diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 399619c97567..9e24d604c59c 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -53,7 +53,6 @@ struct wb_writeback_work {
unsigned int for_background:1;
unsigned int for_sync:1; /* sync(2) WB_SYNC_ALL writeback */
unsigned int auto_free:1; /* free on completion */
- unsigned int start_all:1; /* nr_pages == 0 (all) writeback */
enum wb_reason reason; /* why was writeback initiated? */
struct list_head list; /* pending work list */
@@ -947,8 +946,6 @@ static unsigned long get_nr_dirty_pages(void)
static void wb_start_writeback(struct bdi_writeback *wb, enum wb_reason reason)
{
- struct wb_writeback_work *work;
-
if (!wb_has_dirty_io(wb))
return;
@@ -958,35 +955,14 @@ static void wb_start_writeback(struct bdi_writeback *wb, enum wb_reason reason)
* high frequency, causing pointless allocations of tons of
* work items and keeping the flusher threads busy retrieving
* that work. Ensure that we only allow one of them pending and
- * inflight at the time. It doesn't matter if we race a little
- * bit on this, so use the faster separate test/set bit variants.
+ * inflight at the time.
*/
- if (test_bit(WB_start_all, &wb->state))
+ if (test_bit(WB_start_all, &wb->state) ||
+ test_and_set_bit(WB_start_all, &wb->state))
return;
- set_bit(WB_start_all, &wb->state);
-
- /*
- * This is WB_SYNC_NONE writeback, so if allocation fails just
- * wakeup the thread for old dirty data writeback
- */
- work = kzalloc(sizeof(*work),
- GFP_NOWAIT | __GFP_NOMEMALLOC | __GFP_NOWARN);
- if (!work) {
- clear_bit(WB_start_all, &wb->state);
- trace_writeback_nowork(wb);
- wb_wakeup(wb);
- return;
- }
-
- work->sync_mode = WB_SYNC_NONE;
- work->nr_pages = wb_split_bdi_pages(wb, get_nr_dirty_pages());
- work->range_cyclic = 1;
- work->reason = reason;
- work->auto_free = 1;
- work->start_all = 1;
-
- wb_queue_work(wb, work);
+ wb->start_all_reason = reason;
+ wb_wakeup(wb);
}
/**
@@ -1838,14 +1814,6 @@ static struct wb_writeback_work *get_next_work_item(struct bdi_writeback *wb)
list_del_init(&work->list);
}
spin_unlock_bh(&wb->work_lock);
-
- /*
- * Once we start processing a work item that had !nr_pages,
- * clear the wb state bit for that so we can allow more.
- */
- if (work && work->start_all)
- clear_bit(WB_start_all, &wb->state);
-
return work;
}
@@ -1901,6 +1869,30 @@ static long wb_check_old_data_flush(struct bdi_writeback *wb)
return 0;
}
+static long wb_check_start_all(struct bdi_writeback *wb)
+{
+ long nr_pages;
+
+ if (!test_bit(WB_start_all, &wb->state))
+ return 0;
+
+ nr_pages = get_nr_dirty_pages();
+ if (nr_pages) {
+ struct wb_writeback_work work = {
+ .nr_pages = wb_split_bdi_pages(wb, nr_pages),
+ .sync_mode = WB_SYNC_NONE,
+ .range_cyclic = 1,
+ .reason = wb->start_all_reason,
+ };
+
+ nr_pages = wb_writeback(wb, &work);
+ }
+
+ clear_bit(WB_start_all, &wb->state);
+ return nr_pages;
+}
+
+
/*
* Retrieve work items and do the writeback they describe
*/
@@ -1916,6 +1908,11 @@ static long wb_do_writeback(struct bdi_writeback *wb)
finish_writeback_work(wb, work);
}
+ /*
+ * Check for a flush-everything request
+ */
+ wrote += wb_check_start_all(wb);
+
/*
* Check for periodic writeback, kupdated() style
*/
diff --git a/include/linux/backing-dev-defs.h b/include/linux/backing-dev-defs.h
index 420de5c7c7f9..b7c7be6f5986 100644
--- a/include/linux/backing-dev-defs.h
+++ b/include/linux/backing-dev-defs.h
@@ -44,6 +44,28 @@ enum wb_stat_item {
#define WB_STAT_BATCH (8*(1+ilog2(nr_cpu_ids)))
+/*
+ * why some writeback work was initiated
+ */
+enum wb_reason {
+ WB_REASON_BACKGROUND,
+ WB_REASON_VMSCAN,
+ WB_REASON_SYNC,
+ WB_REASON_PERIODIC,
+ WB_REASON_LAPTOP_TIMER,
+ WB_REASON_FREE_MORE_MEM,
+ WB_REASON_FS_FREE_SPACE,
+ /*
+ * There is no bdi forker thread any more and works are done
+ * by emergency worker, however, this is TPs userland visible
+ * and we'll be exposing exactly the same information,
+ * so it has a mismatch name.
+ */
+ WB_REASON_FORKER_THREAD,
+
+ WB_REASON_MAX,
+};
+
/*
* For cgroup writeback, multiple wb's may map to the same blkcg. Those
* wb's can operate mostly independently but should share the congested
@@ -116,6 +138,7 @@ struct bdi_writeback {
struct fprop_local_percpu completions;
int dirty_exceeded;
+ enum wb_reason start_all_reason;
spinlock_t work_lock; /* protects work_list & dwork scheduling */
struct list_head work_list;
diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index 9c0091678af4..dd1d2c23f743 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -41,28 +41,6 @@ enum writeback_sync_modes {
WB_SYNC_ALL, /* Wait on every mapping */
};
-/*
- * why some writeback work was initiated
- */
-enum wb_reason {
- WB_REASON_BACKGROUND,
- WB_REASON_VMSCAN,
- WB_REASON_SYNC,
- WB_REASON_PERIODIC,
- WB_REASON_LAPTOP_TIMER,
- WB_REASON_FREE_MORE_MEM,
- WB_REASON_FS_FREE_SPACE,
- /*
- * There is no bdi forker thread any more and works are done
- * by emergency worker, however, this is TPs userland visible
- * and we'll be exposing exactly the same information,
- * so it has a mismatch name.
- */
- WB_REASON_FORKER_THREAD,
-
- WB_REASON_MAX,
-};
-
/*
* A control structure which tells the writeback code what to do. These are
* always on the stack, and hence need no locking. They are always initialised
diff --git a/include/trace/events/writeback.h b/include/trace/events/writeback.h
index 9b57f014d79d..19a0ea08e098 100644
--- a/include/trace/events/writeback.h
+++ b/include/trace/events/writeback.h
@@ -286,7 +286,6 @@ DEFINE_EVENT(writeback_class, name, \
TP_PROTO(struct bdi_writeback *wb), \
TP_ARGS(wb))
-DEFINE_WRITEBACK_EVENT(writeback_nowork);
DEFINE_WRITEBACK_EVENT(writeback_wake_background);
TRACE_EVENT(writeback_bdi_register,