Commit 929f4baf authored by Dennis Zhou's avatar Dennis Zhou Committed by David Sterba
Browse files

btrfs: add compression interface in (get/put)_workspace 



There are two levels of workspace management. First, alloc()/free()
which are responsible for actually creating and destroy workspaces.
Second, at a higher level, get()/put() which is the compression code
asking for a workspace from a workspace_manager.

The compression code shouldn't really care how it gets a workspace, but
that it got a workspace. This adds get_workspace() and put_workspace()
to be the higher level interface which is responsible for indexing into
the appropriate compression type. It also introduces
btrfs_put_workspace() and btrfs_get_workspace() to be the generic
implementations of the higher interface.

Reviewed-by: default avatarJosef Bacik <josef@toxicpanda.com>
Signed-off-by: default avatarDennis Zhou <dennis@kernel.org>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 1666edab

fs/btrfs/compression.c

+34 −23
Original line number Diff line number Diff line
@@ -841,7 +841,7 @@ static void btrfs_cleanup_workspace_manager(struct workspace_manager *wsman) 
 * Preallocation makes a forward progress guarantees and we do not return

 * errors.

 */

static struct list_head *find_workspace(int type)

static struct list_head *btrfs_get_workspace(struct workspace_manager *wsman)

{

	struct list_head *workspace;

	int cpus = num_online_cpus();
@@ -852,11 +852,11 @@ static struct list_head *find_workspace(int type) 
	wait_queue_head_t *ws_wait;

	int *free_ws;



	idle_ws	 = &wsm[type].idle_ws;

	ws_lock	 = &wsm[type].ws_lock;

	total_ws = &wsm[type].total_ws;

	ws_wait	 = &wsm[type].ws_wait;

	free_ws	 = &wsm[type].free_ws;

	idle_ws	 = &wsman->idle_ws;

	ws_lock	 = &wsman->ws_lock;

	total_ws = &wsman->total_ws;

	ws_wait	 = &wsman->ws_wait;

	free_ws	 = &wsman->free_ws;



again:

	spin_lock(ws_lock);
@@ -887,7 +887,7 @@ again: 
	 * context of btrfs_compress_bio/btrfs_compress_pages

	 */

	nofs_flag = memalloc_nofs_save();

	workspace = wsm[type].ops->alloc_workspace();

	workspace = wsman->ops->alloc_workspace();

	memalloc_nofs_restore(nofs_flag);



	if (IS_ERR(workspace)) {
@@ -918,11 +918,17 @@ again: 
	return workspace;

}



static struct list_head *get_workspace(int type)

{

	return btrfs_get_workspace(&wsm[type]);

}



/*

 * put a workspace struct back on the list or free it if we have enough

 * idle ones sitting around

 */

static void free_workspace(int type, struct list_head *workspace)

static void btrfs_put_workspace(struct workspace_manager *wsman,

				struct list_head *ws)

{

	struct list_head *idle_ws;

	spinlock_t *ws_lock;
@@ -930,27 +936,32 @@ static void free_workspace(int type, struct list_head *workspace) 
	wait_queue_head_t *ws_wait;

	int *free_ws;



	idle_ws	 = &wsm[type].idle_ws;

	ws_lock	 = &wsm[type].ws_lock;

	total_ws = &wsm[type].total_ws;

	ws_wait	 = &wsm[type].ws_wait;

	free_ws	 = &wsm[type].free_ws;

	idle_ws	 = &wsman->idle_ws;

	ws_lock	 = &wsman->ws_lock;

	total_ws = &wsman->total_ws;

	ws_wait	 = &wsman->ws_wait;

	free_ws	 = &wsman->free_ws;



	spin_lock(ws_lock);

	if (*free_ws <= num_online_cpus()) {

		list_add(workspace, idle_ws);

		list_add(ws, idle_ws);

		(*free_ws)++;

		spin_unlock(ws_lock);

		goto wake;

	}

	spin_unlock(ws_lock);



	wsm[type].ops->free_workspace(workspace);

	wsman->ops->free_workspace(ws);

	atomic_dec(total_ws);

wake:

	cond_wake_up(ws_wait);

}



static void put_workspace(int type, struct list_head *ws)

{

	return btrfs_put_workspace(&wsm[type], ws);

}



/*

 * Given an address space and start and length, compress the bytes into @pages

 * that are allocated on demand.
@@ -984,14 +995,14 @@ int btrfs_compress_pages(unsigned int type_level, struct address_space *mapping, 
	struct list_head *workspace;

	int ret;



	workspace = find_workspace(type);

	workspace = get_workspace(type);



	btrfs_compress_op[type]->set_level(workspace, type_level);

	ret = btrfs_compress_op[type]->compress_pages(workspace, mapping,

						      start, pages,

						      out_pages,

						      total_in, total_out);

	free_workspace(type, workspace);

	put_workspace(type, workspace);

	return ret;

}
@@ -1015,9 +1026,9 @@ static int btrfs_decompress_bio(struct compressed_bio *cb) 
	int ret;

	int type = cb->compress_type;



	workspace = find_workspace(type);

	workspace = get_workspace(type);

	ret = btrfs_compress_op[type]->decompress_bio(workspace, cb);

	free_workspace(type, workspace);

	put_workspace(type, workspace);



	return ret;

}
@@ -1033,13 +1044,13 @@ int btrfs_decompress(int type, unsigned char *data_in, struct page *dest_page, 
	struct list_head *workspace;

	int ret;



	workspace = find_workspace(type);

	workspace = get_workspace(type);



	ret = btrfs_compress_op[type]->decompress(workspace, data_in,

						  dest_page, start_byte,

						  srclen, destlen);



	free_workspace(type, workspace);

	put_workspace(type, workspace);

	return ret;

}
@@ -1467,7 +1478,7 @@ static void heuristic_collect_sample(struct inode *inode, u64 start, u64 end, 
 */

int btrfs_compress_heuristic(struct inode *inode, u64 start, u64 end)

{

	struct list_head *ws_list = find_workspace(0);

	struct list_head *ws_list = get_workspace(0);

	struct heuristic_ws *ws;

	u32 i;

	u8 byte;
@@ -1536,7 +1547,7 @@ int btrfs_compress_heuristic(struct inode *inode, u64 start, u64 end) 
	}



out:

	free_workspace(0, ws_list);

	put_workspace(0, ws_list);

	return ret;

}

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