From patchwork Sun Dec 24 00:56:48 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Dan Williams X-Patchwork-Id: 10131755 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 1666E6037D for ; Sun, 24 Dec 2017 01:05:07 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0539628B11 for ; Sun, 24 Dec 2017 01:05:07 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id EC3EF28F78; Sun, 24 Dec 2017 01:05:06 +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 3132528B11 for ; Sun, 24 Dec 2017 01:05:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756799AbdLXBFE (ORCPT ); Sat, 23 Dec 2017 20:05:04 -0500 Received: from mga06.intel.com ([134.134.136.31]:17566 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756541AbdLXBFD (ORCPT ); Sat, 23 Dec 2017 20:05:03 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by orsmga104.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 23 Dec 2017 17:05:02 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.45,448,1508828400"; d="scan'208";a="186661205" Received: from dwillia2-desk3.jf.intel.com (HELO dwillia2-desk3.amr.corp.intel.com) ([10.54.39.16]) by orsmga005.jf.intel.com with ESMTP; 23 Dec 2017 17:05:02 -0800 Subject: [PATCH v4 09/18] mm, dax: enable filesystems to trigger dev_pagemap ->page_free callbacks From: Dan Williams To: akpm@linux-foundation.org Cc: Michal Hocko , jack@suse.cz, linux-nvdimm@lists.01.org, linux-xfs@vger.kernel.org, =?utf-8?b?SsOpcsO0bWU=?= Glisse , linux-fsdevel@vger.kernel.org, ross.zwisler@linux.intel.com, hch@lst.de Date: Sat, 23 Dec 2017 16:56:48 -0800 Message-ID: <151407700867.38751.6057494992833550623.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <151407695916.38751.2866053440557472361.stgit@dwillia2-desk3.amr.corp.intel.com> References: <151407695916.38751.2866053440557472361.stgit@dwillia2-desk3.amr.corp.intel.com> User-Agent: StGit/0.17.1-9-g687f 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 In order to resolve collisions between filesystem operations and DMA to DAX mapped pages we need a callback when DMA completes. With a callback we can hold off filesystem operations while DMA is in-flight and then resume those operations when the last put_page() occurs on a DMA page. Recall that the 'struct page' entries for DAX memory are created with devm_memremap_pages(). That routine arranges for the pages to be allocated, but never onlined, so a DAX page is DMA-idle when its reference count reaches one. Also recall that the HMM sub-system added infrastructure to trap the page-idle (2-to-1 reference count) transition of the pages allocated by devm_memremap_pages() and trigger a callback via the 'struct dev_pagemap' associated with the page range. Whereas the HMM callbacks are going to a device driver to manage bounce pages in device-memory in the filesystem-dax case we will call back to filesystem specified callback. Since the callback is not known at devm_memremap_pages() time we arrange for the filesystem to install it at mount time. No functional changes are expected as this only registers a nop handler for the ->page_free() event for device-mapped pages. Cc: Christoph Hellwig Cc: Michal Hocko Cc: "Jérôme Glisse" Signed-off-by: Dan Williams Reviewed-by: Christoph Hellwig --- drivers/dax/super.c | 79 ++++++++++++++++++++++++++++++++++++++++------ drivers/nvdimm/pmem.c | 3 +- fs/ext2/super.c | 6 ++- fs/ext4/super.c | 6 ++- fs/xfs/xfs_super.c | 20 ++++++------ include/linux/dax.h | 17 +++++----- include/linux/memremap.h | 8 +++++ 7 files changed, 103 insertions(+), 36 deletions(-) diff --git a/drivers/dax/super.c b/drivers/dax/super.c index 516124ae1ccf..e926e373a3a5 100644 --- a/drivers/dax/super.c +++ b/drivers/dax/super.c @@ -29,6 +29,7 @@ static struct vfsmount *dax_mnt; static DEFINE_IDA(dax_minor_ida); static struct kmem_cache *dax_cache __read_mostly; static struct super_block *dax_superblock __read_mostly; +static DEFINE_MUTEX(devmap_lock); #define DAX_HASH_SIZE (PAGE_SIZE / sizeof(struct hlist_head)) static struct hlist_head dax_host_list[DAX_HASH_SIZE]; @@ -62,16 +63,6 @@ int bdev_dax_pgoff(struct block_device *bdev, sector_t sector, size_t size, } EXPORT_SYMBOL(bdev_dax_pgoff); -#if IS_ENABLED(CONFIG_FS_DAX) -struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev) -{ - if (!blk_queue_dax(bdev->bd_queue)) - return NULL; - return fs_dax_get_by_host(bdev->bd_disk->disk_name); -} -EXPORT_SYMBOL_GPL(fs_dax_get_by_bdev); -#endif - /** * __bdev_dax_supported() - Check if the device supports dax for filesystem * @sb: The superblock of the device @@ -169,9 +160,66 @@ struct dax_device { const char *host; void *private; unsigned long flags; + struct dev_pagemap *pgmap; const struct dax_operations *ops; }; +#if IS_ENABLED(CONFIG_FS_DAX) +static void generic_dax_pagefree(struct page *page, void *data) +{ + /* TODO: wakeup page-idle waiters */ +} + +struct dax_device *fs_dax_claim_bdev(struct block_device *bdev, void *owner) +{ + struct dax_device *dax_dev; + struct dev_pagemap *pgmap; + + if (!blk_queue_dax(bdev->bd_queue)) + return NULL; + dax_dev = fs_dax_get_by_host(bdev->bd_disk->disk_name); + if (!dax_dev->pgmap) + return dax_dev; + pgmap = dax_dev->pgmap; + + mutex_lock(&devmap_lock); + if ((pgmap->data && pgmap->data != owner) || pgmap->page_free + || pgmap->page_fault + || pgmap->type != MEMORY_DEVICE_HOST) { + put_dax(dax_dev); + mutex_unlock(&devmap_lock); + return NULL; + } + + pgmap->type = MEMORY_DEVICE_FS_DAX; + pgmap->page_free = generic_dax_pagefree; + pgmap->data = owner; + mutex_unlock(&devmap_lock); + + return dax_dev; +} +EXPORT_SYMBOL_GPL(fs_dax_claim_bdev); + +void fs_dax_release(struct dax_device *dax_dev, void *owner) +{ + struct dev_pagemap *pgmap = dax_dev ? dax_dev->pgmap : NULL; + + put_dax(dax_dev); + if (!pgmap) + return; + if (!pgmap->data) + return; + + mutex_lock(&devmap_lock); + WARN_ON(pgmap->data != owner); + pgmap->type = MEMORY_DEVICE_HOST; + pgmap->page_free = NULL; + pgmap->data = NULL; + mutex_unlock(&devmap_lock); +} +EXPORT_SYMBOL_GPL(fs_dax_release); +#endif + static ssize_t write_cache_show(struct device *dev, struct device_attribute *attr, char *buf) { @@ -505,6 +553,17 @@ struct dax_device *alloc_dax(void *private, const char *__host, } EXPORT_SYMBOL_GPL(alloc_dax); +struct dax_device *alloc_dax_devmap(void *private, const char *host, + const struct dax_operations *ops, struct dev_pagemap *pgmap) +{ + struct dax_device *dax_dev = alloc_dax(private, host, ops); + + if (dax_dev) + dax_dev->pgmap = pgmap; + return dax_dev; +} +EXPORT_SYMBOL_GPL(alloc_dax_devmap); + void