVICE memory into multiple types each having differents * usage. * - * MEMORY_DEVICE_HOST: - * Persistent device memory (pmem): struct page might be allocated in different - * memory and architecture might want to perform special actions. It is similar - * to regular memory, in that the CPU can access it transparently. However, - * it is likely to have different bandwidth and latency than regular memory. - * See Documentation/nvdimm/nvdimm.txt for more information. - * * MEMORY_DEVICE_PRIVATE: * Device memory that is not directly addressable by the CPU: CPU can neither * read nor write private memory. In this case, we do still have struct pages @@ -53,11 +45,19 @@ struct vmem_altmap { * 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. + * + * MEMORY_DEVICE_FS_DAX: + * Host memory that has similar access semantics as System RAM i.e. DMA + * coherent and supports page pinning. In support of coordinating page + * pinning vs other operations MEMORY_DEVICE_FS_DAX arranges for a + * wakeup event whenever a page is unpinned and becomes idle. This + * wakeup is used to coordinate physical address space management (ex: + * fs truncate/hole punch) vs pinned pages (ex: device dma). */ enum memory_type { - MEMORY_DEVICE_HOST = 0, - MEMORY_DEVICE_PRIVATE, + MEMORY_DEVICE_PRIVATE = 1, MEMORY_DEVICE_PUBLIC, + MEMORY_DEVICE_FS_DAX, }; /* @@ -129,8 +129,6 @@ 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) @@ -161,20 +159,6 @@ 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); |