Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 6ac10a6a authored by David Sterba's avatar David Sterba
Browse files

btrfs: rename and document compression workspace members 



The names are confusing, pick more fitting names and add comments.

Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 8eb0dfdb

fs/btrfs/compression.c

+19 −16
Original line number Diff line number Diff line
@@ -743,8 +743,11 @@ int btrfs_submit_compressed_read(struct inode *inode, struct bio *bio, 
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);

		}

	}

}