Re: [PATCH 03/11] btrfs: manage heuristic workspace as index 0

From: Nikolay Borisov
Date: Tue Jan 29 2019 - 02:53:40 EST

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On 28.01.19 Ð. 23:24 Ñ., Dennis Zhou wrote:
> While the heuristic workspaces aren't really compression workspaces,
> they use the same interface for managing them. So rather than branching,
> let's just handle them once again as the index 0 compression type.
>
> Signed-off-by: Dennis Zhou <dennis@xxxxxxxxxx>

Reviewed-by: Nikolay Borisov <nborisov@xxxxxxxx> albeit one minor nit
below.
> ---
> fs/btrfs/compression.c | 107 +++++++++++-----------------------------
> fs/btrfs/compression.h | 3 +-
> fs/btrfs/ioctl.c | 2 +-
> fs/btrfs/tree-checker.c | 4 +-
> 4 files changed, 33 insertions(+), 83 deletions(-)
>
> diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
> index aced261984e2..bda7e8d2cbc7 100644
> --- a/fs/btrfs/compression.c
> +++ b/fs/btrfs/compression.c
> @@ -37,6 +37,8 @@ const char* btrfs_compress_type2str(enum btrfs_compression_type type)
> case BTRFS_COMPRESS_ZSTD:
> case BTRFS_COMPRESS_NONE:
> return btrfs_compress_types[type];
> + default:
> + return NULL;

nit: With this change...

> }
>
> return NULL;

This becomes redundant. I doubt the compiler will issue a warning since
it should be clever enough to figure we will never exit the switch()
construct.

