btrfs: plumb level through the compression interface

Zlib compression supports multiple levels, but doesn't require changing
in how a workspace itself is created and managed. Zstd introduces a
different memory requirement such that higher levels of compression
require more memory.

This requires changes in how the alloc()/get() methods work for zstd.
This pach plumbs compression level through the interface as a parameter
in preparation for zstd compression levels.  This gives the compression
types opportunity to create/manage based on the compression level.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Dennis Zhou <dennis@kernel.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/compression.c

@@ -742,9 +742,9 @@ static void heuristic_cleanup_workspace_manager(void)
 	btrfs_cleanup_workspace_manager(&heuristic_wsm);
 }
 
-static struct list_head *heuristic_get_workspace(void)
+static struct list_head *heuristic_get_workspace(unsigned int level)
 {
-	return btrfs_get_workspace(&heuristic_wsm);
+	return btrfs_get_workspace(&heuristic_wsm, level);
 }
 
 static void heuristic_put_workspace(struct list_head *ws)
@@ -764,7 +764,7 @@ static void free_heuristic_ws(struct list_head *ws)
 	kfree(workspace);
 }
 
-static struct list_head *alloc_heuristic_ws(void)
+static struct list_head *alloc_heuristic_ws(unsigned int level)
 {
 	struct heuristic_ws *ws;
 
@@ -824,7 +824,7 @@ void btrfs_init_workspace_manager(struct workspace_manager *wsm,
 	 * Preallocate one workspace for each compression type so we can
 	 * guarantee forward progress in the worst case
 	 */
-	workspace = wsm->ops->alloc_workspace();
+	workspace = wsm->ops->alloc_workspace(0);
 	if (IS_ERR(workspace)) {
 		pr_warn(
 	"BTRFS: cannot preallocate compression workspace, will try later\n");
@@ -853,7 +853,8 @@ void btrfs_cleanup_workspace_manager(struct workspace_manager *wsman)
  * Preallocation makes a forward progress guarantees and we do not return
  * errors.
  */
-struct list_head *btrfs_get_workspace(struct workspace_manager *wsm)
+struct list_head *btrfs_get_workspace(struct workspace_manager *wsm,
+				      unsigned int level)
 {
 	struct list_head *workspace;
 	int cpus = num_online_cpus();
@@ -899,7 +900,7 @@ again:
 	 * context of btrfs_compress_bio/btrfs_compress_pages
 	 */
 	nofs_flag = memalloc_nofs_save();
-	workspace = wsm->ops->alloc_workspace();
+	workspace = wsm->ops->alloc_workspace(level);
 	memalloc_nofs_restore(nofs_flag);
 
 	if (IS_ERR(workspace)) {
@@ -930,9 +931,9 @@ again:
 	return workspace;
 }
 
-static struct list_head *get_workspace(int type)
+static struct list_head *get_workspace(int type, int level)
 {
-	return btrfs_compress_op[type]->get_workspace();
+	return btrfs_compress_op[type]->get_workspace(level);
 }
 
 /*
@@ -1003,12 +1004,13 @@ int btrfs_compress_pages(unsigned int type_level, struct address_space *mapping,
 			 unsigned long *total_out)
 {
 	int type = btrfs_compress_type(type_level);
+	int level = btrfs_compress_level(type_level);
 	struct list_head *workspace;
 	int ret;
 
-	workspace = get_workspace(type);
+	workspace = get_workspace(type, level);
 
-	btrfs_compress_op[type]->set_level(workspace, type_level);
+	btrfs_compress_op[type]->set_level(workspace, level);
 	ret = btrfs_compress_op[type]->compress_pages(workspace, mapping,
 						      start, pages,
 						      out_pages,
@@ -1037,7 +1039,7 @@ static int btrfs_decompress_bio(struct compressed_bio *cb)
 	int ret;
 	int type = cb->compress_type;
 
-	workspace = get_workspace(type);
+	workspace = get_workspace(type, 0);
 	ret = btrfs_compress_op[type]->decompress_bio(workspace, cb);
 	put_workspace(type, workspace);
 
@@ -1055,13 +1057,12 @@ int btrfs_decompress(int type, unsigned char *data_in, struct page *dest_page,
 	struct list_head *workspace;
 	int ret;
 
-	workspace = get_workspace(type);
+	workspace = get_workspace(type, 0);
-
 	ret = btrfs_compress_op[type]->decompress(workspace, data_in,
 						  dest_page, start_byte,
 						  srclen, destlen);
-
 	put_workspace(type, workspace);
+
 	return ret;
 }
 
