On Sun, 2009-08-23 at 09:32 +0800, Wu Fengguang wrote: > > > I'd propose to remove the above 'if' and liberate the following three 'if's. > > > > That might work, but it looses the total dirty_thresh constraint. The > > sum of per-bdi dirties _should_ not be larger than that, but I'm not > > sure it won't ever be. > > > > The clip code Richard removed ensured that, and I think I wrote that out > > of more than sheer paranoia, but I'm not sure anymore :/ > > Oh I assumed that your per-bdi throttling is not too permissive to > exceed the global dirty_thresh. In theory the per-bdi throttling > should be able to quickly stop the growing of (nr_reclaimable + > nr_writeback). Once dirty_thresh is reached we already los Right, so: bdi_thresh_n = dirty_thresh * p(n) + eps. and \Sum_n p(n) = 1 So: \Sum_n bdi_thresh_n = dirty_thresh + n*eps Which yields an O(n) error bound. I'm just not sure how large the thing is in reality, and paranoia won out. -- 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