On Mon, Apr 26, 2010 at 6:49 PM, KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote: > 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 ? Yes. Andrea pointed it out. I didn't followed the thread whole yet but It seems Mel and Andrea want to restore anon_vma's atomicity like old than one by one healing. -- Kind regards, Minchan Kim -- 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