[PATCH 040/102] xfs: remove log space waitqueues

Dave Chinner
2012-08-23T05:03:33Z

From: Christoph Hellwig <hch@infradead.org>

Upstream commit: 14a7235fba4302a82d61150eda92ec90d3ae9cfb

The tic->t_wait waitqueues can never have more than a single waiter
on them, so we can easily replace them with a task_struct pointer
and wake_up_process.

Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
---
fs/xfs/xfs_log.c | 24 +++++++++++++++---------
fs/xfs/xfs_log_priv.h | 2 +-
2 files changed, 16 insertions(+), 10 deletions(-)

diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index d299223..fc2b84b 100644
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -169,7 +169,7 @@ xlog_reserveq_wake(
*free_bytes -= need_bytes;

trace_xfs_log_grant_wake_up(log, tic);
- wake_up(&tic->t_wait);
+ wake_up_process(tic->t_task);
}

return true;
@@ -193,7 +193,7 @@ xlog_writeq_wake(
*free_bytes -= need_bytes;

trace_xfs_log_regrant_write_wake_up(log, tic);
- wake_up(&tic->t_wait);
+ wake_up_process(tic->t_task);
}

return true;
@@ -212,10 +212,13 @@ xlog_reserveq_wait(
goto shutdown;
xlog_grant_push_ail(log, need_bytes);

+ __set_current_state(TASK_UNINTERRUPTIBLE);
+ spin_unlock(&log->l_grant_reserve_lock);
+
XFS_STATS_INC(xs_sleep_logspace);
- trace_xfs_log_grant_sleep(log, tic);

- xlog_wait(&tic->t_wait, &log->l_grant_reserve_lock);
+ trace_xfs_log_grant_sleep(log, tic);
+ schedule();
trace_xfs_log_grant_wake(log, tic);

spin_lock(&log->l_grant_reserve_lock);
@@ -243,10 +246,13 @@ xlog_writeq_wait(
goto shutdown;
xlog_grant_push_ail(log, need_bytes);

+ __set_current_state(TASK_UNINTERRUPTIBLE);
+ spin_unlock(&log->l_grant_write_lock);
+
XFS_STATS_INC(xs_sleep_logspace);
- trace_xfs_log_regrant_write_sleep(log, tic);

- xlog_wait(&tic->t_wait, &log->l_grant_write_lock);
+ trace_xfs_log_regrant_write_sleep(log, tic);
+ schedule();
trace_xfs_log_regrant_write_wake(log, tic);

spin_lock(&log->l_grant_write_lock);
@@ -3327,6 +3333,7 @@ xlog_ticket_alloc(
}

atomic_set(&tic->t_ref, 1);
+ tic->t_task = current;
INIT_LIST_HEAD(&tic->t_queue);
tic->t_unit_res = unit_bytes;
tic->t_curr_res = unit_bytes;
@@ -3338,7 +3345,6 @@ xlog_ticket_alloc(
tic->t_trans_type = 0;
if (xflags & XFS_LOG_PERM_RESERV)
tic->t_flags |= XLOG_TIC_PERM_RESERV;
- init_waitqueue_head(&tic->t_wait);

xlog_tic_reset_res(tic);

@@ -3666,12 +3672,12 @@ xfs_log_force_umount(
*/
spin_lock(&log->l_grant_reserve_lock);
list_for_each_entry(tic, &log->l_reserveq, t_queue)
- wake_up(&tic->t_wait);
+ wake_up_process(tic->t_task);
spin_unlock(&log->l_grant_reserve_lock);

spin_lock(&log->l_grant_write_lock);
list_for_each_entry(tic, &log->l_writeq, t_queue)
- wake_up(&tic->t_wait);
+ wake_up_process(tic->t_task);
spin_unlock(&log->l_grant_write_lock);

if (!(log->l_iclog->ic_state & XLOG_STATE_IOERROR)) {
diff --git a/fs/xfs/xfs_log_priv.h b/fs/xfs/xfs_log_priv.h
index 785905e..d8c5e47 100644
--- a/fs/xfs/xfs_log_priv.h
+++ b/fs/xfs/xfs_log_priv.h
@@ -239,8 +239,8 @@ typedef struct xlog_res {
} xlog_res_t;

typedef struct xlog_ticket {
- wait_queue_head_t t_wait; /* ticket wait queue */
struct list_head t_queue; /* reserve/write queue */
+ struct task_struct *t_task; /* task that owns this ticket */
xlog_tid_t t_tid; /* transaction identifier : 4 */
atomic_t t_ref; /* ticket reference count : 4 */
int t_curr_res; /* current reservation in bytes : 4 */