On Mon, Jan 17, 2011 at 04:23:56PM -0500, Chris Mason wrote: > Excerpts from Linus Torvalds's message of 2011-01-17 13:24:55 -0500: > > On Mon, Jan 17, 2011 at 9:40 AM, Chris Mason <chris.mason@xxxxxxxxxx> wrote: > > >> > > > >> > I've reverted 744ed1442757767ffede5008bb13e0805085902e, and > > >> > d8505dee1a87b8d41b9c4ee1325cd72258226fbc and the run has lasted longer > > >> > than any runs in the past. > > >> > > > >> > > >> Confirmed that reverting these patches makes the problem unreproducible > > >> for the many_dd's + fsmark for at least an hour here. > > > > > > After 2+ hours I'm still running with those two commits gone. I'm > > > confident they are the cause of the crashes. I also haven't triggered > > > the cfq stalls without them. > > > > Ok, so the question is how to proceed from here. > > > > I can easily revert them, and since I was planning on doing -rc1 > > tonight, I probably will. But I promised Chris to delay until tomorrow > > if he needed time to chase this down, and while it's now apparently > > chased down, I'll certainly also be open to delaying until tomorrow if > > somebody has a patch to fix it. > > > > So right now my plan is: > > - I will revert those two later today and then release -rc1 in the evening > > UNLESS > > - somebody posts a patch for the problem in the next few hours and > > Chris/others are willing to give it a good test overnight (or whatever > > people feel is "sufficient" based on how easily they can trigger the > > issue), in which case I'd do -rc1 tomorrow (either with the reverts or > > the patch, depending on how testing works out) > > If a patch does come in, I'm happy to test it. Mel had a test that > triggered within 1-2 minutes, mine took 30 or so, which means I'd want a > 2 hour run to convince myself it was really fixed. But, I'll give Mel's > fs_mark + dd workload a try on the buggy kernel. > I spent a while seeing if there was a simple patch but it's not trivially fixable. __activate_page() is getting called in too many different situations to be fully sure the function is doing the right thing in all cases. I also couldn't convince myself that the accounting was correct in all cases. I think the idea of batching updates from mark_page_accessed() in particular is a good idea but the patch needs a do-over. -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab -- 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/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>