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* device-dax: add memory via add_memory_driver_managed()David Hildenbrand2020-06-052-2/+27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, when adding memory, we create entries in /sys/firmware/memmap/ as "System RAM". This will lead to kexec-tools to add that memory to the fixed-up initial memmap for a kexec kernel (loaded via kexec_load()). The memory will be considered initial System RAM by the kexec'd kernel and can no longer be reconfigured. This is not what happens during a real reboot. Let's add our memory via add_memory_driver_managed() now, so we won't create entries in /sys/firmware/memmap/ and indicate the memory as "System RAM (kmem)" in /proc/iomem. This allows everybody (especially kexec-tools) to identify that this memory is special and has to be treated differently than ordinary (hotplugged) System RAM. Before configuring the namespace: [root@localhost ~]# cat /proc/iomem ... 140000000-33fffffff : Persistent Memory 140000000-33fffffff : namespace0.0 3280000000-32ffffffff : PCI Bus 0000:00 After configuring the namespace: [root@localhost ~]# cat /proc/iomem ... 140000000-33fffffff : Persistent Memory 140000000-1481fffff : namespace0.0 148200000-33fffffff : dax0.0 3280000000-32ffffffff : PCI Bus 0000:00 After loading kmem before this change: [root@localhost ~]# cat /proc/iomem ... 140000000-33fffffff : Persistent Memory 140000000-1481fffff : namespace0.0 150000000-33fffffff : dax0.0 150000000-33fffffff : System RAM 3280000000-32ffffffff : PCI Bus 0000:00 After loading kmem after this change: [root@localhost ~]# cat /proc/iomem ... 140000000-33fffffff : Persistent Memory 140000000-1481fffff : namespace0.0 150000000-33fffffff : dax0.0 150000000-33fffffff : System RAM (kmem) 3280000000-32ffffffff : PCI Bus 0000:00 After a proper reboot: [root@localhost ~]# cat /proc/iomem ... 140000000-33fffffff : Persistent Memory 140000000-1481fffff : namespace0.0 148200000-33fffffff : dax0.0 3280000000-32ffffffff : PCI Bus 0000:00 Within the kexec kernel before this change: [root@localhost ~]# cat /proc/iomem ... 140000000-33fffffff : Persistent Memory 140000000-1481fffff : namespace0.0 150000000-33fffffff : System RAM 3280000000-32ffffffff : PCI Bus 0000:00 Within the kexec kernel after this change: [root@localhost ~]# cat /proc/iomem ... 140000000-33fffffff : Persistent Memory 140000000-1481fffff : namespace0.0 148200000-33fffffff : dax0.0 3280000000-32ffffffff : PCI Bus 0000:00 /sys/firmware/memmap/ before this change: 0000000000000000-000000000009fc00 (System RAM) 000000000009fc00-00000000000a0000 (Reserved) 00000000000f0000-0000000000100000 (Reserved) 0000000000100000-00000000bffdf000 (System RAM) 00000000bffdf000-00000000c0000000 (Reserved) 00000000feffc000-00000000ff000000 (Reserved) 00000000fffc0000-0000000100000000 (Reserved) 0000000100000000-0000000140000000 (System RAM) 0000000150000000-0000000340000000 (System RAM) /sys/firmware/memmap/ after a proper reboot: 0000000000000000-000000000009fc00 (System RAM) 000000000009fc00-00000000000a0000 (Reserved) 00000000000f0000-0000000000100000 (Reserved) 0000000000100000-00000000bffdf000 (System RAM) 00000000bffdf000-00000000c0000000 (Reserved) 00000000feffc000-00000000ff000000 (Reserved) 00000000fffc0000-0000000100000000 (Reserved) 0000000100000000-0000000140000000 (System RAM) /sys/firmware/memmap/ after this change: 0000000000000000-000000000009fc00 (System RAM) 000000000009fc00-00000000000a0000 (Reserved) 00000000000f0000-0000000000100000 (Reserved) 0000000000100000-00000000bffdf000 (System RAM) 00000000bffdf000-00000000c0000000 (Reserved) 00000000feffc000-00000000ff000000 (Reserved) 00000000fffc0000-0000000100000000 (Reserved) 0000000100000000-0000000140000000 (System RAM) kexec-tools already seem to basically ignore any System RAM that's not on top level when searching for areas to place kexec images - but also for determining crash areas to dump via kdump. Changing the resource name won't have an impact. Handle unloading of the driver after memory hotremove failed properly, by duplicating the string if necessary. Signed-off-by: David Hildenbrand <david@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Baoquan He <bhe@redhat.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Eric Biederman <ebiederm@xmission.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Dan Williams <dan.j.williams@intel.com> Link: http://lkml.kernel.org/r/20200508084217.9160-5-david@redhat.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* vfs: track per-sb writeback errors and report them to syncfsJeff Layton2020-06-021-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Patch series "vfs: have syncfs() return error when there are writeback errors", v6. Currently, syncfs does not return errors when one of the inodes fails to be written back. It will return errors based on the legacy AS_EIO and AS_ENOSPC flags when syncing out the block device fails, but that's not particularly helpful for filesystems that aren't backed by a blockdev. It's also possible for a stray sync to lose those errors. The basic idea in this set is to track writeback errors at the superblock level, so that we can quickly and easily check whether something bad happened without having to fsync each file individually. syncfs is then changed to reliably report writeback errors after they occur, much in the same fashion as fsync does now. This patch (of 2): Usually we suggest that applications call fsync when they want to ensure that all data written to the file has made it to the backing store, but that can be inefficient when there are a lot of open files. Calling syncfs on the filesystem can be more efficient in some situations, but the error reporting doesn't currently work the way most people expect. If a single inode on a filesystem reports a writeback error, syncfs won't necessarily return an error. syncfs only returns an error if __sync_blockdev fails, and on some filesystems that's a no-op. It would be better if syncfs reported an error if there were any writeback failures. Then applications could call syncfs to see if there are any errors on any open files, and could then call fsync on all of the other descriptors to figure out which one failed. This patch adds a new errseq_t to struct super_block, and has mapping_set_error also record writeback errors there. To report those errors, we also need to keep an errseq_t in struct file to act as a cursor. This patch adds a dedicated field for that purpose, which slots nicely into 4 bytes of padding at the end of struct file on x86_64. An earlier version of this patch used an O_PATH file descriptor to cue the kernel that the open file should track the superblock error and not the inode's writeback error. I think that API is just too weird though. This is simpler and should make syncfs error reporting "just work" even if someone is multiplexing fsync and syncfs on the same fds. Signed-off-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Andres Freund <andres@anarazel.de> Cc: Matthew Wilcox <willy@infradead.