put_dax(struct dax_device *dax_dev) { if (!dax_dev) diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c index cf074b1ce219..bbe3044c1b26 100644 --- a/drivers/nvdimm/pmem.c +++ b/drivers/nvdimm/pmem.c @@ -407,7 +407,8 @@ static int pmem_attach_disk(struct device *dev, nvdimm_badblocks_populate(nd_region, &pmem->bb, &bb_res); disk->bb = &pmem->bb; - dax_dev = alloc_dax(pmem, disk->disk_name, &pmem_dax_ops); + dax_dev = alloc_dax_devmap(pmem, disk->disk_name, &pmem_dax_ops, + &pmem->pgmap); if (!dax_dev) { put_disk(disk); return -ENOMEM; diff --git a/fs/ext2/super.c b/fs/ext2/super.c index 38f9222606ee..b0d6d9954945 100644 --- a/fs/ext2/super.c +++ b/fs/ext2/super.c @@ -171,7 +171,7 @@ static void ext2_put_super (struct super_block * sb) brelse (sbi->s_sbh); sb->s_fs_info = NULL; kfree(sbi->s_blockgroup_lock); - fs_put_dax(sbi->s_daxdev); + fs_dax_release(sbi->s_daxdev, sb); kfree(sbi); } @@ -814,7 +814,7 @@ static unsigned long descriptor_loc(struct super_block *sb, static int ext2_fill_super(struct super_block *sb, void *data, int silent) { - struct dax_device *dax_dev = fs_dax_get_by_bdev(sb->s_bdev); + struct dax_device *dax_dev = fs_dax_claim_bdev(sb->s_bdev, sb); struct buffer_head * bh; struct ext2_sb_info * sbi; struct ext2_super_block * es; @@ -1210,7 +1210,7 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent) kfree(sbi->s_blockgroup_lock); kfree(sbi); failed: - fs_put_dax(dax_dev); + fs_dax_release(dax_dev, sb); return ret; } diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 18873ea89e08..238cad596733 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -950,7 +950,7 @@ static void ext4_put_super(struct super_block *sb) if (sbi->s_chksum_driver) crypto_free_shash(sbi->s_chksum_driver); kfree(sbi->s_blockgroup_lock); - fs_put_dax(sbi->s_daxdev); + fs_dax_release(sbi->s_daxdev, sb); kfree(sbi); } @@ -3396,7 +3396,7 @@ static void ext4_set_resv_clusters(struct super_block *sb) static int ext4_fill_super(struct super_block *sb, void *data, int silent) { - struct dax_device *dax_dev = fs_dax_get_by_bdev(sb->s_bdev); + struct dax_device *dax_dev = fs_dax_claim_bdev(sb->s_bdev, sb); char *orig_data = kstrdup(data, GFP_KERNEL); struct buffer_head *bh; struct ext4_super_block *es = NULL; @@ -4406,7 +4406,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) out_free_base: kfree(sbi); kfree(orig_data); - fs_put_dax(dax_dev); + fs_dax_release(dax_dev, sb); return err ? err : ret; } diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c index 5122d3021117..8ff821f3bcfb 100644 --- a/fs/xfs/xfs_super.c +++ b/fs/xfs/xfs_super.c @@ -722,7 +722,7 @@ xfs_close_devices( xfs_free_buftarg(mp, mp->m_logdev_targp); xfs_blkdev_put(logdev); - fs_put_dax(dax_logdev); + fs_dax_release(dax_logdev, mp); } if (mp->m_rtdev_targp) { struct block_device *rtdev = mp->m_rtdev_targp->bt_bdev; @@ -730,10 +730,10 @@ xfs_close_devices( xfs_free_buftarg(mp, mp->m_rtdev_targp); xfs_blkdev_put(rtdev); - fs_put_dax(dax_rtdev); + fs_dax_release(dax_rtdev, mp); } xfs_free_buftarg(mp, mp->m_ddev_targp); - fs_put_dax(dax_ddev); + fs_dax_release(dax_ddev, mp); } /* @@ -751,9 +751,9 @@ xfs_open_devices( struct xfs_mount *mp) { struct block_device *ddev = mp->m_super->s_bdev; - struct dax_device *dax_ddev = fs_dax_get_by_bdev(ddev); - struct dax_device *dax_logdev = NULL, *dax_rtdev = NULL; + struct dax_device *dax_ddev = fs_dax_claim_bdev(ddev, mp); struct block_device *logdev = NULL, *rtdev = NULL; + struct dax_device *dax_logdev = NULL, *dax_rtdev = NULL; int error; /* @@ -763,7 +763,7 @@ xfs_open_devices( error = xfs_blkdev_get(mp, mp->m_logname, &logdev); if (error) goto out; - dax_logdev = fs_dax_get_by_bdev(logdev); + dax_logdev = fs_dax_claim_bdev(logdev, mp); } if (mp->m_rtname) { @@ -777,7 +777,7 @@ xfs_open_devices( error = -EINVAL; goto out_close_rtdev; } - dax_rtdev = fs_dax_get_by_bdev(rtdev); + dax_rtdev = fs_dax_claim_bdev(rtdev, mp); } /* @@ -811,14 +811,14 @@ xfs_open_devices( xfs_free_buftarg(mp, mp->m_ddev_targp); out_close_rtdev: xfs_blkdev_put(rtdev); - fs_put_dax(dax_rtdev); + fs_dax_release(dax_rtdev, mp); out_close_logdev: if (logdev && logdev != ddev) { xfs_blkdev_put(logdev); - fs_put_dax(dax_logdev); + fs_dax_release(dax_logdev, mp); } out: - fs_put_dax(dax_ddev); + fs_dax_release(dax_ddev, mp); return error; } diff --git a/include/linux/dax.h b/include/linux/dax.h index 5258346c558c..1c6ed44fe9fc 100644 --- a/include/linux/dax.h +++ b/include/linux/dax.h @@ -51,12 +51,8 @@ static inline struct dax_device *fs_dax_get_by_host(const char *host) return dax_get_by_host(host); } -static inline void fs_put_dax(struct dax_device *dax_dev) -{ - put_dax(dax_dev); -} - -struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev); +struct dax_device *fs_dax_claim_bdev(struct block_device *bdev, void *owner); +void fs_dax_release(struct dax_device *dax_dev, void *owner); #else static inline int bdev_dax_supported(struct super_block *sb, int blocksize) { @@ -68,13 +64,14 @@ static inline struct dax_device *fs_dax_get_by_host(const char *host) return NULL; } -static inline void fs_put_dax(struct dax_device *dax_dev) +static inline struct dax_device *fs_dax_claim_bdev(struct block_device *bdev, + void *owner) { + return NULL; } -static inline struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev) +static inline void fs_dax_release(struct dax_device *dax_dev, void *owner) { - return NULL; } #endif @@ -82,6 +79,8 @@ int dax_read_lock(void); void dax_read_unlock(int id); struct dax_device *alloc_dax(void *private, const char *host, const struct dax_operations *ops); +struct dax_device *alloc_dax_devmap(void *private, const char *host, + const struct dax_operations *ops, struct dev_pagemap *pgmap); bool dax_alive(struct dax_device *dax_dev); void kill_dax(struct dax_device *dax_dev); void *dax_get_private(struct dax_device *dax_dev); diff --git a/include/linux/memremap.h b/include/linux/memremap.h index 7b4899c06f49..02d6d042ee7f 100644 --- a/include/linux/memremap.h +++ b/include/linux/memremap.h @@ -53,11 +53,19 @@ 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: + * When MEMORY_DEVICE_HOST memory is represented by a device that can + * host a filesystem, for example /dev/pmem0, that filesystem can + * register for a callback when a page is idled. For the filesystem-dax + * case page idle callbacks are used to coordinate DMA vs + * hole-punch/truncate. */ enum memory_type { MEMORY_DEVICE_HOST = 0, MEMORY_DEVICE_PRIVATE, MEMORY_DEVICE_PUBLIC, + MEMORY_DEVICE_FS_DAX, }; /*