On Thu, Nov 22, 2012 at 10:10 AM, Rafael Aquini <aquini@xxxxxxxxxx> wrote: > On Thu, Nov 22, 2012 at 09:19:15AM -0500, Sasha Levin wrote: >> And managed to reproduce it only once through last night, here is the dump I got >> before the oops: >> >> [ 2760.356820] page:ffffea0000d00e00 count:1 mapcount:-2147287036 mapping:00000000000004f4 index:0xd00e00000003 >> [ 2760.362354] page flags: 0x350000000001800(private|private_2) >> > > Thanks alot for following up this one Sasha. > > > We're stumbling across a private page -- seems something in your setup is doing > this particular usage, and that's probably why I'm not seeing the same here. > > Regardless being a particular case or not, we shouldn't be poking at that > private page, so I figured the tests I'm doing at balloon_page_movable() are > incomplete and dumb. > > Perhaps, a better way to proceed here would be assuring the NR_PAGEFLAGS > rightmost bits from page->flags are all cleared, as this is the state a page > coming from buddy to the balloon list will be, and this is the state the balloon > page flags will be kept as long as it lives as such (we don't play with any flag > at balloon level). > > > Here goes what I'll propose after you confirm it doesn't trigger your crash > anymore, as it simplifies the code and reduces the testing battery @ > balloon_page_movable() -- ballooned pages have no flags set, 1 refcount and 0 > mapcount, always. > > > Could you give this a try? > > Thank you! Ran it for a while, no more BUGs, yay :) Thanks, Sasha -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>