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@infradead.org> Cc: Dave Chinner <david@fromorbit.com> Cc: David Howells <dhowells@redhat.com> Link: http://lkml.kernel.org/r/20200428135155.19223-1-jlayton@kernel.org Link: http://lkml.kernel.org/r/20200428135155.19223-2-jlayton@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* device-dax: don't leak kernel memory to user space after unloading kmemDavid Hildenbrand2020-05-231-3/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Assume we have kmem configured and loaded: [root@localhost ~]# cat /proc/iomem ... 140000000-33fffffff : Persistent Memory$ 140000000-1481fffff : namespace0.0 150000000-33fffffff : dax0.0 150000000-33fffffff : System RAM Assume we try to unload kmem. This force-unloading will work, even if memory cannot get removed from the system. [root@localhost ~]# rmmod kmem [ 86.380228] removing memory fails, because memory [0x0000000150000000-0x0000000157ffffff] is onlined ... [ 86.431225] kmem dax0.0: DAX region [mem 0x150000000-0x33fffffff] cannot be hotremoved until the next reboot Now, we can reconfigure the namespace: [root@localhost ~]# ndctl create-namespace --force --reconfig=namespace0.0 --mode=devdax [ 131.409351] nd_pmem namespace0.0: could not reserve region [mem 0x140000000-0x33fffffff]dax [ 131.410147] nd_pmem: probe of namespace0.0 failed with error -16namespace0.0 --mode=devdax ... This fails as expected due to the busy memory resource, and the memory cannot be used. However, the dax0.0 device is removed, and along its name. The name of the memory resource now points at freed memory (name of the device): [root@localhost ~]# cat /proc/iomem ... 140000000-33fffffff : Persistent Memory 140000000-1481fffff : namespace0.0 150000000-33fffffff : �_�^7_��/_��wR��WQ���^��� ... 150000000-33fffffff : System RAM We have to make sure to duplicate the string. While at it, remove the superfluous setting of the name and fixup a stale comment. Fixes: 9f960da72b25 ("device-dax: "Hotremove" persistent memory that is used like normal RAM") Signed-off-by: David Hildenbrand <david@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Vishal Verma <vishal.l.verma@intel.com> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: <stable@vger.kernel.org> [5.3] Link: http://lkml.kernel.org/r/20200508084217.9160-2-david@redhat.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* dax: Move mandatory ->zero_page_range() check in alloc_dax()Vivek Goyal2020-04-032-6/+12
| | | | | | | | | | | | | | | zero_page_range() dax operation is mandatory for dax devices. Right now that check happens in dax_zero_page_range() function. Dan thinks that's too late and its better to do the check earlier in alloc_dax(). I also modified alloc_dax() to return pointer with error code in it in case of failure. Right now it returns NULL and caller assumes failure happened due to -ENOMEM. But with this ->zero_page_range() check, I need to return -EINVAL instead. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Link: https://lore.kernel.org/r/20200401161125.GB9398@redhat.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* dax, pmem: Add a dax operation zero_page_rangeVivek Goyal2020-04-031-0/+20
| | | | | | | | | | | | | | | | | | | Add a dax operation zero_page_range, to zero a page. This will also clear any known poison in the page being zeroed. As of now, zeroing of one page is allowed in a single call. There are no callers which are trying to zero more than a page in a single call. Once we grow the callers which zero more than a page in single call, we can add that support. Primary reason for not doing that yet is that this will add little complexity in dm implementation where a range might be spanning multiple underlying targets and one will have to split the range into multiple sub ranges and call zero_page_range() on individual targets. Suggested-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Reviewed-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Link: https://lore.kernel.org/r/20200228163456.1587-3-vgoyal@redhat.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* dax: Get rid of fs_dax_get_by_host() helperVivek Goyal2020-01-161-1/+1
| | | | | | | | | | | | | | | Looks like nobody is using fs_dax_get_by_host() except fs_dax_get_by_bdev() and it can easily use dax_get_by_host() instead. IIUC, fs_dax_get_by_host() was only introduced so that one could compile with CONFIG_FS_DAX=n and CONFIG_DAX=m. fs_dax_get_by_bdev() achieves the same purpose and hence it looks like fs_dax_get_by_host() is not needed anymore. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20200106181117.GA16248@redhat.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* Merge tag 'libnvdimm-for-5.5' of ↵Linus Torvalds2019-12-022-8/+20
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm Pull libnvdimm updates from Dan Williams: "The highlight this cycle is continuing integration fixes for PowerPC and some resulting optimizations. Summary: - Updates to better support vmalloc space restrictions on PowerPC platforms. - Cleanups to move common sysfs attributes to core 'struct device_type' objects. - Export the 'target_node' attribute (the effective numa node if pmem is marked online) for regions and namespaces. - Miscellaneous fixups and optimizations" * tag 'libnvdimm-for-5.5' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: (21 commits) MAINTAINERS: Remove Keith from NVDIMM maintainers libnvdimm: Export the target_node attribute for regions and namespaces dax: Add numa_node to the default device-dax attributes libnvdimm: Simplify root read-only definition for the 'resource' attribute dax: Simplify root read-only definition for the 'resource' attribute dax: Create a dax device_type libnvdimm: Move nvdimm_bus_attribute_group to device_type libnvdimm: Move nvdimm_attribute_group to device_type libnvdimm: Move nd_mapping_attribute_group to device_type libnvdimm: Move nd_region_attribute_group to device_type libnvdimm: Move nd_numa_attribute_group to device_type libnvdimm: Move nd_device_attribute_group to device_type libnvdimm: Move region attribute group definition libnvdimm: Move attribute groups to device type libnvdimm: Remove prototypes for nonexistent functions libnvdimm/btt: fix variable 'rc' set but not used libnvdimm/pmem: Delete include of nd-core.h libnvdimm/namespace: Differentiate between probe mapping and runtime mapping libnvdimm/pfn_dev: Don't clear device memmap area during generic namespace probe libnvdimm: Trivial comment fix ...
