On Sun, 2009-10-11 at 18:50 +0800, Wu Fengguang wrote: > > Sorry for the confusion, but I mean, filesystems have to limit > nr_writeback (directly or indirectly via the block io queue), > otherwise it either hit nr_dirty to 0 (with the loop), or let > nr_writeback grow out of control (without the loop). Doesn't this require the writeback queue to have a limit < dirty_thresh? Or more specifically, for the bdi case: bdi_dirty + bdi_writeback + bdi_unstable <= bdi_thresh we require that the writeback queue be smaller than bdi_thresh, which could be quite difficult, since bdi_thresh can easily be 0. Without observing the bdi_thresh constraint we can have: \Sum_(over bdis) writeback_queue_size dirty pages outstanding, which could be significantly higher than dirty_thresh. Or am I confused again? -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
