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Btrfs: use a cached state for extent state operations during delalloc
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This changes the btrfs code to find delalloc ranges in the extent state
tree to use the new state caching code from set/test bit.  It reduces
one of the biggest causes of rbtree searches in the writeback path.

test_range_bit is also modified to take the cached state as a starting
point while searching.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
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Chris Mason committed Sep 11, 2009
1 parent d5550c6 commit 9655d29
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Showing 5 changed files with 40 additions and 24 deletions.
46 changes: 31 additions & 15 deletions fs/btrfs/extent_io.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -720,6 +720,13 @@ static int set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
}

spin_lock(&tree->lock);
if (cached_state && *cached_state) {
state = *cached_state;
if (state->start == start && state->tree) {
node = &state->rb_node;
goto hit_next;
}
}
/*
* this search will find all the extents that end after
* our range starts.
Expand Down Expand Up @@ -1286,6 +1293,7 @@ static noinline u64 find_lock_delalloc_range(struct inode *inode,
u64 delalloc_start;
u64 delalloc_end;
u64 found;
struct extent_state *cached_state = NULL;
int ret;
int loops = 0;

Expand Down Expand Up @@ -1323,6 +1331,7 @@ static noinline u64 find_lock_delalloc_range(struct inode *inode,
/* some of the pages are gone, lets avoid looping by
* shortening the size of the delalloc range we're searching
*/
free_extent_state(cached_state);
if (!loops) {
unsigned long offset = (*start) & (PAGE_CACHE_SIZE - 1);
max_bytes = PAGE_CACHE_SIZE - offset;
Expand All @@ -1336,18 +1345,21 @@ static noinline u64 find_lock_delalloc_range(struct inode *inode,
BUG_ON(ret);

/* step three, lock the state bits for the whole range */
lock_extent(tree, delalloc_start, delalloc_end, GFP_NOFS);
lock_extent_bits(tree, delalloc_start, delalloc_end,
0, &cached_state, GFP_NOFS);

/* then test to make sure it is all still delalloc */
ret = test_range_bit(tree, delalloc_start, delalloc_end,
EXTENT_DELALLOC, 1);
EXTENT_DELALLOC, 1, cached_state);
if (!ret) {
unlock_extent(tree, delalloc_start, delalloc_end, GFP_NOFS);
unlock_extent_cached(tree, delalloc_start, delalloc_end,
&cached_state, GFP_NOFS);
__unlock_for_delalloc(inode, locked_page,
delalloc_start, delalloc_end);
cond_resched();
goto again;
}
free_extent_state(cached_state);
*start = delalloc_start;
*end = delalloc_end;
out_failed:
Expand Down Expand Up @@ -1530,14 +1542,17 @@ int get_state_private(struct extent_io_tree *tree, u64 start, u64 *private)
* range is found set.
*/
int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
int bits, int filled)
int bits, int filled, struct extent_state *cached)
{
struct extent_state *state = NULL;
struct rb_node *node;
int bitset = 0;

spin_lock(&tree->lock);
node = tree_search(tree, start);
if (cached && cached->tree && cached->start == start)
node = &cached->rb_node;
else
node = tree_search(tree, start);
while (node && start <= end) {
state = rb_entry(node, struct extent_state, rb_node);

Expand Down Expand Up @@ -1580,7 +1595,7 @@ static int check_page_uptodate(struct extent_io_tree *tree,
{
u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
u64 end = start + PAGE_CACHE_SIZE - 1;
if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1))
if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1, NULL))
SetPageUptodate(page);
return 0;
}
Expand All @@ -1594,7 +1609,7 @@ static int check_page_locked(struct extent_io_tree *tree,
{
u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
u64 end = start + PAGE_CACHE_SIZE - 1;
if (!test_range_bit(tree, start, end, EXTENT_LOCKED, 0))
if (!test_range_bit(tree, start, end, EXTENT_LOCKED, 0, NULL))
unlock_page(page);
return 0;
}
Expand Down Expand Up @@ -2032,7 +2047,8 @@ static int __extent_read_full_page(struct extent_io_tree *tree,
continue;
}
/* the get_extent function already copied into the page */
if (test_range_bit(tree, cur, cur_end, EXTENT_UPTODATE, 1)) {
if (test_range_bit(tree, cur, cur_end,
EXTENT_UPTODATE, 1, NULL)) {
check_page_uptodate(tree, page);
unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
cur = cur + iosize;
Expand Down Expand Up @@ -2305,7 +2321,7 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
}
/* leave this out until we have a page_mkwrite call */
if (0 && !test_range_bit(tree, cur, cur + iosize - 1,
EXTENT_DIRTY, 0)) {
EXTENT_DIRTY, 0, NULL)) {
cur = cur + iosize;
pg_offset += iosize;
continue;
Expand Down Expand Up @@ -2721,7 +2737,7 @@ int extent_prepare_write(struct extent_io_tree *tree,
!isnew && !PageUptodate(page) &&
(block_off_end > to || block_off_start < from) &&
!test_range_bit(tree, block_start, cur_end,
EXTENT_UPTODATE, 1)) {
EXTENT_UPTODATE, 1, NULL)) {
u64 sector;
u64 extent_offset = block_start - em->start;
size_t iosize;
Expand Down Expand Up @@ -2776,7 +2792,7 @@ int try_release_extent_state(struct extent_map_tree *map,
int ret = 1;