| * dax: Add numa_node to the default device-dax attributesDan Williams2019-11-191-0/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | It is confusing that device-dax instances publish a 'target_node' attribute, but not a 'numa_node'. The 'numa_node' information is available elsewhere in the sysfs device hierarchy, but it is not obvious and not reliable from one device-dax instance-type (e.g. child devices of nvdimm namespaces) to the next (e.g. 'hmem' devices defined by EFI Specific Purpose Memory and the ACPI HMAT). Cc: Ira Weiny <ira.weiny@intel.com> Cc: Vishal Verma <vishal.l.verma@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Link: https://lore.kernel.org/r/157309906102.1582359.4262088001244476001.stgit@dwillia2-desk3.amr.corp.intel.com
| * dax: Simplify root read-only definition for the 'resource' attributeDan Williams2019-11-191-3/+1
| | | | | | | | | | | | | | | | | | | | Rather than update the permission in ->is_visible() set the permission directly at declaration time. Cc: Ira Weiny <ira.weiny@intel.com> Cc: Vishal Verma <vishal.l.verma@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Link: https://lore.kernel.org/r/157309904959.1582359.7281180042781955506.stgit@dwillia2-desk3.amr.corp.intel.com
| * dax: Create a dax device_typeDan Williams2019-11-191-2/+6
| | | | | | | | | | | | | | | | | | | | Move the open coded release method and attribute groups to a 'struct device_type' instance. Cc: Ira Weiny <ira.weiny@intel.com> Cc: Vishal Verma <vishal.l.verma@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Link: https://lore.kernel.org/r/157309904365.1582359.5451327195246651379.stgit@dwillia2-desk3.amr.corp.intel.com
| * libnvdimm/namespace: Differentiate between probe mapping and runtime mappingAneesh Kumar K.V2019-11-151-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The nvdimm core currently maps the full namespace to an ioremap range while probing the namespace mode. This can result in probe failures on architectures that have limited ioremap space. For example, with a large btt namespace that consumes most of I/O remap range, depending on the sequence of namespace initialization, the user can find a pfn namespace initialization failure due to unavailable I/O remap space which nvdimm core uses for temporary mapping. nvdimm core can avoid this failure by only mapping the reserved info block area to check for pfn superblock type and map the full namespace resource only before using the namespace. Given that personalities like BTT can be layered on top of any namespace type create a generic form of devm_nsio_enable (devm_namespace_enable) and use it inside the per-personality attach routines. Now devm_namespace_enable() is always paired with disable unless the mapping is going to be used for long term runtime access. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Link: https://lore.kernel.org/r/20191017073308.32645-1-aneesh.kumar@linux.ibm.com [djbw: reworks to move devm_namespace_{en,dis}able into *attach helpers] Reported-by: kbuild test robot <lkp@intel.com> Link: https://lore.kernel.org/r/20191031105741.102793-2-aneesh.kumar@linux.ibm.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* | device-dax: Add a driver for "hmem" devicesDan Williams2019-11-073-5/+80
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Platform firmware like EFI/ACPI may publish "hmem" platform devices. Such a device is a performance differentiated memory range likely reserved for an application specific use case. The driver gives access to 100% of the capacity via a device-dax mmap instance by default. However, if over-subscription and other kernel memory management is desired the resulting dax device can be assigned to the core-mm via the kmem driver. This consumes "hmem" devices the producer of "hmem" devices is saved for a follow-on patch so that it can reference the new CONFIG_DEV_DAX_HMEM symbol to gate performing the enumeration work. Reported-by: kbuild test robot <lkp@intel.com> Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Acked-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* | dax: Fix alloc_dax_region() compile warningDan Williams2019-11-073-3/+3
|/ | | | | | | | | | | | | PFN flags are (unsigned long long), fix the alloc_dax_region() calling convention to fix warnings of the form: >> include/linux/pfn_t.h:18:17: warning: large integer implicitly truncated to unsigned type [-Woverflow] #define PFN_DEV (1ULL << (BITS_PER_LONG_LONG - 3)) Reported-by: kbuild test robot <lkp@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Acked-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* Merge branch 'work.mount0' of ↵Linus Torvalds2019-07-191-13/+10
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs mount updates from Al Viro: "The first part of mount updates. Convert filesystems to use the new mount API" * 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (63 commits) mnt_init(): call shmem_init() unconditionally constify ksys_mount() string arguments don't bother with registering rootfs init_rootfs(): don't bother with init_ramfs_fs() vfs: Convert smackfs to use the new mount API vfs: Convert selinuxfs to use the new mount API vfs: Convert securityfs to use the new mount API vfs: Convert apparmorfs to use the new mount API vfs: Convert openpromfs to use the new mount API vfs: Convert xenfs to use the new mount API vfs: Convert gadgetfs to use the new mount API vfs: Convert oprofilefs to use the new mount API vfs: Convert ibmasmfs to use the new mount API vfs: Convert qib_fs/ipathfs to use the new mount API vfs: Convert efivarfs to use the new mount API vfs: Convert configfs to use the new mount API vfs: Convert binfmt_misc to use the new mount API convenience helper: get_tree_single() convenience helper get_tree_nodev() vfs: Kill sget_userns() ...
