Messages in this thread | | | Subject | Re: [RFC][PATCH 14/16] writeback: move bdi threads exiting logic to the forker thread | From | Artem Bityutskiy <> | Date | Tue, 20 Jul 2010 15:54:26 +0300 |
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On Sun, 2010-07-18 at 03:02 -0400, Christoph Hellwig wrote: > Yes, only killing threads from the caller is much better, that's how > the kthread API is supposed to be used anyway. > > > static void bdi_queue_work(struct backing_dev_info *bdi, > > struct wb_writeback_work *work) > > { > > + bool wakeup_default = false; > > + > > trace_writeback_queue(bdi, work); > > > > spin_lock(&bdi->wb_lock); > > list_add_tail(&work->list, &bdi->work_list); > > - spin_unlock(&bdi->wb_lock); > > - > > /* > > * If the default thread isn't there, make sure we add it. When > > * it gets created and wakes up, we'll run this work. > > */ > > - if (unlikely(!bdi->wb.task)) { > > + if (unlikely(!bdi->wb.task)) > > + wakeup_default = true; > > + else > > + wake_up_process(bdi->wb.task); > > + spin_unlock(&bdi->wb_lock); > > + > > + if (wakeup_default) { > > trace_writeback_nothread(bdi, work); > > wake_up_process(default_backing_dev_info.wb.task); > > Why not simply do the defaul thread wakeup under wb_lock, too? > It keeps the code a lot simpler, and this is not a typical path anyway.
Hmm, actually, I want to take this lock in __mark_inode_dirty() as well, so it makes sense to micro-optimize this. Also, can 'trace_writeback_nothread()' be called under a spinlock? If no, then a variable is needed anyway.
-- Best Regards, Artem Bityutskiy (Артём Битюцкий)
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