From 4e439a0b184f014a5833fa468af36cc9f59b8fb1 Mon Sep 17 00:00:00 2001 From: Timofey Titovets Date: Thu, 28 Sep 2017 17:33:36 +0300 Subject: [PATCH] Btrfs: compression: separate heuristic/compression workspaces Compression heuristic itself is not a compression type, as current infrastructure provides workspaces for several compression types, it's difficult to just add heuristic workspace. Just refactor the code to support compression/heuristic workspaces with maximum code sharing and minimum changes in it. Signed-off-by: Timofey Titovets Reviewed-by: David Sterba [ coding style fixes ] Signed-off-by: David Sterba --- fs/btrfs/compression.c | 139 +++++++++++++++++++++++++++++++++++------ 1 file changed, 121 insertions(+), 18 deletions(-) diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c index 083f9c485875..b155542c5e6b 100644 --- a/fs/btrfs/compression.c +++ b/fs/btrfs/compression.c @@ -707,7 +707,34 @@ blk_status_t btrfs_submit_compressed_read(struct inode *inode, struct bio *bio, return ret; } -static struct { + +struct heuristic_ws { + struct list_head list; +}; + +static void free_heuristic_ws(struct list_head *ws) +{ + struct heuristic_ws *workspace; + + workspace = list_entry(ws, struct heuristic_ws, list); + + kfree(workspace); +} + +static struct list_head *alloc_heuristic_ws(void) +{ + struct heuristic_ws *ws; + + ws = kzalloc(sizeof(*ws), GFP_KERNEL); + if (!ws) + return ERR_PTR(-ENOMEM); + + INIT_LIST_HEAD(&ws->list); + + return &ws->list; +} + +struct workspaces_list { struct list_head idle_ws; spinlock_t ws_lock; /* Number of free workspaces */ @@ -716,7 +743,11 @@ static struct { atomic_t total_ws; /* Waiters for a free workspace */ wait_queue_head_t ws_wait; -} btrfs_comp_ws[BTRFS_COMPRESS_TYPES]; +}; + +static struct workspaces_list btrfs_comp_ws[BTRFS_COMPRESS_TYPES]; + +static struct workspaces_list btrfs_heuristic_ws; static const struct btrfs_compress_op * const btrfs_compress_op[] = { &btrfs_zlib_compress, @@ -726,11 +757,25 @@ static const struct btrfs_compress_op * const btrfs_compress_op[] = { void __init btrfs_init_compress(void) { + struct list_head *workspace; int i; - for (i = 0; i < BTRFS_COMPRESS_TYPES; i++) { - struct list_head *workspace; + 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(&btrfs_comp_ws[i].idle_ws); spin_lock_init(&btrfs_comp_ws[i].ws_lock); atomic_set(&btrfs_comp_ws[i].total_ws, 0); @@ -757,18 +802,32 @@ 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) +static struct list_head *__find_workspace(int type, bool heuristic) { 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; + 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 = &btrfs_comp_ws[idx].idle_ws; + ws_lock = &btrfs_comp_ws[idx].ws_lock; + total_ws = &btrfs_comp_ws[idx].total_ws; + ws_wait = &btrfs_comp_ws[idx].ws_wait; + free_ws = &btrfs_comp_ws[idx].free_ws; + } - struct list_head *idle_ws = &btrfs_comp_ws[idx].idle_ws; - spinlock_t *ws_lock = &btrfs_comp_ws[idx].ws_lock; - atomic_t *total_ws = &btrfs_comp_ws[idx].total_ws; - wait_queue_head_t *ws_wait = &btrfs_comp_ws[idx].ws_wait; - int *free_ws = &btrfs_comp_ws[idx].free_ws; again: spin_lock(ws_lock); if (!list_empty(idle_ws)) { @@ -798,7 +857,10 @@ static struct list_head *find_workspace(int type) * context of btrfs_compress_bio/btrfs_compress_pages */ nofs_flag = memalloc_nofs_save(); - workspace = btrfs_compress_op[idx]->alloc_workspace(); + if (heuristic) + workspace = alloc_heuristic_ws(); + else + workspace = btrfs_compress_op[idx]->alloc_workspace(); memalloc_nofs_restore(nofs_flag); if (IS_ERR(workspace)) { @@ -829,18 +891,38 @@ static struct list_head *find_workspace(int type) 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) +static void __free_workspace(int type, struct list_head *workspace, + bool heuristic) { int idx = type - 1; - struct list_head *idle_ws = &btrfs_comp_ws[idx].idle_ws; - spinlock_t *ws_lock = &btrfs_comp_ws[idx].ws_lock; - atomic_t *total_ws = &btrfs_comp_ws[idx].total_ws; - wait_queue_head_t *ws_wait = &btrfs_comp_ws[idx].ws_wait; - int *free_ws = &btrfs_comp_ws[idx].free_ws; + 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 = &btrfs_comp_ws[idx].idle_ws; + ws_lock = &btrfs_comp_ws[idx].ws_lock; + total_ws = &btrfs_comp_ws[idx].total_ws; + ws_wait = &btrfs_comp_ws[idx].ws_wait; + free_ws = &btrfs_comp_ws[idx].free_ws; + } spin_lock(ws_lock); if (*free_ws <= num_online_cpus()) { @@ -851,7 +933,10 @@ static void free_workspace(int type, struct list_head *workspace) } spin_unlock(ws_lock); - btrfs_compress_op[idx]->free_workspace(workspace); + if (heuristic) + free_heuristic_ws(workspace); + else + btrfs_compress_op[idx]->free_workspace(workspace); atomic_dec(total_ws); wake: /* @@ -862,6 +947,11 @@ static void free_workspace(int type, struct list_head *workspace) 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 */ @@ -870,6 +960,13 @@ 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(&btrfs_comp_ws[i].idle_ws)) { workspace = btrfs_comp_ws[i].idle_ws.next; @@ -1090,11 +1187,15 @@ int btrfs_decompress_buf2page(const char *buf, unsigned long buf_start, */ int btrfs_compress_heuristic(struct inode *inode, u64 start, u64 end) { + struct list_head *ws_list = __find_workspace(0, true); + struct heuristic_ws *ws; u64 index = start >> PAGE_SHIFT; u64 end_index = end >> PAGE_SHIFT; struct page *page; int ret = 1; + ws = list_entry(ws_list, struct heuristic_ws, list); + while (index <= end_index) { page = find_get_page(inode->i_mapping, index); kmap(page); @@ -1103,6 +1204,8 @@ int btrfs_compress_heuristic(struct inode *inode, u64 start, u64 end) index++; } + __free_workspace(0, ws_list, true); + return ret; }