| * vfs: Convert dax to use the new mount APIDavid Howells2019-05-261-6/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Convert the dax filesystem to the new internal mount API as the old one will be obsoleted and removed. This allows greater flexibility in communication of mount parameters between userspace, the VFS and the filesystem. See Documentation/filesystems/mount_api.txt for more information. Signed-off-by: David Howells <dhowells@redhat.com> cc: Dan Williams <dan.j.williams@intel.com> cc: Vishal Verma <vishal.l.verma@intel.com> cc: Keith Busch <keith.busch@intel.com> cc: Dave Jiang <dave.jiang@intel.com> cc: linux-nvdimm@lists.01.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * mount_pseudo(): drop 'name' argument, switch to d_make_root()Al Viro2019-05-251-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Once upon a time we used to set ->d_name of e.g. pipefs root so that d_path() on pipes would work. These days it's completely pointless - dentries of pipes are not even connected to pipefs root. However, mount_pseudo() had set the root dentry name (passed as the second argument) and callers kept inventing names to pass to it. Including those that didn't *have* any non-root dentries to start with... All of that had been pointless for about 8 years now; it's time to get rid of that cargo-culting... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * device-dax: Drop register_filesystem()Dan Williams2019-05-211-7/+0
| | | | | | | | | | | | | | | | | | | | | | | | The device-dax fs is only there to allocate a common inode for each device-node that refers to the same device by major:minor. It is otherwise not user mountable and need not be displayed in /proc/filesystems. Reported-by: Al Viro <viro@zeniv.linux.org.uk> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | Merge tag 'dax-for-5.3' of ↵Linus Torvalds2019-07-181-0/+19
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm Pull dax updates from Dan Williams: "The fruits of a bug hunt in the fsdax implementation with Willy and a small feature update for device-dax: - Fix a hang condition that started triggering after the Xarray conversion of fsdax in the v4.20 kernel. - Add a 'resource' (root-only physical base address) sysfs attribute to device-dax instances to correlate memory-blocks onlined via the kmem driver with a given device instance" * tag 'dax-for-5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: dax: Fix missed wakeup with PMD faults device-dax: Add a 'resource' attribute
| * | device-dax: Add a 'resource' attributeVishal Verma2019-06-211-0/+19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | device-dax based devices were missing a 'resource' attribute to indicate the physical address range contributed by the device in question. This information is desirable to userspace tooling that may want to use the dax device as system-ram, and wants to selectively hotplug and online the memory blocks associated with a given device. Without this, the tooling would have to parse /proc/iomem for the memory ranges contributed by dax devices, which can be a workaround, but it is far easier to provide this information in the sysfs hierarchy. Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Vishal Verma <vishal.l.verma@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* | | Merge tag 'libnvdimm-for-5.3' of ↵Linus Torvalds2019-07-182-2/+19
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm Pull libnvdimm updates from Dan Williams: "Primarily just the virtio_pmem driver: - virtio_pmem The new virtio_pmem facility introduces a paravirtualized persistent memory device that allows a guest VM to use DAX mechanisms to access a host-file with host-page-cache. It arranges for MAP_SYNC to be disabled and instead triggers a host fsync() when a 'write-cache flush' command is sent to the virtual disk device. - Miscellaneous small fixups" * tag 'libnvdimm-for-5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: virtio_pmem: fix sparse warning xfs: disable map_sync for async flush ext4: disable map_sync for async flush dax: check synchronous mapping is supported dm: enable synchronous dax libnvdimm: add dax_dev sync flag virtio-pmem: Add virtio pmem driver libnvdimm: nd_region flush callback support libnvdimm, namespace: Drop uuid_t implementation detail
| * | | libnvdimm: add dax_dev sync flagPankaj Gupta2019-07-062-2/+19
| |/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch adds 'DAXDEV_SYNC' flag which is set for nd_region doing synchronous flush. This later is used to disable MAP_SYNC functionality for ext4 & xfs filesystem for devices don't support synchronous flush. Signed-off-by: Pankaj Gupta <pagupta@redhat.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* | | device-dax: "Hotremove" persistent memory that is used like normal RAMPavel Tatashin2019-07-172-4/+39
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It is now allowed to use persistent memory like a regular RAM, but currently there is no way to remove this memory until machine is rebooted. This work expands the functionality to also allows hotremoving previously hotplugged persistent memory, and recover the device for use for other purposes. To hotremove persistent memory, the management software must first offline all memory blocks of dax region, and than unbind it from device-dax/kmem driver. So, operations should look like this: echo offline > /sys/devices/system/memory/memoryN/state ... echo dax0.0 > /sys/bus/dax/drivers/kmem/unbind Note: if unbind is done without offlining memory beforehand, it won't be possible to do dax0.0 hotremove, and dax's memory is going to be part of System RAM until reboot. Link: http://lkml.kernel.org/r/20190517215438.6487-4-pasha.tatashin@soleen.com Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com> Reviewed-by: David Hildenbrand <david@redhat.com> Cc: James Morris <jmorris@namei.org> Cc: Sasha Levin <sashal@kernel.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Keith Busch <keith.busch@intel.com> Cc: Vishal Verma <vishal.l.verma@intel.com> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Ross Zwisler <zwisler@kernel.org> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Huang Ying <ying.huang@intel.com> Cc: Fengguang Wu <fengguang.wu@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Yaowei Bai <baiyaowei@cmss.chinamobile.com> Cc: Takashi Iwai <tiwai@suse.de> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Dave Hansen <dave.hansen@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | device-dax: fix memory and resource leak if hotplug failsPavel Tatashin2019-07-171-1/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Patch series ""Hotremove" persistent memory", v6. Recently, adding a persistent memory to be used like a regular RAM was added to Linux. This work extends this functionality to also allow hot removing persistent memory. We (Microsoft) have an important use case for this functionality. The requirement is for physical machines with small amount of RAM (~8G) to be able to reboot in a very short period of time (<1s). Yet, there is a userland state that is expensive to recreate (~2G). The solution is to boot machines with 2G preserved for persistent memory. Copy the state, and hotadd the persistent memory so machine still has all 8G available for runtime. Before reboot, offline and hotremove device-dax 2G, copy the memory that is needed to be preserved to pmem0 device, and reboot. The series of operations look like this: 1. After boot restore /dev/pmem0 to ramdisk to be consumed by apps. and free ramdisk. 