On Mon, 26 Apr 2010 18:48:42 +0900 Minchan Kim <minchan.kim@xxxxxxxxx> wrote: > On Mon, Apr 26, 2010 at 6:28 PM, KAMEZAWA Hiroyuki > <kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote: > > On Mon, 26 Apr 2010 08:49:01 +0900 > > KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote: > > > >> On Sat, 24 Apr 2010 11:43:24 +0100 > >> Mel Gorman <mel@xxxxxxxxx> wrote: > > > >> > It looks nice but it still broke after 28 hours of running. The > >> > seq-counter is still insufficient to catch all changes that are made to > >> > the list. I'm beginning to wonder if a) this really can be fully safely > >> > locked with the anon_vma changes and b) if it has to be a spinlock to > >> > catch the majority of cases but still a lazy cleanup if there happens to > >> > be a race. It's unsatisfactory and I'm expecting I'll either have some > >> > insight to the new anon_vma changes that allow it to be locked or Rik > >> > knows how to restore the original behaviour which as Andrea pointed out > >> > was safe. > >> > > >> Ouch. > > > > Ok, reproduced. Here is status in my test + printk(). > > > > * A race doesn't seem to happen if swap=off. > > I need to swapon to cause the bug > > FYI, > > Do you have a swapon/off bomb test? No. Just running test under swapoff, and running the same test after swapon. > When I saw your mail, I feel it might be culprit. > > http://lkml.org/lkml/2010/4/22/762. > > It is just guessing. I don't have a time to look into, now. > Hmm. BTW. == static int expand_downwards(struct vm_area_struct *vma, unsigned long address) { .... /* Somebody else might have raced and expanded it already */ if (address < vma->vm_start) { unsigned long size, grow; size = vma->vm_end - address; grow = (vma->vm_start - address) >> PAGE_SHIFT; error = acct_stack_growth(vma, size, grow); if (!error) { vma->vm_start = address; vma->vm_pgoff -= grow; } } == I feel this part needs care. No ? Thanks, -Kmae -- 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>