> @@ -769,6 +771,11 @@ static struct list_head *alloc_heuristic_ws(void)
> return ERR_PTR(-ENOMEM);
> }
>
> +const struct btrfs_compress_op btrfs_heuristic_compress = {
> + .alloc_workspace = alloc_heuristic_ws,
> + .free_workspace = free_heuristic_ws,
> +};
> +
> struct workspace_manager {
> struct list_head idle_ws;
> spinlock_t ws_lock;
> @@ -782,9 +789,8 @@ struct workspace_manager {
>
> static struct workspace_manager wsm[BTRFS_COMPRESS_TYPES];
>
> -static struct workspace_manager btrfs_heuristic_ws;
> -
> static const struct btrfs_compress_op * const btrfs_compress_op[] = {
> + &btrfs_heuristic_compress,
> &btrfs_zlib_compress,
> &btrfs_lzo_compress,
> &btrfs_zstd_compress,
> @@ -795,21 +801,6 @@ void __init btrfs_init_compress(void)
> struct list_head *workspace;
> int i;
>
> - INIT_LIST_HEAD(&btrfs_heuristic_ws.idle_ws);
> - spin_lock_init(&btrfs_heuristic_ws.ws_lock);
> - atomic_set(&btrfs_heuristic_ws.total_ws, 0);
> - init_waitqueue_head(&btrfs_heuristic_ws.ws_wait);
> -
> - workspace = alloc_heuristic_ws();
> - if (IS_ERR(workspace)) {
> - pr_warn(
> - "BTRFS: cannot preallocate heuristic workspace, will try later\n");
> - } else {
> - atomic_set(&btrfs_heuristic_ws.total_ws, 1);
> - btrfs_heuristic_ws.free_ws = 1;
> - list_add(workspace, &btrfs_heuristic_ws.idle_ws);
> - }
> -
> for (i = 0; i < BTRFS_COMPRESS_TYPES; i++) {
> INIT_LIST_HEAD(&wsm[i].idle_ws);
> spin_lock_init(&wsm[i].ws_lock);
> @@ -837,11 +828,10 @@ void __init btrfs_init_compress(void)
> * Preallocation makes a forward progress guarantees and we do not return
> * errors.
> */
> -static struct list_head *__find_workspace(int type, bool heuristic)
> +static struct list_head *find_workspace(int type)
> {
> struct list_head *workspace;
> int cpus = num_online_cpus();
> - int idx = type - 1;
> unsigned nofs_flag;
> struct list_head *idle_ws;
> spinlock_t *ws_lock;
> @@ -849,19 +839,11 @@ static struct list_head *__find_workspace(int type, bool heuristic)
> wait_queue_head_t *ws_wait;
> int *free_ws;
>
> - if (heuristic) {
> - idle_ws = &btrfs_heuristic_ws.idle_ws;
> - ws_lock = &btrfs_heuristic_ws.ws_lock;
> - total_ws = &btrfs_heuristic_ws.total_ws;
> - ws_wait = &btrfs_heuristic_ws.ws_wait;
> - free_ws = &btrfs_heuristic_ws.free_ws;
> - } else {
> - idle_ws = &wsm[idx].idle_ws;
> - ws_lock = &wsm[idx].ws_lock;
> - total_ws = &wsm[idx].total_ws;
> - ws_wait = &wsm[idx].ws_wait;
> - free_ws = &wsm[idx].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;
>
> again:
> spin_lock(ws_lock);
> @@ -892,10 +874,7 @@ static struct list_head *__find_workspace(int type, bool heuristic)
> * context of btrfs_compress_bio/btrfs_compress_pages
> */
> nofs_flag = memalloc_nofs_save();
> - if (heuristic)
> - workspace = alloc_heuristic_ws();
> - else
> - workspace = btrfs_compress_op[idx]->alloc_workspace();
> + workspace = btrfs_compress_op[type]->alloc_workspace();
> memalloc_nofs_restore(nofs_flag);
>
> if (IS_ERR(workspace)) {
> @@ -926,38 +905,23 @@ static struct list_head *__find_workspace(int type, bool heuristic)
> return workspace;
> }
>
> -static struct list_head *find_workspace(int type)
> -{
> - return __find_workspace(type, false);
> -}
> -
> /*
> * 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,
> - bool heuristic)
> +static void free_workspace(int type, struct list_head *workspace)
> {
> - int idx = type - 1;
> struct list_head *idle_ws;
> spinlock_t *ws_lock;
> atomic_t *total_ws;
> wait_queue_head_t *ws_wait;
> int *free_ws;
>
> - if (heuristic) {
> - idle_ws = &btrfs_heuristic_ws.idle_ws;
> - ws_lock = &btrfs_heuristic_ws.ws_lock;
> - total_ws = &btrfs_heuristic_ws.total_ws;
> - ws_wait = &btrfs_heuristic_ws.ws_wait;
> - free_ws = &btrfs_heuristic_ws.free_ws;
> - } else {
> - idle_ws = &wsm[idx].idle_ws;
> - ws_lock = &wsm[idx].ws_lock;
> - total_ws = &wsm[idx].total_ws;
> - ws_wait = &wsm[idx].ws_wait;
> - free_ws = &wsm[idx].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;
>
> spin_lock(ws_lock);
> if (*free_ws <= num_online_cpus()) {
> @@ -968,20 +932,12 @@ static void __free_workspace(int type, struct list_head *workspace,
> }
> spin_unlock(ws_lock);
>
> - if (heuristic)
> - free_heuristic_ws(workspace);
> - else
> - btrfs_compress_op[idx]->free_workspace(workspace);
> + btrfs_compress_op[type]->free_workspace(workspace);
> atomic_dec(total_ws);
> wake:
