On Mon, 15 Mar 2010 13:34:50 +0100 Christian Ehrhardt <ehrhardt@xxxxxxxxxxxxxxxxxx> wrote: > c) If direct reclaim did reasonable progress in try_to_free but did not > get a page, AND there is no write in flight at all then let it try again > to free up something. > This could be extended by some kind of max retry to avoid some weird > looping cases as well. > > d) Another way might be as easy as letting congestion_wait return > immediately if there are no outstanding writes - this would keep the > behavior for cases with write and avoid the "running always in full > timeout" issue without writes. They're pretty much equivalent and would work. But there are two things I still don't understand: 1: Why is direct reclaim calling congestion_wait() at all? If no writes are going on there's lots of clean pagecache around so reclaim should trivially succeed. What's preventing it from doing so? 2: This is, I think, new behaviour. A regression. What caused it? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>