> > > so it could be that: scale / cycle > 1 > > > by a very small amount; however: > > > > No, I'm worried about the case when scale is too small. If the > > per-bdi threshold becomes smaller than stat_threshold, then things > > won't work, because dirty+writeback will never go below the threshold, > > possibly resulting in the deadlock we are trying to avoid. > > /me goes refresh the deadlock details.. > > A writes to B; A exceeds the dirty limit but writeout is blocked by B > because the dirty limit is exceeded, right? > > This cannot happen when we decouple the BDI dirty thresholds, even when > a threshold is 0. > > A write to B; A exceeds A's limit and writes to B, B has limit of 0, the > 1 dirty page gets written out (we gain ratio) and life goes on. > > Right?
If the limit is zero, then we need the per-bdi dirty+write to go to zero, otherwise balance_dirty_pages() loops. But the per-bdi writeback counter is not necessarily updated after the writeback, because the per-bdi per-CPU counter may not trip the update of the per-bdi counter. Miklos - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
