Re: [patch 05/10] mm: filemap: move radix tree hole searching here
On Mon, Feb 03, 2014 at 07:53:37PM -0500, Johannes Weiner wrote: > The radix tree hole searching code is only used for page cache, for > example the readahead code trying to get a a picture of the area > surrounding a fault. > > It sufficed to rely on the radix tree definition of holes, which is > "empty tree slot". But this is about to change, though, as shadow > page descriptors will be stored in the page cache after the actual > pages get evicted from memory. > > Move the functions over to mm/filemap.c and make them native page > cache operations, where they can later be adapted to handle the new > definition of "page cache hole". > > Signed-off-by: Johannes Weiner > Reviewed-by: Rik van Riel > Reviewed-by: Minchan Kim Acked-by: Mel Gorman -- Mel Gorman SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [patch 05/10] mm: filemap: move radix tree hole searching here
On Mon, Feb 03, 2014 at 07:53:37PM -0500, Johannes Weiner wrote: The radix tree hole searching code is only used for page cache, for example the readahead code trying to get a a picture of the area surrounding a fault. It sufficed to rely on the radix tree definition of holes, which is empty tree slot. But this is about to change, though, as shadow page descriptors will be stored in the page cache after the actual pages get evicted from memory. Move the functions over to mm/filemap.c and make them native page cache operations, where they can later be adapted to handle the new definition of page cache hole. Signed-off-by: Johannes Weiner han...@cmpxchg.org Reviewed-by: Rik van Riel r...@redhat.com Reviewed-by: Minchan Kim minc...@kernel.org Acked-by: Mel Gorman mgor...@suse.de -- Mel Gorman SUSE Labs -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[patch 05/10] mm: filemap: move radix tree hole searching here
The radix tree hole searching code is only used for page cache, for
example the readahead code trying to get a a picture of the area
surrounding a fault.
It sufficed to rely on the radix tree definition of holes, which is
"empty tree slot". But this is about to change, though, as shadow
page descriptors will be stored in the page cache after the actual
pages get evicted from memory.
Move the functions over to mm/filemap.c and make them native page
cache operations, where they can later be adapted to handle the new
definition of "page cache hole".
Signed-off-by: Johannes Weiner
Reviewed-by: Rik van Riel
Reviewed-by: Minchan Kim
---
fs/nfs/blocklayout/blocklayout.c | 2 +-
include/linux/pagemap.h | 5 +++
include/linux/radix-tree.h | 4 ---
lib/radix-tree.c | 75 ---
mm/filemap.c | 76
mm/readahead.c | 4 +--
6 files changed, 84 insertions(+), 82 deletions(-)
diff --git a/fs/nfs/blocklayout/blocklayout.c b/fs/nfs/blocklayout/blocklayout.c
index 56ff823ca82e..65d849bdf77a 100644
--- a/fs/nfs/blocklayout/blocklayout.c
+++ b/fs/nfs/blocklayout/blocklayout.c
@@ -1213,7 +1213,7 @@ static u64 pnfs_num_cont_bytes(struct inode *inode,
pgoff_t idx)
end = DIV_ROUND_UP(i_size_read(inode), PAGE_CACHE_SIZE);
if (end != NFS_I(inode)->npages) {
rcu_read_lock();
- end = radix_tree_next_hole(>page_tree, idx + 1,
ULONG_MAX);
+ end = page_cache_next_hole(mapping, idx + 1, ULONG_MAX);
rcu_read_unlock();
}
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 1710d1b060ba..52d56872fe26 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -243,6 +243,11 @@ static inline struct page
*page_cache_alloc_readahead(struct address_space *x)
typedef int filler_t(void *, struct page *);
+pgoff_t page_cache_next_hole(struct address_space *mapping,
+pgoff_t index, unsigned long max_scan);
+pgoff_t page_cache_prev_hole(struct address_space *mapping,
+pgoff_t index, unsigned long max_scan);
+
extern struct page * find_get_page(struct address_space *mapping,
pgoff_t index);
extern struct page * find_lock_page(struct address_space *mapping,
diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h
index 1bf0a9c388d9..e8be53ecfc45 100644
--- a/include/linux/radix-tree.h
+++ b/include/linux/radix-tree.h
@@ -227,10 +227,6 @@ radix_tree_gang_lookup(struct radix_tree_root *root, void
**results,
unsigned int radix_tree_gang_lookup_slot(struct radix_tree_root *root,
void ***results, unsigned long *indices,
unsigned long first_index, unsigned int max_items);
-unsigned long radix_tree_next_hole(struct radix_tree_root *root,
- unsigned long index, unsigned long max_scan);
-unsigned long radix_tree_prev_hole(struct radix_tree_root *root,
- unsigned long index, unsigned long max_scan);
int radix_tree_preload(gfp_t gfp_mask);
int radix_tree_maybe_preload(gfp_t gfp_mask);
void radix_tree_init(void);
diff --git a/lib/radix-tree.c b/lib/radix-tree.c
index f442e3243607..e8adb5d8a184 100644
--- a/lib/radix-tree.c
+++ b/lib/radix-tree.c
@@ -946,81 +946,6 @@ next:
}
EXPORT_SYMBOL(radix_tree_range_tag_if_tagged);
-
-/**
- * radix_tree_next_hole-find the next hole (not-present entry)
- * @root: tree root
- * @index: index key
- * @max_scan: maximum range to search
- *
- * Search the set [index, min(index+max_scan-1, MAX_INDEX)] for the lowest
- * indexed hole.
- *
- * Returns: the index of the hole if found, otherwise returns an index
- * outside of the set specified (in which case 'return - index >= max_scan'
- * will be true). In rare cases of index wrap-around, 0 will be returned.