> cond_wake_up(ws_wait);
> }
>
> -static void free_workspace(int type, struct list_head *ws)
> -{
> - return __free_workspace(type, ws, false);
> -}
> -
> /*
> * cleanup function for module exit
> */
> @@ -990,13 +946,6 @@ static void free_workspaces(void)
> struct list_head *workspace;
> int i;
>
> - while (!list_empty(&btrfs_heuristic_ws.idle_ws)) {
> - workspace = btrfs_heuristic_ws.idle_ws.next;
> - list_del(workspace);
> - free_heuristic_ws(workspace);
> - atomic_dec(&btrfs_heuristic_ws.total_ws);
> - }
> -
> for (i = 0; i < BTRFS_COMPRESS_TYPES; i++) {
> while (!list_empty(&wsm[i].idle_ws)) {
> workspace = wsm[i].idle_ws.next;
> @@ -1042,8 +991,8 @@ int btrfs_compress_pages(unsigned int type_level, struct address_space *mapping,
>
> workspace = find_workspace(type);
>
> - btrfs_compress_op[type - 1]->set_level(workspace, type_level);
> - ret = btrfs_compress_op[type-1]->compress_pages(workspace, mapping,
> + 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);
> @@ -1072,7 +1021,7 @@ static int btrfs_decompress_bio(struct compressed_bio *cb)
> int type = cb->compress_type;
>
> workspace = find_workspace(type);
> - ret = btrfs_compress_op[type - 1]->decompress_bio(workspace, cb);
> + ret = btrfs_compress_op[type]->decompress_bio(workspace, cb);
> free_workspace(type, workspace);
>
> return ret;
> @@ -1091,7 +1040,7 @@ int btrfs_decompress(int type, unsigned char *data_in, struct page *dest_page,
>
> workspace = find_workspace(type);
>
> - ret = btrfs_compress_op[type-1]->decompress(workspace, data_in,
> + ret = btrfs_compress_op[type]->decompress(workspace, data_in,
> dest_page, start_byte,
> srclen, destlen);
>
> @@ -1512,7 +1461,7 @@ 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, true);
> + struct list_head *ws_list = find_workspace(0);
> struct heuristic_ws *ws;
> u32 i;
> u8 byte;
> @@ -1581,7 +1530,7 @@ int btrfs_compress_heuristic(struct inode *inode, u64 start, u64 end)
> }
>
> out:
> - __free_workspace(0, ws_list, true);
> + free_workspace(0, ws_list);
> return ret;
> }
>
> diff --git a/fs/btrfs/compression.h b/fs/btrfs/compression.h
> index 69a9197dadc3..53a8b9e93217 100644
> --- a/fs/btrfs/compression.h
> +++ b/fs/btrfs/compression.h
> @@ -97,7 +97,7 @@ enum btrfs_compression_type {
> BTRFS_COMPRESS_ZLIB = 1,
> BTRFS_COMPRESS_LZO = 2,
> BTRFS_COMPRESS_ZSTD = 3,
> - BTRFS_COMPRESS_TYPES = 3,
> + BTRFS_COMPRESS_TYPES = 4,
> };
>
> struct btrfs_compress_op {
> @@ -125,6 +125,7 @@ struct btrfs_compress_op {
> void (*set_level)(struct list_head *ws, unsigned int type);
> };
>
> +extern const struct btrfs_compress_op btrfs_heuristic_compress;
> extern const struct btrfs_compress_op btrfs_zlib_compress;
> extern const struct btrfs_compress_op btrfs_lzo_compress;
> extern const struct btrfs_compress_op btrfs_zstd_compress;
> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> index 9c8e1734429c..20081465a451 100644
> --- a/fs/btrfs/ioctl.c
> +++ b/fs/btrfs/ioctl.c
> @@ -1410,7 +1410,7 @@ int btrfs_defrag_file(struct inode *inode, struct file *file,
> return -EINVAL;
>
> if (do_compress) {
> - if (range->compress_type > BTRFS_COMPRESS_TYPES)
> + if (range->compress_type >= BTRFS_COMPRESS_TYPES)
> return -EINVAL;
> if (range->compress_type)
> compress_type = range->compress_type;
> diff --git a/fs/btrfs/tree-checker.c b/fs/btrfs/tree-checker.c
> index a62e1e837a89..c88e146d8e99 100644
> --- a/fs/btrfs/tree-checker.c
> +++ b/fs/btrfs/tree-checker.c
> @@ -133,9 +133,9 @@ static int check_extent_data_item(struct btrfs_fs_info *fs_info,
> * Support for new compression/encryption must introduce incompat flag,
> * and must be caught in open_ctree().
> */
> - if (btrfs_file_extent_compression(leaf, fi) > BTRFS_COMPRESS_TYPES) {
> + if (btrfs_file_extent_compression(leaf, fi) >= BTRFS_COMPRESS_TYPES) {
> file_extent_err(fs_info, leaf, slot,
> - "invalid compression for file extent, have %u expect range [0, %u]",
> + "invalid compression for file extent, have %u expect range [0, %u)",
> btrfs_file_extent_compression(leaf, fi),
> BTRFS_COMPRESS_TYPES);
> return -EUCLEAN;
>

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In reply to: Dennis Zhou: "[PATCH 03/11] btrfs: manage heuristic workspace as index 0"
Next in thread: Dennis Zhou: "Re: [PATCH 03/11] btrfs: manage heuristic workspace as index 0"
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