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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 <nefelim4ag@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ coding style fixes ]
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Timofey Titovets 2017-09-28 17:33:36 +03:00 committed by David Sterba
parent ddfae63cc8
commit 4e439a0b18
1 changed files with 121 additions and 18 deletions
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139
fs/btrfs/compression.c
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@ -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;
}