Re: [Bug #14141] order 2 page allocation failures in iwlagn

Frans Pop
2009-10-05T06:51:44Z

On Monday 05 October 2009, Frans Pop wrote:
> I'll dig into this a bit more as it looks like this should be
> reproducible, probably even without the kernel build. Next step is to
> see how .30 behaves in the same situation.

This looks conclusive. I tested .30 and .32-rc3 from clean reboots and
only starting gitk. I only started music playing in the background
(amarok) from an NFS share to ensure network activity.

With .32-rc3 I got 4 SKB allocation errors while starting the *second* gitk
instance. And the system was completely frozen with music stopped until gitk
finished loading.

With .30 I was able to start *three* gitk's (which meant 2 of them got
(partially) swapped out) without any allocation errors. And with the system
remaining relatively responsive. There was a short break in the music while
I started the 2nd instance, but it just continued playing afterwards. There
was also some mild latency in the mouse cursor, but nothing like the full
desktop freeze I get with .32-rc3.

With .30 I looked at /proc/buddyinfo while the 3rd gitk was being started,
and that looked fairly healthy all the time:
Node 0, zone DMA 5 9 22 20 21 11 0 0 0 0 1
Node 0, zone DMA32 579 67 25 8 5 1 1 0 1 1 0
Node 0, zone DMA 5 9 22 20 21 11 0 0 0 0 1
Node 0, zone DMA32 276 54 13 15 8 10 3 1 1 1 0
Node 0, zone DMA 4 9 22 20 21 11 0 0 0 0 1
Node 0, zone DMA32 119 45 24 18 12 4 5 2 1 1 0
Node 0, zone DMA 4 9 22 20 21 11 0 0 0 0 1
Node 0, zone DMA32 527 13 9 5 5 3 2 1 1 1 0
Node 0, zone DMA 5 9 22 20 21 11 0 0 0 0 1
Node 0, zone DMA32 1375 24 7 7 8 5 1 1 0 1 0
Node 0, zone DMA 5 9 22 20 21 11 0 0 0 0 1
Node 0, zone DMA32 329 21 3 3 17 8 5 1 0 1 0

With .32 it was obviously impossible to get that info due to the total
freeze of the desktop. Not sure if the scheduler changes in .32 contribute
to this. Guess I could find out by doing the same test with .31.

One thing I should mention: my swap is an LVM volume that's in a VG that's
on a LUKS encrypted partition.

Does this give you enough info to go on, or should I try a bisection?

Cheers,
FJP