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-rw-r--r--block/blk-wbt.c89
1 files changed, 70 insertions, 19 deletions
diff --git a/block/blk-wbt.c b/block/blk-wbt.c
index 84507d3e9a98..8e20a0677dcf 100644
--- a/block/blk-wbt.c
+++ b/block/blk-wbt.c
@@ -123,16 +123,11 @@ static void rwb_wake_all(struct rq_wb *rwb)
}
}
-static void __wbt_done(struct rq_qos *rqos, enum wbt_flags wb_acct)
+static void wbt_rqw_done(struct rq_wb *rwb, struct rq_wait *rqw,
+ enum wbt_flags wb_acct)
{
- struct rq_wb *rwb = RQWB(rqos);
- struct rq_wait *rqw;
int inflight, limit;
- if (!(wb_acct & WBT_TRACKED))
- return;
-
- rqw = get_rq_wait(rwb, wb_acct);
inflight = atomic_dec_return(&rqw->inflight);
/*
@@ -166,10 +161,22 @@ static void __wbt_done(struct rq_qos *rqos, enum wbt_flags wb_acct)
int diff = limit - inflight;
if (!inflight || diff >= rwb->wb_background / 2)
- wake_up(&rqw->wait);
+ wake_up_all(&rqw->wait);
}
}
+static void __wbt_done(struct rq_qos *rqos, enum wbt_flags wb_acct)
+{
+ struct rq_wb *rwb = RQWB(rqos);
+ struct rq_wait *rqw;
+
+ if (!(wb_acct & WBT_TRACKED))
+ return;
+
+ rqw = get_rq_wait(rwb, wb_acct);
+ wbt_rqw_done(rwb, rqw, wb_acct);
+}
+
/*
* Called on completion of a request. Note that it's also called when
* a request is merged, when the request gets freed.
@@ -481,6 +488,34 @@ static inline unsigned int get_limit(struct rq_wb *rwb, unsigned long rw)
return limit;
}
+struct wbt_wait_data {
+ struct wait_queue_entry wq;
+ struct task_struct *task;
+ struct rq_wb *rwb;
+ struct rq_wait *rqw;
+ unsigned long rw;
+ bool got_token;
+};
+
+static int wbt_wake_function(struct wait_queue_entry *curr, unsigned int mode,
+ int wake_flags, void *key)
+{
+ struct wbt_wait_data *data = container_of(curr, struct wbt_wait_data,
+ wq);
+
+ /*
+ * If we fail to get a budget, return -1 to interrupt the wake up
+ * loop in __wake_up_common.
+ */
+ if (!rq_wait_inc_below(data->rqw, get_limit(data->rwb, data->rw)))
+ return -1;
+
+ data->got_token = true;
+ list_del_init(&curr->entry);
+ wake_up_process(data->task);
+ return 1;
+}
+
/*
* Block if we will exceed our limit, or if we are currently waiting for
* the timer to kick off queuing again.
@@ -491,19 +526,40 @@ static void __wbt_wait(struct rq_wb *rwb, enum wbt_flags wb_acct,
__acquires(lock)
{
struct rq_wait *rqw = get_rq_wait(rwb, wb_acct);
- DECLARE_WAITQUEUE(wait, current);
+ struct wbt_wait_data data = {
+ .wq = {
+ .func = wbt_wake_function,
+ .entry = LIST_HEAD_INIT(data.wq.entry),
+ },
+ .task = current,
+ .rwb = rwb,
+ .rqw = rqw,
+ .rw = rw,
+ };
bool has_sleeper;
has_sleeper = wq_has_sleeper(&rqw->wait);
if (!has_sleeper && rq_wait_inc_below(rqw, get_limit(rwb, rw)))
return;
- add_wait_queue_exclusive(&rqw->wait, &wait);
+ prepare_to_wait_exclusive(&rqw->wait, &data.wq, TASK_UNINTERRUPTIBLE);
do {
- set_current_state(TASK_UNINTERRUPTIBLE);
+ if (data.got_token)
+ break;
- if (!has_sleeper && rq_wait_inc_below(rqw, get_limit(rwb, rw)))
+ if (!has_sleeper &&
+ rq_wait_inc_below(rqw, get_limit(rwb, rw))) {
+ finish_wait(&rqw->wait, &data.wq);
+
+ /*
+ * We raced with wbt_wake_function() getting a token,
+ * which means we now have two. Put our local token
+ * and wake anyone else potentially waiting for one.
+ */
+ if (data.got_token)
+ wbt_rqw_done(rwb, rqw, wb_acct);
break;
+ }
if (lock) {
spin_unlock_irq(lock);
@@ -511,11 +567,11 @@ static void __wbt_wait(struct rq_wb *rwb, enum wbt_flags wb_acct,
spin_lock_irq(lock);
} else
io_schedule();
+
has_sleeper = false;
} while (1);
- __set_current_state(TASK_RUNNING);
- remove_wait_queue(&rqw->wait, &wait);
+ finish_wait(&rqw->wait, &data.wq);
}
static inline bool wbt_should_throttle(struct rq_wb *rwb, struct bio *bio)
@@ -580,11 +636,6 @@ static void wbt_wait(struct rq_qos *rqos, struct bio *bio, spinlock_t *lock)
return;
}
- if (current_is_kswapd())
- flags |= WBT_KSWAPD;
- if (bio_op(bio) == REQ_OP_DISCARD)
- flags |= WBT_DISCARD;
-
__wbt_wait(rwb, flags, bio->bi_opf, lock);
if (!blk_stat_is_active(rwb->cb))