From patchwork Thu Mar 15 15:52:12 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Dan Williams X-Patchwork-Id: 10285083 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 3F9C4602C2 for ; Thu, 15 Mar 2018 16:09:10 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2DC1B2893C for ; Thu, 15 Mar 2018 16:09:10 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 2041128B44; Thu, 15 Mar 2018 16:09:10 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3EE6528AFB for ; Thu, 15 Mar 2018 16:09:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751951AbeCOQIx (ORCPT ); Thu, 15 Mar 2018 12:08:53 -0400 Received: from mga11.intel.com ([192.55.52.93]:38312 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751475AbeCOQIv (ORCPT ); Thu, 15 Mar 2018 12:08:51 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga102.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 15 Mar 2018 09:01:18 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.48,311,1517904000"; d="scan'208";a="24809282" Received: from dwillia2-desk3.jf.intel.com (HELO dwillia2-desk3.amr.corp.intel.com) ([10.54.39.16]) by fmsmga008.fm.intel.com with ESMTP; 15 Mar 2018 09:01:17 -0700 Subject: [PATCH v6 09/15] mm, dev_pagemap: introduce CONFIG_DEV_PAGEMAP_OPS From: Dan Williams To: linux-nvdimm@lists.01.org Cc: Michal Hocko , =?utf-8?b?SsOpcsO0bWU=?= Glisse , david@fromorbit.com, hch@lst.de, linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, jack@suse.cz, ross.zwisler@linux.intel.com, hch@lst.de, linux-kernel@vger.kernel.org Date: Thu, 15 Mar 2018 08:52:12 -0700 Message-ID: <152112913205.24669.12417777615718867473.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <152112908134.24669.10222746224538377035.stgit@dwillia2-desk3.amr.corp.intel.com> References: <152112908134.24669.10222746224538377035.stgit@dwillia2-desk3.amr.corp.intel.com> User-Agent: StGit/0.18-2-gc94f MIME-Version: 1.0 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 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. Cc: Michal Hocko Reviewed-by: "Jérôme Glisse" Signed-off-by: Dan Williams --- drivers/dax/super.c | 2 ++ fs/Kconfig | 1 + include/linux/memremap.h | 20 ++------------- include/linux/mm.h | 61 ++++++++++++++++++++++++++++++++-------------- kernel/memremap.c | 30 ++++++++++++++++++++--- mm/Kconfig | 5 ++++ mm/hmm.c | 13 ++-------- mm/swap.c | 3 ++ 8 files changed, 84 insertions(+), 51 deletions(-) diff --git a/drivers/dax/super.c b/drivers/dax/super.c index ecefe9f7eb60..619b1ed6434c 100644 --- a/drivers/dax/super.c +++ b/drivers/dax/super.c @@ -191,6 +191,7 @@ struct dax_device *fs_dax_claim_bdev(struct block_device *bdev, void *owner) return NULL; } + dev_pagemap_get_ops(); pgmap->type = MEMORY_DEVICE_FS_DAX; pgmap->page_free = generic_dax_pagefree; pgmap->data = owner; @@ -215,6 +216,7 @@ 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); } EXPORT_SYMBOL_GPL(fs_dax_release); diff --git a/fs/Kconfig b/fs/Kconfig index bc821a86d965..1f0832bbc32f 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 select FS_IOMAP select DAX help diff --git a/include/linux/memremap.h b/include/linux/memremap.h index 02d6d042ee7f..9faf25d6abef 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 @@ -130,6 +129,9 @@ struct dev_pagemap { enum memory_type type; }; +void dev_pagemap_get_ops(void); +void dev_pagemap_put_ops(void); + #ifdef CONFIG_ZONE_DEVICE void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap); struct dev_pagemap *get_dev_pagemap(unsigned long pfn, @@ -137,8 +139,6 @@ 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 +169,6 @@ 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 ad06d42adb1a..088c76bce360 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -812,27 +812,55 @@ 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 __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; } -#define IS_HMM_ENABLED 0 + static inline bool is_device_private_page(const struct page *page) { - return false; + 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 /* CONFIG_DEV_PAGEMAP_OPS */ +static inline bool put_devmap_managed_page(struct page *page) +{ return false; } -#endif /* CONFIG_DEVICE_PRIVATE || CONFIG_DEVICE_PUBLIC */ +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_DEV_PAGEMAP_OPS */ static inline void get_page(struct page *page) { @@ -850,16 +878,13 @@ 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 4dd4274cabe2..72d0bb6fc47d 100644 --- a/kernel/memremap.c +++ b/kernel/memremap.c @@ -476,8 +476,30 @@ struct dev_pagemap *get_dev_pagemap(unsigned long pfn, } #endif /* CONFIG_ZONE_DEVICE */ -#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); @@ -497,5 +519,5 @@ 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 c782e8fb7235..dc32828984a3 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -700,6 +700,9 @@ config ARCH_HAS_HMM config MIGRATE_VMA_HELPER bool +config DEV_PAGEMAP_OPS + bool + config HMM bool select MIGRATE_VMA_HELPER @@ -720,6 +723,7 @@ 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 @@ -730,6 +734,7 @@ 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 320545b98ff5..4aa554e76d06 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; @@ -996,7 +987,7 @@ 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)); @@ -1090,7 +1081,7 @@ 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 0f17330dd0e5..eed846cfc8b8 100644 --- a/mm/swap.c +++ b/mm/swap.c @@ -29,6 +29,7 @@ #include #include #include +#include #include #include #include @@ -744,7 +745,7 @@ 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; }