Messages in this thread | | | Date | Wed, 30 Sep 2009 14:10:30 +0200 | From | Jens Axboe <> | Subject | Re: [PATCH 8/8] vm: Add an tuning knob for vm.max_writeback_mb |
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On Wed, Sep 30 2009, Jan Kara wrote: > > +void bdi_writeback_wait(struct backing_dev_info *bdi, long nr_pages) > > +{ > > + struct dirty_throttle_task tt = { > > + .nr_pages = nr_pages, > > + .complete = COMPLETION_INITIALIZER_ONSTACK(tt.complete), > > + }; > > + struct wb_writeback_args args = { > > + .sync_mode = WB_SYNC_NONE, > > + .nr_pages = LONG_MAX, > > + .range_cyclic = 1, > > + .for_background = 1, > > + }; > > + struct bdi_work work; > > + > > + bdi_work_init(&work, &args); > > + work.state |= WS_ONSTACK; > > + > > + /* > > + * make sure we will be waken up by someone > > + */ > > + bdi_queue_work(bdi, &work); > This is wrong, you shouldn't submit the work like this because you'll > have to wait for completion (wb_clear_pending below is just bogus). You > should rather do bdi_start_writeback(bdi, NULL, 0).
Indeed, the above will die a horrible death fairly soon. But we can add some "barrier" like synchronization, if you just wish to wait for previously submitted work to have been completed.
-- Jens Axboe
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