> > No, we _start_ writeback for 1.5*ratelimit_pages pages, but do not > > wait for those writebacks to finish. > > > > So for a slow device and a fast writer, dirty+writeback can indeed > > increase beyond the dirty threshold. > > > > Nope, try it. > > If a process dirties 1000 pages it'll then go into balance_dirty_pages() > and start writeback against 1,500 pages. When we hit dirty_ratio that > process will be required to write back 1,500 pages for each eight pages > which it dirtied. We'll quickly reach the stage where there are no longer > 1,500 pages to be written back and the process will block in > balance_dirty_pages() until the dirty+writeback level subsides.
OK. I was confused by this: static long ratelimit_pages = 32; and didn't realize, that that 32 is totally irrelevant. So I'm still right, that for N dirty pages, the writer is allowed to dirty N/1500*8 more dirty pages, but I agree, that this isn't really an issue. 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/
