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| author | Jens Axboe <jens.axboe@oracle.com> | 2009-09-15 20:04:57 +0200 |
|---|---|---|
| committer | Jens Axboe <jens.axboe@oracle.com> | 2009-09-16 15:18:52 +0200 |
| commit | 8010c3b6349b407f8f11b3f4d7e9f94cb00fe528 (patch) | |
| tree | eecf594bec286f582c0b9709a87a0edb82dc034b | |
| parent | ce5f8e7795195edb6f84f74aa9d72e739df38486 (diff) | |
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>
| -rw-r--r-- | fs/fs-writeback.c | 18 |
1 files changed, 11 insertions, 7 deletions
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 5887328b5a06..55f0d4e51b59 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -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) |