diff options
| author | Ross Zwisler <ross.zwisler@linux.intel.com> | 2016-01-23 02:10:40 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-01-23 04:02:18 +0300 |
| commit | f9fe48bece3af2d60e1bad65db4825f5a025dd36 (patch) | |
| tree | 78f56ae2a1636fa9f8ec26466d4a94a16eadd5dc /include/linux/fs.h | |
| parent | 3f4a2670deea53e3765e24a7f46aafe6f077cb68 (diff) | |
| download | linux-f9fe48bece3af2d60e1bad65db4825f5a025dd36.tar.xz | |
dax: support dirty DAX entries in radix tree
Add support for tracking dirty DAX entries in the struct address_space
radix tree. This tree is already used for dirty page writeback, and it
already supports the use of exceptional (non struct page*) entries.
In order to properly track dirty DAX pages we will insert new
exceptional entries into the radix tree that represent dirty DAX PTE or
PMD pages. These exceptional entries will also contain the writeback
addresses for the PTE or PMD faults that we can use at fsync/msync time.
There are currently two types of exceptional entries (shmem and shadow)
that can be placed into the radix tree, and this adds a third. We rely
on the fact that only one type of exceptional entry can be found in a
given radix tree based on its usage. This happens for free with DAX vs
shmem but we explicitly prevent shadow entries from being added to radix
trees for DAX mappings.
The only shadow entries that would be generated for DAX radix trees
would be to track zero page mappings that were created for holes. These
pages would receive minimal benefit from having shadow entries, and the
choice to have only one type of exceptional entry in a given radix tree
makes the logic simpler both in clear_exceptional_entry() and in the
rest of DAX.
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jan Kara <jack@suse.com>
Cc: Jeff Layton <jlayton@poochiereds.net>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/fs.h')
| -rw-r--r-- | include/linux/fs.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/include/linux/fs.h b/include/linux/fs.h index eb73d74ed992..0d7570320d63 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -433,7 +433,8 @@ struct address_space { struct rw_semaphore i_mmap_rwsem; /* protect tree, count, list */ /* Protected by tree_lock together with the radix tree */ unsigned long nrpages; /* number of total pages */ - unsigned long nrshadows; /* number of shadow entries */ + /* number of shadow or DAX exceptional entries */ + unsigned long nrexceptional; pgoff_t writeback_index;/* writeback starts here */ const struct address_space_operations *a_ops; /* methods */ unsigned long flags; /* error bits/gfp mask */ |