- *
- * radix_tree_next_hole may be called under rcu_read_lock. However, like
- * radix_tree_gang_lookup, this will not atomically search a snapshot of
- * the tree at a single point in time. For example, if a hole is created
- * at index 5, then subsequently a hole is created at index 10,
- * radix_tree_next_hole covering both indexes may return 10 if called
- * under rcu_read_lock.
- */
-unsigned long radix_tree_next_hole(struct radix_tree_root *root,
- unsigned long index, unsigned long max_scan)
-{
- unsigned long i;
-
- for (i = 0; i < max_scan; i++) {
- if (!radix_tree_lookup(root, index))
- break;
- index++;
- if (index == 0)
- break;
- }
-
- return index;
-}
-EXPORT_SYMBOL(radix_tree_next_hole);
-
-/**
- * radix_tree_prev_hole-find the prev hole
[patch 05/10] mm: filemap: move radix tree hole searching here
The radix tree hole searching code is only used for page cache, for
example the readahead code trying to get a a picture of the area
surrounding a fault.
It sufficed to rely on the radix tree definition of holes, which is
empty tree slot. But this is about to change, though, as shadow
page descriptors will be stored in the page cache after the actual
pages get evicted from memory.
Move the functions over to mm/filemap.c and make them native page
cache operations, where they can later be adapted to handle the new
definition of page cache hole.
Signed-off-by: Johannes Weiner han...@cmpxchg.org
Reviewed-by: Rik van Riel r...@redhat.com
Reviewed-by: Minchan Kim minc...@kernel.org
---
fs/nfs/blocklayout/blocklayout.c | 2 +-
include/linux/pagemap.h | 5 +++
include/linux/radix-tree.h | 4 ---
lib/radix-tree.c | 75 ---
mm/filemap.c | 76
mm/readahead.c | 4 +--
6 files changed, 84 insertions(+), 82 deletions(-)
diff --git a/fs/nfs/blocklayout/blocklayout.c b/fs/nfs/blocklayout/blocklayout.c
index 56ff823ca82e..65d849bdf77a 100644
--- a/fs/nfs/blocklayout/blocklayout.c
+++ b/fs/nfs/blocklayout/blocklayout.c
@@ -1213,7 +1213,7 @@ static u64 pnfs_num_cont_bytes(struct inode *inode,
pgoff_t idx)
end = DIV_ROUND_UP(i_size_read(inode), PAGE_CACHE_SIZE);
if (end != NFS_I(inode)-npages) {
rcu_read_lock();
- end = radix_tree_next_hole(mapping-page_tree, idx + 1,
ULONG_MAX);
+ end = page_cache_next_hole(mapping, idx + 1, ULONG_MAX);
rcu_read_unlock();
}
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 1710d1b060ba..52d56872fe26 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -243,6 +243,11 @@ static inline struct page
*page_cache_alloc_readahead(struct address_space *x)
typedef int filler_t(void *, struct page *);
+pgoff_t page_cache_next_hole(struct address_space *mapping,
+pgoff_t index, unsigned long max_scan);
+pgoff_t page_cache_prev_hole(struct address_space *mapping,
+pgoff_t index, unsigned long max_scan);
+
extern struct page * find_get_page(struct address_space *mapping,
pgoff_t index);
extern struct page * find_lock_page(struct address_space *mapping,
diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h
index 1bf0a9c388d9..e8be53ecfc45 100644
--- a/include/linux/radix-tree.h
+++ b/include/linux/radix-tree.h
@@ -227,10 +227,6 @@ radix_tree_gang_lookup(struct radix_tree_root *root, void
**results,
unsigned int radix_tree_gang_lookup_slot(struct radix_tree_root *root,
void ***results, unsigned long *indices,
unsigned long first_index, unsigned int max_items);
-unsigned long radix_tree_next_hole(struct radix_tree_root *root,
- unsigned long index, unsigned long max_scan);
-unsigned long radix_tree_prev_hole(struct radix_tree_root *root,
- unsigned long index, unsigned long max_scan);
int radix_tree_preload(gfp_t gfp_mask);
int radix_tree_maybe_preload(gfp_t gfp_mask);
void radix_tree_init(void);
diff --git a/lib/radix-tree.c b/lib/radix-tree.c
index f442e3243607..e8adb5d8a184 100644
--- a/lib/radix-tree.c
+++ b/lib/radix-tree.c
@@ -946,81 +946,6 @@ next:
}
EXPORT_SYMBOL(radix_tree_range_tag_if_tagged);
-
-/**
- * radix_tree_next_hole-find the next hole (not-present entry)
- * @root: tree root
- * @index: index key
- * @max_scan: maximum range to search
- *
- * Search the set [index, min(index+max_scan-1, MAX_INDEX)] for the lowest
- * indexed hole.
- *
- * Returns: the index of the hole if found, otherwise returns an index
- * outside of the set specified (in which case 'return - index = max_scan'
- * will be true). In rare cases of index wrap-around, 0 will be returned.
- *
- * radix_tree_next_hole may be called under rcu_read_lock. However, like
- * radix_tree_gang_lookup, this will not atomically search a snapshot of
- * the tree at a single point in time. For example, if a hole is created
- * at index 5, then subsequently a hole is created at index 10,
- * radix_tree_next_hole covering both indexes may return 10 if called
- * under rcu_read_lock.
- */
-unsigned long radix_tree_next_hole(struct radix_tree_root *root,
- unsigned long index, unsigned long max_scan)
-{
- unsigned long i;
-
- for (i = 0; i max_scan; i++) {
- if (!radix_tree_lookup(root, index))
- break;
- index++;
- if (index == 0)
- break;
- }
-
- return index;
-}
-EXPORT_SYMBOL(radix_tree_next_hole);
-
-/**
- *
