writeback: add comments to bdi_work structure

And document its retriever, get_next_work_item().

Acked-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This commit is contained in:
Jens Axboe 2009-09-15 20:04:57 +02:00
parent ce5f8e7795
commit 8010c3b634

View file

@ -49,15 +49,15 @@ struct wb_writeback_args {
* Work items for the bdi_writeback threads
*/
struct bdi_work {
struct list_head list;
struct rcu_head rcu_head;
struct list_head list; /* pending work list */
struct rcu_head rcu_head; /* for RCU free/clear of work */
unsigned long seen;
atomic_t pending;
unsigned long seen; /* threads that have seen this work */
atomic_t pending; /* number of threads still to do work */
struct wb_writeback_args args;
struct wb_writeback_args args; /* writeback arguments */
unsigned long state;
unsigned long state; /* flag bits, see WS_* */
};
enum {
@ -758,7 +758,11 @@ static long wb_writeback(struct bdi_writeback *wb,
/*
* Return the next bdi_work struct that hasn't been processed by this
* wb thread yet
* wb thread yet. ->seen is initially set for each thread that exists
* for this device, when a thread first notices a piece of work it
* clears its bit. Depending on writeback type, the thread will notify
* completion on either receiving the work (WB_SYNC_NONE) or after
* it is done (WB_SYNC_ALL).
*/
static struct bdi_work *get_next_work_item(struct backing_dev_info *bdi,
struct bdi_writeback *wb)