@@ -1489,7 +1490,7 @@ 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 = get_workspace(0);
+	struct list_head *ws_list = get_workspace(0, 0);
 	struct heuristic_ws *ws;
 	u32 i;
 	u8 byte;

fs/btrfs/compression.h

@@ -121,7 +121,8 @@ struct workspace_manager {
 
 void btrfs_init_workspace_manager(struct workspace_manager *wsm,
 				  const struct btrfs_compress_op *ops);
-struct list_head *btrfs_get_workspace(struct workspace_manager *wsm);
+struct list_head *btrfs_get_workspace(struct workspace_manager *wsm,
+				      unsigned int level);
 void btrfs_put_workspace(struct workspace_manager *wsm, struct list_head *ws);
 void btrfs_cleanup_workspace_manager(struct workspace_manager *wsm);
 
@@ -130,11 +131,11 @@ struct btrfs_compress_op {
 
 	void (*cleanup_workspace_manager)(void);
 
-	struct list_head *(*get_workspace)(void);
+	struct list_head *(*get_workspace)(unsigned int level);
 
 	void (*put_workspace)(struct list_head *ws);
 
-	struct list_head *(*alloc_workspace)(void);
+	struct list_head *(*alloc_workspace)(unsigned int level);
 
 	void (*free_workspace)(struct list_head *workspace);
 

fs/btrfs/lzo.c

@@ -73,9 +73,9 @@ static void lzo_cleanup_workspace_manager(void)
 	btrfs_cleanup_workspace_manager(&wsm);
 }
 
-static struct list_head *lzo_get_workspace(void)
+static struct list_head *lzo_get_workspace(unsigned int level)
 {
-	return btrfs_get_workspace(&wsm);
+	return btrfs_get_workspace(&wsm, level);
 }
 
 static void lzo_put_workspace(struct list_head *ws)
@@ -93,7 +93,7 @@ static void lzo_free_workspace(struct list_head *ws)
 	kfree(workspace);
 }
 
-static struct list_head *lzo_alloc_workspace(void)
+static struct list_head *lzo_alloc_workspace(unsigned int level)
 {
 	struct workspace *workspace;
 

fs/btrfs/zlib.c

@@ -39,9 +39,9 @@ static void zlib_cleanup_workspace_manager(void)
 	btrfs_cleanup_workspace_manager(&wsm);
 }
 
-static struct list_head *zlib_get_workspace(void)
+static struct list_head *zlib_get_workspace(unsigned int level)
 {
-	return btrfs_get_workspace(&wsm);
+	return btrfs_get_workspace(&wsm, level);
 }
 
 static void zlib_put_workspace(struct list_head *ws)
@@ -58,7 +58,7 @@ static void zlib_free_workspace(struct list_head *ws)
 	kfree(workspace);
 }
 
-static struct list_head *zlib_alloc_workspace(void)
+static struct list_head *zlib_alloc_workspace(unsigned int level)
 {
 	struct workspace *workspace;
 	int workspacesize;
@@ -70,6 +70,7 @@ static struct list_head *zlib_alloc_workspace(void)
 	workspacesize = max(zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL),
 			zlib_inflate_workspacesize());
 	workspace->strm.workspace = kvmalloc(workspacesize, GFP_KERNEL);
+	workspace->level = level;
 	workspace->buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
 	if (!workspace->strm.workspace || !workspace->buf)
 		goto fail;

fs/btrfs/zstd.c

@@ -53,9 +53,9 @@ static void zstd_cleanup_workspace_manager(void)
 	btrfs_cleanup_workspace_manager(&wsm);
 }
 
-static struct list_head *zstd_get_workspace(void)
+static struct list_head *zstd_get_workspace(unsigned int level)
 {
-	return btrfs_get_workspace(&wsm);
+	return btrfs_get_workspace(&wsm, level);
 }
 
 static void zstd_put_workspace(struct list_head *ws)
@@ -72,7 +72,7 @@ static void zstd_free_workspace(struct list_head *ws)
 	kfree(workspace);
 }
 
-static struct list_head *zstd_alloc_workspace(void)
+static struct list_head *zstd_alloc_workspace(unsigned int level)
 {
 	ZSTD_parameters params =
 			zstd_get_btrfs_parameters(ZSTD_BTRFS_MAX_INPUT);