2. Convert raw pmem0 to devdax ndctl create-namespace --mode devdax --map mem -e namespace0.0 -f 3. Hotadd to System RAM echo dax0.0 > /sys/bus/dax/drivers/device_dax/unbind echo dax0.0 > /sys/bus/dax/drivers/kmem/new_id echo online_movable > /sys/devices/system/memoryXXX/state 4. Before reboot hotremove device-dax memory from System RAM echo offline > /sys/devices/system/memoryXXX/state echo dax0.0 > /sys/bus/dax/drivers/kmem/unbind 5. Create raw pmem0 device ndctl create-namespace --mode raw -e namespace0.0 -f 6. Copy the state that was stored by apps to ramdisk to pmem device 7. Do kexec reboot or reboot through firmware if firmware does not zero memory in pmem0 region (These machines have only regular volatile memory). So to have pmem0 device either memmap kernel parameter is used, or devices nodes in dtb are specified. This patch (of 3): When add_memory() fails, the resource and the memory should be freed. Link: http://lkml.kernel.org/r/20190517215438.6487-2-pasha.tatashin@soleen.com Fixes: c221c0b0308f ("device-dax: "Hotplug" persistent memory for use like normal RAM") Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com> Reviewed-by: Dave Hansen <dave.hansen@intel.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Borislav Petkov <bp@suse.de> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Dave Jiang <dave.jiang@intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: Fengguang Wu <fengguang.wu@intel.com> Cc: Huang Ying <ying.huang@intel.com> Cc: James Morris <jmorris@namei.org> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Keith Busch <keith.busch@intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Ross Zwisler <zwisler@kernel.org> Cc: Sasha Levin <sashal@kernel.org> Cc: Takashi Iwai <tiwai@suse.de> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Vishal Verma <vishal.l.verma@intel.com> Cc: Yaowei Bai <baiyaowei@cmss.chinamobile.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | device-dax: use the dev_pagemap internal refcountChristoph Hellwig2019-07-022-47/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The functionality is identical to the one currently open coded in device-dax. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ira Weiny <ira.weiny@intel.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Tested-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
* | | memremap: pass a struct dev_pagemap to ->kill and ->cleanupChristoph Hellwig2019-07-021-6/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Passing the actual typed structure leads to more understandable code vs just passing the ref member. Reported-by: Logan Gunthorpe <logang@deltatee.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Logan Gunthorpe <logang@deltatee.com> Reviewed-by: Jason Gunthorpe <jgg@mellanox.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Tested-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
* | | memremap: move dev_pagemap callbacks into a separate structureChristoph Hellwig2019-07-022-5/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The dev_pagemap is a growing too many callbacks. Move them into a separate ops structure so that they are not duplicated for multiple instances, and an attacker can't easily overwrite them. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Logan Gunthorpe <logang@deltatee.com> Reviewed-by: Jason Gunthorpe <jgg@mellanox.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Tested-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
* | | memremap: validate the pagemap type passed to devm_memremap_pagesChristoph Hellwig2019-07-021-0/+1
|/ / | | | | | | | | | | | | | | | | | | | | | | | | Most pgmap types are only supported when certain config options are enabled. Check for a type that is valid for the current configuration before setting up the pagemap. For this the usage of the 0 type for device dax gets replaced with an explicit MEMORY_DEVICE_DEVDAX type. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ira Weiny <ira.weiny@intel.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Tested-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
* | mm/devm_memremap_pages: fix final page put raceDan Williams2019-06-141-10/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Logan noticed that devm_memremap_pages_release() kills the percpu_ref drops all the page references that were acquired at init and then immediately proceeds to unplug, arch_remove_memory(), the backing pages for the pagemap. If for some reason device shutdown actually collides with a busy / elevated-ref-count page then arch_remove_memory() should be deferred until after that reference is dropped. As it stands the "wait for last page ref drop" happens *after* devm_memremap_pages_release() returns, which is obviously too late and can lead to crashes. Fix this situation by assigning the responsibility to wait for the percpu_ref to go idle to devm_memremap_pages() with a new ->cleanup() callback. Implement the new cleanup callback for all devm_memremap_pages() users: pmem, devdax, hmm, and p2pdma. Link: http://lkml.kernel.org/r/155727339156.292046.5432007428235387859.stgit@dwillia2-desk3.amr.corp.intel.com Fixes: 41e94a851304 ("add devm_memremap_pages") Signed-off-by: Dan Williams <dan.j.williams@intel.com> Reported-by: Logan Gunthorpe <logang@deltatee.com> Reviewed-by: Ira Weiny <ira.weiny@intel.com> Reviewed-by: Logan Gunthorpe <logang@deltatee.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: "Jérôme Glisse" <jglisse@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 295Thomas Gleixner2019-06-052-18/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of version 2 of the gnu general public license as published by the free software foundation this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 64 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Alexios Zavras <alexios.zavras@intel.com> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190529141901.894819585@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | Merge tag 'libnvdimm-fixes-5.2-rc2' of ↵Linus Torvalds2019-05-251-31/+57
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm Pull libnvdimm fixes from Dan Williams: - Fix a regression that disabled device-mapper dax support - Remove unnecessary hardened-user-copy overhead (>30%) for dax read(2)/write(2). - Fix some compilation warnings. * tag 'libnvdimm-fixes-5.2-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: libnvdimm/pmem: Bypass CONFIG_HARDENED_USERCOPY overhead dax: Arrange for dax_supported check to span multiple devices libnvdimm: Fix compilation warnings with W=1
| * | dax: Arrange for dax_supported check to span multiple devicesDan Williams2019-05-211-31/+57
