[lkml]   [2020]   [Sep]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: REGRESSION: 37f4a24c2469: blk-mq: centralise related handling into blk_mq_get_driver_tag
On Thu, Sep 24, 2020 at 10:33:45AM -0400, Theodore Y. Ts'o wrote:
> HOWEVER, thanks to a hint from a colleague at $WORK, and realizing
> that one of the stack traces had virtio balloon in the trace, I
> realized that when I switched the GCE VM type from e1-standard-2 to
> n1-standard-2 (where e1 VM's are cheaper because they use
> virtio-balloon to better manage host OS memory utilization), problem
> has become, much, *much* rarer (and possibly has gone away, although
> I'm going to want to run a lot more tests before I say that
> conclusively) on my test setup. At the very least, using an n1 VM
> (which doesn't have virtio-balloon enabled in the hypervisor) is
> enough to unblock ext4 development.

.... and I spoke too soon. A number of runs using -rc6 are now
failing even with the n1-standard-2 VM, so virtio-ballon may not be an

This is why debugging this is frustrating; it is very much a heisenbug
--- although 5.8 seems to work completely reliably, as does commits
before 37f4a24c2469. Anything after that point will show random
failures. :-(

- Ted

 \ /
  Last update: 2020-09-25 03:15    [W:0.121 / U:1.356 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site