Hi, Wu. Thanks for Cced me. AFAIR, we discussed this by private mail and didn't conclude yet. Let's start from beginning. On Thu, Jul 22, 2010 at 05:21:55PM +0800, Wu Fengguang wrote: > > I guess this new patch is more problem oriented and acceptable: > > > > --- linux-next.orig/mm/vmscan.c 2010-07-22 16:36:58.000000000 +0800 > > +++ linux-next/mm/vmscan.c 2010-07-22 16:39:57.000000000 +0800 > > @@ -1217,7 +1217,8 @@ static unsigned long shrink_inactive_lis > > count_vm_events(PGDEACTIVATE, nr_active); > > > > nr_freed += shrink_page_list(&page_list, sc, > > - PAGEOUT_IO_SYNC); > > + priority < DEF_PRIORITY / 3 ? > > + PAGEOUT_IO_SYNC : PAGEOUT_IO_ASYNC); > > } > > > > nr_reclaimed += nr_freed; > > This one looks better: > --- > vmscan: raise the bar to PAGEOUT_IO_SYNC stalls > > Fix "system goes totally unresponsive with many dirty/writeback pages" > problem: > > http://lkml.org/lkml/2010/4/4/86 > > The root cause is, wait_on_page_writeback() is called too early in the > direct reclaim path, which blocks many random/unrelated processes when > some slow (USB stick) writeback is on the way. > > A simple dd can easily create a big range of dirty pages in the LRU > list. Therefore priority can easily go below (DEF_PRIORITY - 2) in a > typical desktop, which triggers the lumpy reclaim mode and hence > wait_on_page_writeback(). I see oom message. order is zero. How is lumpy reclaim work? For working lumpy reclaim, we have to meet priority < 10 and sc->order > 0. Please, clarify the problem. > > In Andreas' case, 512MB/1024 = 512KB, this is way too low comparing to > the 22MB writeback and 190MB dirty pages. There can easily be a What's 22MB and 190M? It would be better to explain more detail. I think the description has to be clear as summary of the problem without the above link. Thanks for taking out this problem, again. :) -- Kind regards, Minchan Kim -- 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
