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authorRoss Zwisler <ross.zwisler@linux.intel.com>2016-01-23 02:10:40 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2016-01-23 04:02:18 +0300
commitf9fe48bece3af2d60e1bad65db4825f5a025dd36 (patch)
tree78f56ae2a1636fa9f8ec26466d4a94a16eadd5dc /include/linux/radix-tree.h
parent3f4a2670deea53e3765e24a7f46aafe6f077cb68 (diff)
downloadlinux-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/radix-tree.h')
-rw-r--r--include/linux/radix-tree.h9
1 files changed, 9 insertions, 0 deletions
diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h
index 57e7d87d2d4c..7c88ad156a29 100644
--- a/include/linux/radix-tree.h
+++ b/include/linux/radix-tree.h
@@ -51,6 +51,15 @@
#define RADIX_TREE_EXCEPTIONAL_ENTRY 2
#define RADIX_TREE_EXCEPTIONAL_SHIFT 2
+#define RADIX_DAX_MASK 0xf
+#define RADIX_DAX_SHIFT 4
+#define RADIX_DAX_PTE (0x4 | RADIX_TREE_EXCEPTIONAL_ENTRY)
+#define RADIX_DAX_PMD (0x8 | RADIX_TREE_EXCEPTIONAL_ENTRY)
+#define RADIX_DAX_TYPE(entry) ((unsigned long)entry & RADIX_DAX_MASK)
+#define RADIX_DAX_SECTOR(entry) (((unsigned long)entry >> RADIX_DAX_SHIFT))
+#define RADIX_DAX_ENTRY(sector, pmd) ((void *)((unsigned long)sector << \
+ RADIX_DAX_SHIFT | (pmd ? RADIX_DAX_PMD : RADIX_DAX_PTE)))
+
static inline int radix_tree_is_indirect_ptr(void *ptr)
{
return (int)((unsigned long)ptr & RADIX_TREE_INDIRECT_PTR);