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pankaj reports that starting with commit ad428cdb525a "dax: Check the end of the block-device capacity with dax_direct_access()" device-mapper no longer allows dax operation. This results from the stricter checks in __bdev_dax_supported() that validate that the start and end of a block-device map to the same 'pagemap' instance. Teach the dax-core and device-mapper to validate the 'pagemap' on a per-target basis. This is accomplished by refactoring the bdev_dax_supported() internals into generic_fsdax_supported() which takes a sector range to validate. Consequently generic_fsdax_supported() is suitable to be used in a device-mapper ->iterate_devices() callback. A new ->dax_supported() operation is added to allow composite devices to split and route upper-level bdev_dax_supported() requests. Fixes: ad428cdb525a ("dax: Check the end of the block-device...") Cc: <stable@vger.kernel.org> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Keith Busch <keith.busch@intel.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Vishal Verma <vishal.l.verma@intel.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Reviewed-by: Jan Kara <jack@suse.cz> Reported-by: Pankaj Gupta <pagupta@redhat.com> Reviewed-by: Pankaj Gupta <pagupta@redhat.com> Tested-by: Pankaj Gupta <pagupta@redhat.com> Tested-by: Vaibhav Jain <vaibhav@linux.ibm.com> Reviewed-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* / treewide: Add SPDX license identifier - Makefile/KconfigThomas Gleixner2019-05-212-0/+2
|/ | | | | | | | | | | | | | Add SPDX license identifiers to all Make/Kconfig files which: - Have no license information of any form These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Merge tag 'libnvdimm-fixes-5.2-rc1' of ↵Linus Torvalds2019-05-162-5/+4
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm Pull libnvdimm updates from Dan Williams: "Just a small collection of fixes this time around. The new virtio-pmem driver is nearly ready, but some last minute device-mapper acks and virtio questions made it prudent to await v5.3. Other major topics that were brewing on the linux-nvdimm mailing list like sub-section hotplug, and other devm_memremap_pages() reworks will go upstream through Andrew's tree. Summary: - Fix a long standing namespace label corruption scenario when re-provisioning capacity for a namespace. - Restore the ability of the dax_pmem module to be built-in. - Harden the build for the 'nfit_test' unit test modules so that the userspace test harness can ensure all required test modules are available" * tag 'libnvdimm-fixes-5.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: drivers/dax: Allow to include DEV_DAX_PMEM as builtin libnvdimm/namespace: Fix label tracking error tools/testing/nvdimm: add watermarks for dax_pmem* modules dax/pmem: Fix whitespace in dax_pmem
| * drivers/dax: Allow to include DEV_DAX_PMEM as builtinAneesh Kumar K.V2019-05-071-2/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | This move the dependency to DEV_DAX_PMEM_COMPAT such that only if DEV_DAX_PMEM is built as module we can allow the compat support. This allows to test the new code easily in a emulation setup where we often build things without module support. Cc: <stable@vger.kernel.org> Fixes: 730926c3b099 ("device-dax: Add /sys/class/dax backwards compatibility") Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
| * dax/pmem: Fix whitespace in dax_pmemVishal Verma2019-04-231-3/+3
| | | | | | | | | | | | | | | | | | | | A few lines were whitespace damaged, with spaces at the start instead of tabs. This was noticed while debugging an nfit_test failure, so fix them. Cc: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Vishal Verma <vishal.l.verma@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* | mm/huge_memory: fix vmf_insert_pfn_{pmd, pud}() crash, handle unaligned ↵Dan Williams2019-05-141-4/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | addresses Starting with c6f3c5ee40c1 ("mm/huge_memory.c: fix modifying of page protection by insert_pfn_pmd()") vmf_insert_pfn_pmd() internally calls pmdp_set_access_flags(). That helper enforces a pmd aligned @address argument via VM_BUG_ON() assertion. Update the implementation to take a 'struct vm_fault' argument directly and apply the address alignment fixup internally to fix crash signatures like: kernel BUG at arch/x86/mm/pgtable.c:515! invalid opcode: 0000 [#1] SMP NOPTI CPU: 51 PID: 43713 Comm: java Tainted: G OE 4.19.35 #1 [..] RIP: 0010:pmdp_set_access_flags+0x48/0x50 [..] Call Trace: vmf_insert_pfn_pmd+0x198/0x350 dax_iomap_fault+0xe82/0x1190 ext4_dax_huge_fault+0x103/0x1f0 ? __switch_to_asm+0x40/0x70 __handle_mm_fault+0x3f6/0x1370 ? __switch_to_asm+0x34/0x70 ? __switch_to_asm+0x40/0x70 handle_mm_fault+0xda/0x200 __do_page_fault+0x249/0x4f0 do_page_fault+0x32/0x110 ? page_fault+0x8/0x30 page_fault+0x1e/0x30 Link: http://lkml.kernel.org/r/155741946350.372037.11148198430068238140.stgit@dwillia2-desk3.amr.corp.intel.com Fixes: c6f3c5ee40c1 ("mm/huge_memory.c: fix modifying of page protection by insert_pfn_pmd()") Signed-off-by: Dan Williams <dan.j.williams@intel.com> Reported-by: Piotr Balcer <piotr.balcer@intel.com> Tested-by: Yan Ma <yan.ma@intel.com> Tested-by: Pankaj Gupta <pagupta@redhat.com> Reviewed-by: Matthew Wilcox <willy@infradead.org> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Chandan Rajendra <chandan@linux.ibm.com> Cc: Souptick Joarder <jrdr.linux@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | dax: make use of ->free_inode()Al Viro2019-05-021-5/+2
|/ | | | | | | | | | we might want to drop ->destroy_inode() there - it's used only for WARN_ON() now, and AFAICS that could be moved to ->evict_inode() if we had one... Reviewed-by: Jan Kara <jack@suse.cz> Acked-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Merge tag 'devdax-for-5.1' of ↵Linus Torvalds2019-03-1615-499/+1032
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm Pull device-dax updates from Dan Williams: "New device-dax infrastructure to allow persistent memory and other "reserved" / performance differentiated memories, to be assigned to the core-mm as "System RAM". Some users want to use persistent memory as additional volatile memory. They are willing to cope with potential performance differences, for example between DRAM and 3D Xpoint, and want to use typical Linux memory management apis rather than a userspace memory allocator layered over an mmap() of a dax file. The administration model is to decide how much Persistent Memory (pmem) to use as System RAM, create a device-dax-mode namespace of that size, and then assign it to the core-mm. The rationale for device-dax is that it is a generic memory-mapping driver that can be layered over any "special purpose" memory, not just pmem. On subsequent boots udev rules can be used to restore the memory assignment. One implication of using pmem as RAM is that mlock() no longer keeps data off persistent media. For this reason it is recommended to enable NVDIMM Security (previously merged for 5.0) to encrypt pmem contents at rest. We considered making this recommendation an actively enforced requirement, but in the end decided to leave it as a distribution / administrator policy to allow for emulation and test environments that lack security capable NVDIMMs. Summary: - Replace the /sys/class/dax device model with /sys/bus/dax, and include a compat driver so distributions can opt-in to the new ABI. - Allow for an alternative driver for the device-dax address-range - Introduce the 'kmem' driver to hotplug / assign a device-dax address-range to the