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| author |   Dan Williams <dan.j.williams@intel.com> | 2016-05-18 09:15:08 -0700 |
|---|---|---|
| committer | Dan Williams <dan.j.williams@intel.com> | 2016-05-20 22:02:53 -0700 |
| commit | ab68f26221366f92611650e8470e6a926801c7d4 (patch) | |
| tree | a43178bfd901b84c6b65a6b293f03bc4c9d04076 /drivers/dax/dax.h | |
| parent | libnvdimm: stop requiring a driver ->remove() method (diff) | |
| download | linux-dev-ab68f26221366f92611650e8470e6a926801c7d4.tar.xz linux-dev-ab68f26221366f92611650e8470e6a926801c7d4.zip | |
/dev/dax, pmem: direct access to persistent memory
Device DAX is the device-centric analogue of Filesystem DAX
(CONFIG_FS_DAX). It allows memory ranges to be allocated and mapped
without need of an intervening file system. Device DAX is strict,
precise and predictable. Specifically this interface:
1/ Guarantees fault granularity with respect to a given page size (pte,
pmd, or pud) set at configuration time.
2/ Enforces deterministic behavior by being strict about what fault
scenarios are supported.
For example, by forcing MADV_DONTFORK semantics and omitting MAP_PRIVATE
support device-dax guarantees that a mapping always behaves/performs the
same once established. It is the "what you see is what you get" access
mechanism to differentiated memory vs filesystem DAX which has
filesystem specific implementation semantics.
Persistent memory is the first target, but the mechanism is also
targeted for exclusive allocations of performance differentiated memory
ranges.
This commit is limited to the base device driver infrastructure to
associate a dax device with pmem range.
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'drivers/dax/dax.h')
| -rw-r--r-- | drivers/dax/dax.h | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/drivers/dax/dax.h b/drivers/dax/dax.h new file mode 100644 index 000000000000..d8b8f1f25054 --- /dev/null +++ b/drivers/dax/dax.h @@ -0,0 +1,24 @@ +/* + * Copyright(c) 2016 Intel Corporation. All rights reserved. + * + * 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. + */ +#ifndef __DAX_H__ +#define __DAX_H__ +struct device; +struct resource; +struct dax_region; +void dax_region_put(struct dax_region *dax_region); +struct dax_region *alloc_dax_region(struct device *parent, + int region_id, struct resource *res, unsigned int align, + void *addr, unsigned long flags); +int devm_create_dax_dev(struct dax_region *dax_region, struct resource *res, + int count); +#endif /* __DAX_H__ */ |