On Mon, 12 Mar 2012, Stanislaw Gruszka wrote: > On Fri, Mar 09, 2012 at 11:58:34AM -0800, Hugh Dickins wrote: > > On Wed, 7 Mar 2012, Hugh Dickins wrote: > > > > > > I'm posting this a little prematurely to get eyes on it, since it's > > > more than a two-liner, but 3.3 time is running out. If it is what's > > > needed to fix my oopses, I won't really be sure before Friday morning. > > > What's running now on the machine affected is using kfree_rcu(), but I > > > did hack it earlier to check that the vfree_rcu() alternative works. > > > > Yes, please do send that patch on to Linus for 3.3. > > > > It did not get as much as the 36 hours of testing I had hoped for, only > > 25 hours so far. 12 hours while I was out yesterday got wasted by a > > wireless driver interrupt spewing approximately one million messages: > > > > iwl3945 0000:08:00.0: MAC is in deep sleep!. CSR_GP_CNTRL = 0xFFFFFFFF > > I replaced that with WARN_ONCE > http://marc.info/?l=linux-wireless&m=132912863701997&w=2 > (the patch is currently in net-next). That's very welcome, thank you. One message will suit me better than a million. But I didn't mention that for every seven of those, there was one slightly different message coming too: iwl3945 0000:08:00.0: UNKNOWN (0xFFFFFFFF) 4294967295 ... (I got bored) > > > which I've not suffered from before, and hope not again. Having kdb > > in, I did take a look what was going on with the memcg load when it was > > interrupted: it appeared to be normal, and I've no reason to suppose that > > my kfree_rcu() was in any way responsible for the wireless aberration. I didn't see it again. I rebooted and ran the test for 63 hours and it went fine this time with no interference from the wifi. I did have the laptop differently positioned this time: maybe it was overheating up against the wall, though that position gave no trouble in the past. > > I don't know if is possible if test patch influence pci or mac80211 code > (we use rcu quite intensively in mac8021). It's very very unlikely that the patch I was testing had a significant effect on RCU usage: the test ends up doing just one extra call_rcu every minute. There's a heavy swapping load running alongside, which shouldn't be disturbing PCI config at all; but it's possible that a temporarily failing memory allocation, or overheat, drove iwl3945 down a strange path on this one occasion, and once there it couldn't recover. Hugh > Those "MAC is in deep sleep" > usually mean that wireless device registers can not be read through pcie > bus - i.e. when pcie bridge is erroneously disabled like in report here: > http://marc.info/?l=linux-wireless&m=132577331132329&w=2 > > Note that wireless device is one of a few connected through pcie bridge > on most of the laptops, others external pcie devices like mmc are not > used frequently, hence breakage in pci code looks frequently like > breakage in wireless driver. Not sure if that was the case here though. > > Stanislaw -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>