if (test_range_bit(tree, start, end,
EXTENT_IOBITS | EXTENT_ORDERED, 0))
EXTENT_IOBITS | EXTENT_ORDERED, 0, NULL))
ret = 0;
else {
if ((mask & GFP_NOFS) == GFP_NOFS)
Expand Down Expand Up @@ -2821,7 +2837,7 @@ int try_release_extent_mapping(struct extent_map_tree *map,
extent_map_end(em) - 1,
EXTENT_LOCKED | EXTENT_WRITEBACK |
EXTENT_ORDERED,
0)) {
0, NULL)) {
remove_extent_mapping(map, em);
/* once for the rb tree */
free_extent_map(em);
Expand Down Expand Up @@ -3237,7 +3253,7 @@ int extent_range_uptodate(struct extent_io_tree *tree,
int uptodate;
unsigned long index;

ret = test_range_bit(tree, start, end, EXTENT_UPTODATE, 1);
ret = test_range_bit(tree, start, end, EXTENT_UPTODATE, 1, NULL);
if (ret)
return 1;
while (start <= end) {
Expand Down Expand Up @@ -3267,7 +3283,7 @@ int extent_buffer_uptodate(struct extent_io_tree *tree,
return 1;

ret = test_range_bit(tree, eb->start, eb->start + eb->len - 1,
EXTENT_UPTODATE, 1);
EXTENT_UPTODATE, 1, NULL);
if (ret)
return ret;

Expand Down Expand Up @@ -3303,7 +3319,7 @@ int read_extent_buffer_pages(struct extent_io_tree *tree,
return 0;

if (test_range_bit(tree, eb->start, eb->start + eb->len - 1,
EXTENT_UPTODATE, 1)) {
EXTENT_UPTODATE, 1, NULL)) {
return 0;
}

Expand Down
2 changes: 1 addition & 1 deletion fs/btrfs/extent_io.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -157,7 +157,7 @@ u64 count_range_bits(struct extent_io_tree *tree,
u64 max_bytes, unsigned long bits);

int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
int bits, int filled);
int bits, int filled, struct extent_state *cached_state);
int clear_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
int bits, gfp_t mask);
int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
Expand Down
6 changes: 3 additions & 3 deletions fs/btrfs/inode.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1376,7 +1376,7 @@ static void btrfs_writepage_fixup_worker(struct btrfs_work *work)

/* already ordered? We're done */
if (test_range_bit(&BTRFS_I(inode)->io_tree, page_start, page_end,
EXTENT_ORDERED, 0)) {
EXTENT_ORDERED, 0, NULL)) {
goto out;
}

Expand Down Expand Up @@ -1417,7 +1417,7 @@ static int btrfs_writepage_start_hook(struct page *page, u64 start, u64 end)
int ret;

ret = test_range_bit(&BTRFS_I(inode)->io_tree, start, end,
EXTENT_ORDERED, 0);
EXTENT_ORDERED, 0, NULL);
if (ret)
return 0;

Expand Down Expand Up @@ -1795,7 +1795,7 @@ static int btrfs_readpage_end_io_hook(struct page *page, u64 start, u64 end,
return 0;

if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID &&
test_range_bit(io_tree, start, end, EXTENT_NODATASUM, 1)) {
test_range_bit(io_tree, start, end, EXTENT_NODATASUM, 1, NULL)) {
clear_extent_bits(io_tree, start, end, EXTENT_NODATASUM,
GFP_NOFS);
return 0;
Expand Down
8 changes: 4 additions & 4 deletions fs/btrfs/ordered-data.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -262,7 +262,7 @@ int btrfs_dec_test_ordered_pending(struct inode *inode,

ret = test_range_bit(io_tree, entry->file_offset,
entry->file_offset + entry->len - 1,
EXTENT_ORDERED, 0);
EXTENT_ORDERED, 0, NULL);
if (ret == 0)
ret = test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
out:
Expand Down Expand Up @@ -522,7 +522,7 @@ int btrfs_wait_ordered_range(struct inode *inode, u64 start, u64 len)
end--;
}
if (test_range_bit(&BTRFS_I(inode)->io_tree, start, orig_end,
EXTENT_ORDERED | EXTENT_DELALLOC, 0)) {
EXTENT_ORDERED | EXTENT_DELALLOC, 0, NULL)) {
schedule_timeout(1);
goto again;
}
Expand Down Expand Up @@ -613,7 +613,7 @@ int btrfs_ordered_update_i_size(struct inode *inode,
*/
if (test_range_bit(io_tree, disk_i_size,
ordered->file_offset + ordered->len - 1,
EXTENT_DELALLOC, 0)) {
EXTENT_DELALLOC, 0, NULL)) {
goto out;
}
/*
Expand Down Expand Up @@ -664,7 +664,7 @@ int btrfs_ordered_update_i_size(struct inode *inode,
*/
if (i_size_test > entry_end(ordered) &&
!test_range_bit(io_tree, entry_end(ordered), i_size_test - 1,
EXTENT_DELALLOC, 0)) {
EXTENT_DELALLOC, 0, NULL)) {
new_i_size = min_t(u64, i_size_test, i_size_read(inode));
}
BTRFS_I(inode)->disk_i_size = new_i_size;
Expand Down
2 changes: 1 addition & 1 deletion fs/btrfs/relocation.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2180,7 +2180,7 @@ static int tree_block_processed(u64 bytenr, u32 blocksize,
struct reloc_control *rc)
{
if (test_range_bit(&rc->processed_blocks, bytenr,
bytenr + blocksize - 1, EXTENT_DIRTY, 1))
bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
return 1;
return 0;
}
Expand Down

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