core-mm. - Arrange for the device-dax target-node to be onlined so that the newly added memory range can be uniquely referenced by numa apis" NOTE! I'm not entirely happy with the whole "PMEM as RAM" model because we currently have special - and very annoying rules in the kernel about accessing PMEM only with the "MC safe" accessors, because machine checks inside the regular repeat string copy functions can be fatal in some (not described) circumstances. And apparently the PMEM modules can cause that a lot more than regular RAM. The argument is that this happens because PMEM doesn't necessarily get scrubbed at boot like RAM does, but that is planned to be added for the user space tooling. Quoting Dan from another email: "The exposure can be reduced in the volatile-RAM case by scanning for and clearing errors before it is onlined as RAM. The userspace tooling for that can be in place before v5.1-final. There's also runtime notifications of errors via acpi_nfit_uc_error_notify() from background scrubbers on the DIMM devices. With that mechanism the kernel could proactively clear newly discovered poison in the volatile case, but that would be additional development more suitable for v5.2. I understand the concern, and the need to highlight this issue by tapping the brakes on feature development, but I don't see PMEM as RAM making the situation worse when the exposure is also there via DAX in the PMEM case. Volatile-RAM is arguably a safer use case since it's possible to repair pages where the persistent case needs active application coordination" * tag 'devdax-for-5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: device-dax: "Hotplug" persistent memory for use like normal RAM mm/resource: Let walk_system_ram_range() search child resources mm/memory-hotplug: Allow memory resources to be children mm/resource: Move HMM pr_debug() deeper into resource code mm/resource: Return real error codes from walk failures device-dax: Add a 'modalias' attribute to DAX 'bus' devices device-dax: Add a 'target_node' attribute device-dax: Auto-bind device after successful new_id acpi/nfit, device-dax: Identify differentiated memory with a unique numa-node device-dax: Add /sys/class/dax backwards compatibility device-dax: Add support for a dax override driver device-dax: Move resource pinning+mapping into the common driver device-dax: Introduce bus + driver model device-dax: Start defining a dax bus model device-dax: Remove multi-resource infrastructure device-dax: Kill dax_region base device-dax: Kill dax_region ida
| * device-dax: "Hotplug" persistent memory for use like normal RAMDave Hansen2019-02-283-0/+125
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is intended for use with NVDIMMs that are physically persistent (physically like flash) so that they can be used as a cost-effective RAM replacement. Intel Optane DC persistent memory is one implementation of this kind of NVDIMM. Currently, a persistent memory region is "owned" by a device driver, either the "Direct DAX" or "Filesystem DAX" drivers. These drivers allow applications to explicitly use persistent memory, generally by being modified to use special, new libraries. (DIMM-based persistent memory hardware/software is described in great detail here: Documentation/nvdimm/nvdimm.txt). However, this limits persistent memory use to applications which *have* been modified. To make it more broadly usable, this driver "hotplugs" memory into the kernel, to be managed and used just like normal RAM would be. To make this work, management software must remove the device from being controlled by the "Device DAX" infrastructure: echo dax0.0 > /sys/bus/dax/drivers/device_dax/unbind and then tell the new driver that it can bind to the device: echo dax0.0 > /sys/bus/dax/drivers/kmem/new_id After this, there will be a number of new memory sections visible in sysfs that can be onlined, or that may get onlined by existing udev-initiated memory hotplug rules. This rebinding procedure is currently a one-way trip. Once memory is bound to "kmem", it's there permanently and can not be unbound and assigned back to device_dax. The kmem driver will never bind to a dax device unless the device is *explicitly* bound to the driver. There are two reasons for this: One, since it is a one-way trip, it can not be undone if bound incorrectly. Two, the kmem driver destroys data on the device. Think of if you had good data on a pmem device. It would be catastrophic if you compile-in "kmem", but leave out the "device_dax" driver. kmem would take over the device and write volatile data all over your good data. This inherits any existing NUMA information for the newly-added memory from the persistent memory device that came from the firmware. On Intel platforms, the firmware has guarantees that require each socket's persistent memory to be in a separate memory-only NUMA node. That means that this patch is not expected to create NUMA nodes, but will simply hotplug memory into existing nodes. Because NUMA nodes are created, the existing NUMA APIs and tools are sufficient to create policies for applications or memory areas to have affinity for or an aversion to using this memory. There is currently some metadata at the beginning of pmem regions. The section-size memory hotplug restrictions, plus this small reserved area can cause the "loss" of a section or two of capacity. This should be fixable in follow-on patches. But, as a first step, losing 256MB of memory (worst case) out of hundreds of gigabytes is a good tradeoff vs. the required code to fix this up precisely. This calculation is also the reason we export memory_block_size_bytes(). Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Keith Busch <keith.busch@intel.com> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Ross Zwisler <zwisler@kernel.org> Cc: Vishal Verma <vishal.l.verma@intel.com> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Michal Hocko <mhocko@suse.com> Cc: linux-nvdimm@lists.01.org Cc: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org Cc: Huang Ying <ying.huang@intel.com> Cc: Fengguang Wu <fengguang.wu@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Yaowei Bai <baiyaowei@cmss.chinamobile.com> Cc: Takashi Iwai <tiwai@suse.de> Cc: Jerome Glisse <jglisse@redhat.com> Reviewed-by: Vishal Verma <vishal.l.verma@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
| * device-dax: Add a 'modalias' attribute to DAX 'bus' devicesVishal Verma2019-02-281-0/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add a 'modalias' attribute to devices under the DAX bus so that userspace is able to dynamically load modules as needed. Normally, udev can get the modalias from 'uevent', and that is correctly set up by the DAX bus. However other tooling such as 'libndctl' for interacting with drivers/nvdimm/, and 'libdaxctl' for drivers/dax/ can also use the modalias to dynamically load modules via libkmod lookups. The 'nd' bus set up by the libnvdimm subsystem exports a modalias attribute. Imitate this to export the same for the 'dax' bus. Cc: Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by: Vishal Verma <vishal.l.verma@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
