btrfs: make zstd memory requirements monotonic (d3c6ab75) · Commits · 戴 / test

fs/btrfs/zstd.c

+33 −5

Original line number	Diff line number	Diff line
		@@ -20,6 +20,7 @@
		#define ZSTD_BTRFS_MAX_WINDOWLOG 17
		#define ZSTD_BTRFS_MAX_INPUT (1 << ZSTD_BTRFS_MAX_WINDOWLOG)
		#define ZSTD_BTRFS_DEFAULT_LEVEL 3
		#define ZSTD_BTRFS_MAX_LEVEL 15

		static ZSTD_parameters zstd_get_btrfs_parameters(unsigned int level,
		size_t src_len)
		@@ -44,8 +45,39 @@ struct workspace {

		static struct workspace_manager wsm;

		static size_t zstd_ws_mem_sizes[ZSTD_BTRFS_MAX_LEVEL];

		/*
		* zstd_calc_ws_mem_sizes - calculate monotonic memory bounds
		*
		* It is possible based on the level configurations that a higher level
		* workspace uses less memory than a lower level workspace. In order to reuse
		* workspaces, this must be made a monotonic relationship. This precomputes
		* the required memory for each level and enforces the monotonicity between
		* level and memory required.
		*/
		static void zstd_calc_ws_mem_sizes(void)
		{
		size_t max_size = 0;
		unsigned int level;

		for (level = 1; level <= ZSTD_BTRFS_MAX_LEVEL; level++) {
		ZSTD_parameters params =
		zstd_get_btrfs_parameters(level, ZSTD_BTRFS_MAX_INPUT);
		size_t level_size =
		max_t(size_t,
		ZSTD_CStreamWorkspaceBound(params.cParams),
		ZSTD_DStreamWorkspaceBound(ZSTD_BTRFS_MAX_INPUT));

		max_size = max_t(size_t, max_size, level_size);
		zstd_ws_mem_sizes[level - 1] = max_size;
		}
		}

		static void zstd_init_workspace_manager(void)
		{
		zstd_calc_ws_mem_sizes();

		btrfs_init_workspace_manager(&wsm, &btrfs_zstd_compress);
		}

		@@ -80,17 +112,13 @@ static void zstd_free_workspace(struct list_head *ws)

		static struct list_head *zstd_alloc_workspace(unsigned int level)
		{
		ZSTD_parameters params =
		zstd_get_btrfs_parameters(level, ZSTD_BTRFS_MAX_INPUT);
		struct workspace *workspace;

		workspace = kzalloc(sizeof(*workspace), GFP_KERNEL);
		if (!workspace)
		return ERR_PTR(-ENOMEM);

		workspace->size = max_t(size_t,
		ZSTD_CStreamWorkspaceBound(params.cParams),
		ZSTD_DStreamWorkspaceBound(ZSTD_BTRFS_MAX_INPUT));
		workspace->size = zstd_ws_mem_sizes[level - 1];
		workspace->mem = kvmalloc(workspace->size, GFP_KERNEL);
		workspace->buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
		if (!workspace->mem \|\| !workspace->buf)

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