Commit 70dec807 authored by Chris Mason's avatar Chris Mason
Browse files

Btrfs: extent_io and extent_state optimizations 



The end_bio routines are changed to take a pointer to the extent state
struct, and the state tree is walked in order to set/clear appropriate
bits as IO completes.  This greatly reduces the number of rbtree searches
done by the end_bio handlers, and reduces lock contention.

The extent_io releasepage function is changed to avoid expensive searches
for locked state.

Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent aadfeb6e

fs/btrfs/disk-io.c

+2 −2
Original line number Diff line number Diff line
@@ -274,7 +274,7 @@ int btree_readpage(struct file *file, struct page *page) 
	return extent_read_full_page(tree, page, btree_get_extent);

}



static int btree_releasepage(struct page *page, gfp_t unused_gfp_flags)

static int btree_releasepage(struct page *page, gfp_t gfp_flags)

{

	struct extent_io_tree *tree;

	struct extent_map_tree *map;
@@ -282,7 +282,7 @@ static int btree_releasepage(struct page *page, gfp_t unused_gfp_flags) 


	tree = &BTRFS_I(page->mapping->host)->io_tree;

	map = &BTRFS_I(page->mapping->host)->extent_tree;

	ret = try_release_extent_mapping(map, tree, page);

	ret = try_release_extent_mapping(map, tree, page, gfp_flags);

	if (ret == 1) {

		ClearPagePrivate(page);

		set_page_private(page, 0);

fs/btrfs/extent_io.c

+263 −95

File changed.

Preview size limit exceeded, changes collapsed.

fs/btrfs/extent_io.h

+10 −5
Original line number Diff line number Diff line
@@ -23,19 +23,23 @@ 
#define EXTENT_PAGE_PRIVATE 1

#define EXTENT_PAGE_PRIVATE_FIRST_PAGE 3



struct extent_state;



struct extent_io_ops {

	int (*fill_delalloc)(struct inode *inode, u64 start, u64 end);

	int (*writepage_io_hook)(struct page *page, u64 start, u64 end);

	int (*readpage_io_hook)(struct page *page, u64 start, u64 end);

	int (*readpage_end_io_hook)(struct page *page, u64 start, u64 end);

	void (*writepage_end_io_hook)(struct page *page, u64 start, u64 end);

	int (*readpage_end_io_hook)(struct page *page, u64 start, u64 end,

				    struct extent_state *state);

	void (*writepage_end_io_hook)(struct page *page, u64 start, u64 end,

				      struct extent_state *state);

};



struct extent_io_tree {

	struct rb_root state;

	struct address_space *mapping;

	u64 dirty_bytes;

	rwlock_t lock;

	spinlock_t lock;

	struct extent_io_ops *ops;

	spinlock_t lru_lock;

	struct list_head buffer_lru;
@@ -45,8 +49,8 @@ struct extent_io_tree { 
struct extent_state {

	u64 start;

	u64 end; /* inclusive */

	int in_tree;

	struct rb_node rb_node;

	struct extent_io_tree *tree;

	wait_queue_head_t wq;

	atomic_t refs;

	unsigned long state;
@@ -82,7 +86,8 @@ void extent_io_tree_init(struct extent_io_tree *tree, 
			  struct address_space *mapping, gfp_t mask);

void extent_io_tree_empty_lru(struct extent_io_tree *tree);

int try_release_extent_mapping(struct extent_map_tree *map,

			       struct extent_io_tree *tree, struct page *page);

			       struct extent_io_tree *tree, struct page *page,

			       gfp_t mask);

int lock_extent(struct extent_io_tree *tree, u64 start, u64 end, gfp_t mask);

int unlock_extent(struct extent_io_tree *tree, u64 start, u64 end, gfp_t mask);

int extent_read_full_page(struct extent_io_tree *tree, struct page *page,

fs/btrfs/inode.c

+23 −12
Original line number Diff line number Diff line
@@ -331,7 +331,8 @@ out: 
	return ret;