| * device-dax: Add a 'target_node' attributeDan Williams2019-02-201-0/+28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The target-node attribute is the Linux numa-node that a device-dax instance may create when it is online. Prior to being online the device's 'numa_node' property reflects the closest online cpu node which is the typical expectation of a device 'numa_node'. Once it is online it becomes its own distinct numa node, i.e. 'target_node'. Export the 'target_node' property to give userspace tooling the ability to predict the effective numa-node from a device-dax instance configured to provide 'System RAM' capacity. Cc: Vishal Verma <vishal.l.verma@intel.com> Reported-by: Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
| * device-dax: Auto-bind device after successful new_idDan Williams2019-01-241-6/+18
| | | | | | | | | | | | | | | | | | | | | | The typical 'new_id' attribute behavior is to immediately attach a device to its driver after a new device-id is added. Implement this behavior for the dax bus. Reported-by: Alexander Duyck <alexander.h.duyck@linux.intel.com> Reported-by: Brice Goglin <Brice.Goglin@inria.fr> Cc: Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
| * acpi/nfit, device-dax: Identify differentiated memory with a unique numa-nodeDan Williams2019-01-074-3/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Persistent memory, as described by the ACPI NFIT (NVDIMM Firmware Interface Table), is the first known instance of a memory range described by a unique "target" proximity domain. Where "initiator" and "target" proximity domains is an approach that the ACPI HMAT (Heterogeneous Memory Attributes Table) uses to described the unique performance properties of a memory range relative to a given initiator (e.g. CPU or DMA device). Currently the numa-node for a /dev/pmemX block-device or /dev/daxX.Y char-device follows the traditional notion of 'numa-node' where the attribute conveys the closest online numa-node. That numa-node attribute is useful for cpu-binding and memory-binding processes *near* the device. However, when the memory range backing a 'pmem', or 'dax' device is onlined (memory hot-add) the memory-only-numa-node representing that address needs to be differentiated from the set of online nodes. In other words, the numa-node association of the device depends on whether you can bind processes *near* the cpu-numa-node in the offline device-case, or bind process *on* the memory-range directly after the backing address range is onlined. Allow for the case that platform firmware describes persistent memory with a unique proximity domain, i.e. when it is distinct from the proximity of DRAM and CPUs that are on the same socket. Plumb the Linux numa-node translation of that proximity through the libnvdimm region device to namespaces that are in device-dax mode. With this in place the proposed kmem driver [1] can optionally discover a unique numa-node number for the address range as it transitions the memory from an offline state managed by a device-driver to an online memory range managed by the core-mm. [1]: https://lore.kernel.org/lkml/20181022201317.8558C1D8@viggo.jf.intel.com Reported-by: Fan Du <fan.du@intel.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: "Oliver O'Halloran" <oohall@gmail.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Jérôme Glisse <jglisse@redhat.com> Reviewed-by: Yang Shi <yang.shi@linux.alibaba.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
| * device-dax: Add /sys/class/dax backwards compatibilityDan Williams2019-01-079-49/+202
| | | | | | | | | | | | | | | | | | | | | | | | | | | | On the expectation that some environments may not upgrade libdaxctl (userspace component that depends on the /sys/class/dax hierarchy), provide a default / legacy dax_pmem_compat driver. The dax_pmem_compat driver implements the original /sys/class/dax sysfs layout rather than /sys/bus/dax. When userspace is upgraded it can blacklist this module and switch to the dax_pmem driver going forward. CONFIG_DEV_DAX_PMEM_COMPAT and supporting code will be deleted according to the dax_pmem entry in Documentation/ABI/obsolete/. Signed-off-by: Dan Williams <dan.j.williams@intel.com>
| * device-dax: Add support for a dax override driverDan Williams2019-01-073-10/+156
| | | | | | | | | | | | | | | | | | | | | | Introduce the 'new_id' concept for enabling a custom device-driver attach policy for dax-bus drivers. The intended use is to have a mechanism for hot-plugging device-dax ranges into the page allocator on-demand. With this in place the default policy of using device-dax for performance differentiated memory can be overridden by user-space policy that can arrange for the memory range to be managed as 'System RAM' with user-defined NUMA and other performance attributes. Signed-off-by: Dan Williams <dan.j.williams@intel.com>
| * device-dax: Move resource pinning+mapping into the common driverDan Williams2019-01-075-79/+90
| | | | | | | | | | | | | | | | Move the responsibility of calling devm_request_resource() and devm_memremap_pages() into the common device-dax driver. This is another preparatory step to allowing an alternate personality driver for a device-dax range. Signed-off-by: Dan Williams <dan.j.williams@intel.com>
| * device-dax: Introduce bus + driver modelDan Williams2019-01-075-87/+203
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In support of multiple device-dax instances per device-dax-region and allowing the 'kmem' driver to attach to dax-instances instead of the current device-node access, convert the dax sub-system from a class to a bus. Recall that the kmem driver takes reserved / special purpose memories and assigns them to be managed by the core-mm. Aside from the fact the device-dax instances are registered and probed on a bus, two other lifetime-management changes are made: 1/ Delay attaching a cdev until driver probe time 2/ A new run_dax() helper is introduced to allow restoring dax-operation after a kill_dax() event. So, at driver ->probe() time we run_dax() and at ->remove() time we kill_dax() and invalidate all mappings. Signed-off-by: Dan Williams <dan.j.williams@intel.com>
| * device-dax: Start defining a dax bus modelDan Williams2019-01-079-224/+209
| | | | | | | | | | | | | | | | | | | | | | | | | | Towards eliminating the dax_class, move the dax-device-attribute enabling to a new bus.c file in the core. The amount of code thrash of sub-sequent patches is reduced as no logic changes are made, just pure code movement. A temporary export of unregister_dex_dax() and dax_attribute_groups is needed to preserve compilation, but those symbols become static again in a follow-on patch. Signed-off-by: Dan Williams <dan.j.williams@intel.com>
| * device-dax: Remove multi-resource infrastructureDan Williams2019-01-074-49/+10
| | | | | | | | | | | | | | | | The multi-resource implementation anticipated discontiguous sub-division support. That has not yet materialized, delete the infrastructure and related code. Signed-off-by: Dan Williams <dan.j.williams@intel.com>
| * device-dax: Kill dax_region baseDan Williams2019-01-074-8/+4
| | | | | | | | | | | | | | Nothing consumes this attribute of a region and devres otherwise remembers the value for de-allocation purposes. Signed-off-by: Dan Williams <dan.j.williams@intel.com>
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-14 11:46:46 +0100