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authorDavid Sterba <dsterba@suse.com>2016-04-27 02:15:15 +0200
committerDavid Sterba <dsterba@suse.com>2016-05-10 09:46:08 +0200
commit6ac10a6ac2b11ada24580cc76dcd0c182061c576 (patch)
tree2027483cee168cf52da50e5c729b0721f2d21016 /fs/btrfs
parent8eb0dfdbda3f56bf7d248ed87fcc383df114ecbb (diff)
btrfs: rename and document compression workspace members
The names are confusing, pick more fitting names and add comments. Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs')
-rw-r--r--fs/btrfs/compression.c35
1 files changed, 19 insertions, 16 deletions
diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index ff61a41ac90b..4d5cd9624bb3 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -743,8 +743,11 @@ out:
static struct {
struct list_head idle_ws;
spinlock_t ws_lock;
- int num_ws;
- atomic_t alloc_ws;
+ /* Number of free workspaces */
+ int free_ws;
+ /* Total number of allocated workspaces */
+ atomic_t total_ws;
+ /* Waiters for a free workspace */
wait_queue_head_t ws_wait;
} btrfs_comp_ws[BTRFS_COMPRESS_TYPES];
@@ -760,7 +763,7 @@ void __init btrfs_init_compress(void)
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].alloc_ws, 0);
+ atomic_set(&btrfs_comp_ws[i].total_ws, 0);
init_waitqueue_head(&btrfs_comp_ws[i].ws_wait);
}
}
@@ -777,35 +780,35 @@ static struct list_head *find_workspace(int type)
struct list_head *idle_ws = &btrfs_comp_ws[idx].idle_ws;
spinlock_t *ws_lock = &btrfs_comp_ws[idx].ws_lock;
- atomic_t *alloc_ws = &btrfs_comp_ws[idx].alloc_ws;
+ atomic_t *total_ws = &btrfs_comp_ws[idx].total_ws;
wait_queue_head_t *ws_wait = &btrfs_comp_ws[idx].ws_wait;
- int *num_ws = &btrfs_comp_ws[idx].num_ws;
+ int *free_ws = &btrfs_comp_ws[idx].free_ws;
again:
spin_lock(ws_lock);
if (!list_empty(idle_ws)) {
workspace = idle_ws->next;
list_del(workspace);
- (*num_ws)--;
+ (*free_ws)--;
spin_unlock(ws_lock);
return workspace;
}
- if (atomic_read(alloc_ws) > cpus) {
+ if (atomic_read(total_ws) > cpus) {
DEFINE_WAIT(wait);
spin_unlock(ws_lock);
prepare_to_wait(ws_wait, &wait, TASK_UNINTERRUPTIBLE);
- if (atomic_read(alloc_ws) > cpus && !*num_ws)
+ if (atomic_read(total_ws) > cpus && !*free_ws)
schedule();
finish_wait(ws_wait, &wait);
goto again;
}
- atomic_inc(alloc_ws);
+ atomic_inc(total_ws);
spin_unlock(ws_lock);
workspace = btrfs_compress_op[idx]->alloc_workspace();
if (IS_ERR(workspace)) {
- atomic_dec(alloc_ws);
+ atomic_dec(total_ws);
wake_up(ws_wait);
}
return workspace;
@@ -820,21 +823,21 @@ static void free_workspace(int type, struct list_head *workspace)
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 *alloc_ws = &btrfs_comp_ws[idx].alloc_ws;
+ atomic_t *total_ws = &btrfs_comp_ws[idx].total_ws;
wait_queue_head_t *ws_wait = &btrfs_comp_ws[idx].ws_wait;
- int *num_ws = &btrfs_comp_ws[idx].num_ws;
+ int *free_ws = &btrfs_comp_ws[idx].free_ws;
spin_lock(ws_lock);
- if (*num_ws < num_online_cpus()) {
+ if (*free_ws < num_online_cpus()) {
list_add(workspace, idle_ws);
- (*num_ws)++;
+ (*free_ws)++;
spin_unlock(ws_lock);
goto wake;
}
spin_unlock(ws_lock);
btrfs_compress_op[idx]->free_workspace(workspace);
- atomic_dec(alloc_ws);
+ atomic_dec(total_ws);
wake:
/*
* Make sure counter is updated before we wake up waiters.
@@ -857,7 +860,7 @@ static void free_workspaces(void)
workspace = btrfs_comp_ws[i].idle_ws.next;
list_del(workspace);
btrfs_compress_op[i]->free_workspace(workspace);
- atomic_dec(&btrfs_comp_ws[i].alloc_ws);
+ atomic_dec(&btrfs_comp_ws[i].total_ws);
}
}
}