}



int btrfs_readpage_end_io_hook(struct page *page, u64 start, u64 end)

int btrfs_readpage_end_io_hook(struct page *page, u64 start, u64 end,

			       struct extent_state *state)

{

	size_t offset = start - ((u64)page->index << PAGE_CACHE_SHIFT);

	struct inode *inode = page->mapping->host;
@@ -347,7 +348,12 @@ int btrfs_readpage_end_io_hook(struct page *page, u64 start, u64 end) 
	    btrfs_test_flag(inode, NODATASUM))

		return 0;



	if (state->start == start) {

		private = state->private;

		ret = 0;

	} else {

		ret = get_state_private(io_tree, start, &private);

	}

	local_irq_save(flags);

	kaddr = kmap_atomic(page, KM_IRQ0);

	if (ret) {
@@ -1830,7 +1836,7 @@ out_unlock: 
}



struct extent_map *btrfs_get_extent(struct inode *inode, struct page *page,

				    size_t page_offset, u64 start, u64 len,

				    size_t pg_offset, u64 start, u64 len,

				    int create)

{

	int ret;
@@ -1865,6 +1871,9 @@ again: 
			       start, len, em->start, em->len);

			WARN_ON(1);

		}

		if (em->block_start == EXTENT_MAP_INLINE && page)

			free_extent_map(em);

		else

			goto out;

	}

	em = alloc_extent_map(GFP_NOFS);
@@ -1930,6 +1939,7 @@ again: 
		em->len = extent_end - extent_start;

		goto insert;

	} else if (found_type == BTRFS_FILE_EXTENT_INLINE) {

		u64 page_start;

		unsigned long ptr;

		char *map;

		size_t size;
@@ -1959,16 +1969,17 @@ again: 
			goto out;

		}



		extent_offset = ((u64)page->index << PAGE_CACHE_SHIFT) -

			extent_start + page_offset;

		copy_size = min_t(u64, PAGE_CACHE_SIZE - page_offset,

		page_start = page_offset(page) + pg_offset;

		extent_offset = page_start - extent_start;

		copy_size = min_t(u64, PAGE_CACHE_SIZE - pg_offset,

				size - extent_offset);

		em->start = extent_start + extent_offset;

		em->len = copy_size;

		em->len = (copy_size + root->sectorsize - 1) &

			~((u64)root->sectorsize - 1);

		map = kmap(page);

		ptr = btrfs_file_extent_inline_start(item) + extent_offset;

		if (create == 0 && !PageUptodate(page)) {

			read_extent_buffer(leaf, map + page_offset, ptr,

			read_extent_buffer(leaf, map + pg_offset, ptr,

					   copy_size);

			flush_dcache_page(page);

		} else if (create && PageUptodate(page)) {
@@ -1980,7 +1991,7 @@ again: 
				trans = btrfs_start_transaction(root, 1);

				goto again;

			}

			write_extent_buffer(leaf, map + page_offset, ptr,

			write_extent_buffer(leaf, map + pg_offset, ptr,

					    copy_size);

			btrfs_mark_buffer_dirty(leaf);

		}
@@ -2077,7 +2088,7 @@ btrfs_readpages(struct file *file, struct address_space *mapping, 
				btrfs_get_extent);

}



static int btrfs_releasepage(struct page *page, gfp_t unused_gfp_flags)

static int btrfs_releasepage(struct page *page, gfp_t gfp_flags)

{

	struct extent_io_tree *tree;

	struct extent_map_tree *map;
@@ -2085,7 +2096,7 @@ static int btrfs_releasepage(struct page *page, gfp_t unused_gfp_flags) 


	tree = &BTRFS_I(page->mapping->host)->io_tree;

	map = &BTRFS_I(page->mapping->host)->extent_tree;

	ret = try_release_extent_mapping(map, tree, page);

	ret = try_release_extent_mapping(map, tree, page, gfp_flags);

	if (ret == 1) {

		ClearPagePrivate(page);

		set_page_private(page, 0);

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