diff options
| -rw-r--r-- | fs/fs-writeback.c | 17 |
1 files changed, 5 insertions, 12 deletions
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 025a63894cf0..fddd8abd839a 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -255,6 +255,7 @@ static void wb_wait_for_completion(struct backing_dev_info *bdi, /* if foreign slots >= 8, switch */ #define WB_FRN_HIST_MAX_SLOTS (WB_FRN_HIST_THR_SLOTS / 2 + 1) /* one round can affect upto 5 slots */ +#define WB_FRN_MAX_IN_FLIGHT 1024 /* don't queue too many concurrently */ static atomic_t isw_nr_in_flight = ATOMIC_INIT(0); static struct workqueue_struct *isw_wq; @@ -507,18 +508,13 @@ static void inode_switch_wbs(struct inode *inode, int new_wb_id) if (inode->i_state & I_WB_SWITCH) return; - /* - * Avoid starting new switches while sync_inodes_sb() is in - * progress. Otherwise, if the down_write protected issue path - * blocks heavily, we might end up starting a large number of - * switches which will block on the rwsem. - */ - if (!down_read_trylock(&bdi->wb_switch_rwsem)) + /* avoid queueing a new switch if too many are already in flight */ + if (atomic_read(&isw_nr_in_flight) > WB_FRN_MAX_IN_FLIGHT) return; isw = kzalloc(sizeof(*isw), GFP_ATOMIC); if (!isw) - goto out_unlock; + return; /* find and pin the new wb */ rcu_read_lock(); @@ -552,15 +548,12 @@ static void inode_switch_wbs(struct inode *inode, int new_wb_id) call_rcu(&isw->rcu_head, inode_switch_wbs_rcu_fn); atomic_inc(&isw_nr_in_flight); - - goto out_unlock; + return; out_free: if (isw->new_wb) wb_put(isw->new_wb); kfree(isw); -out_unlock: - up_read(&bdi->wb_switch_rwsem); } /** |