wait_iff_congested

Name:wait_iff_congested - Conditionally wait for a backing_dev to become uncongested or a pgdat to complete writes*@sync: SYNC or ASYNC IO*@timeout: timeout in jiffies* In the event of a congested backing_dev (any backing_dev) this waits* for up to @timeout

Proto:long wait_iff_congested(int sync, long timeout)

Type:long

Parameter:

Type	Parameter	Name
int	sync
long	timeout

1119

start = jiffies

1120

DEFINE_WAIT(wait)

1121

wqh = congestion_wqh[sync]

1127

If atomic_read( & nr_wb_congested[sync]) == 0 Then

1128

1131

ret = timeout - jiffies - start

1132

If ret < 0 Then ret = 0

1135

Go to out

1139

Note: we use "set_current_state()" _after_ the wait-queue add,* because we need a memory barrier there on SMP, so that any* wake-function that tests for the wait-queue being active* will be guaranteed to see waitqueue addition _or_ subsequent

1140

ret = This task is about to go to sleep on IO. Increment rq->nr_iowait so* that process accounting knows that this is a task in IO wait state.

1141

sh_wait - clean up after waiting in a queue*@wq_head: waitqueue waited on*@wq_entry: wait descriptor* Sets current thread back to running state and removes* the wait descriptor from the given waitqueue if still* queued.

1143

out :

1144

trace_writeback_wait_iff_congested(jiffies_to_usecs(timeout), jiffies_to_usecs(jiffies - start))

1147

Return ret

**Caller**
Name	Describe
shrink_node

Source code conversion tool public plug-in interface	X
Support c/c++/esqlc/java Oracle/Informix/Mysql Plug-in can realize: logical Report Code generation and batch code conversion