On Mon, Nov 29, 2010 at 03:08:24PM +0000, Mel Gorman wrote: > Ouch! I have been unable to create an exact copy of your kernel source as > I'm not running Fedora. From a partial conversion of a source RPM, I saw no > changes related to mm/vmscan.c. Is this accurate? I'm trying to establish > if this is a mainline bug as well. > Sorry, if you extract the source rpm you should get the patched sources... Aside from a few patches to mm/mmap for execshield, mm/* is otherwise untouched from the latest stable 2.6.35 kernels. If you git clone git://pkgs.fedoraproject.org/kernel and check out the origin/f14/master branch, it has all the patches we apply (based on the 'ApplyPatch' lines in kernel.spec > Second, I see all the stack traces are marked with "?" making them > unreliable. Is that anything to be concerned about? > Hrm, I don't think it is, I think the ones with '?' are just artifacts because we don't have a proper unwinder. Oh! Thanks! I just found a bug in our configs... We don't have CONFIG_FRAME_POINTER set because CONFIG_DEBUG_KERNEL got unset in the 'production' configs... I'll fix that up. > I see that one user has reported that the patches fixed the problem for him > but I fear that this might be a co-incidence or that the patches close a > race of some description. Specifically, I'm trying to identify if there is > a situation where kswapd() constantly loops checking watermarks and never > calling cond_resched(). This could conceivably happen if kswapd() is always > checking sleeping_prematurely() at a higher order where as balance_pgdat() > is always checks the watermarks at the lower order. I'm not seeing how this > could happen in 2.6.35.6 though. If Fedora doesn't have special changes, > it might mean that these patches do need to go into -stable as the > cost of zone_page_state_snapshot() is far higher on larger machines than > previously reported. > Yeah, I am a bit surprised as well. Luke seems to have quite a large machine... I haven't seen any kswapd lockups there on my 18G machine using the same kernel. :< (Possibly it's just not stressed enough though.) Thanks for looking into this! Kyle -- 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>