On Wed, Mar 16, 2016 at 01:02:10PM -0400, Chris Metcalf wrote: > Currently you can only request a backtrace of either all cpus, or > all cpus but yourself. It can also be helpful to request a remote > backtrace of a single cpu, and since we want that, the logical > extension is to support a cpumask as the underlying primitive. > > This change modifies the existing lib/nmi_backtrace.c code to take > a cpumask as its basic primitive, and modifies the linux/nmi.h code > to use either the old "all/all_but_self" arch methods, or the new > "cpumask" method, depending on which is available. > > The existing clients of nmi_backtrace (arm and x86) are converted > to using the new cpumask approach in this change.
So the past days I've been staring at RCU stall warns, and they can use a little of this. Their remote stack unwinds are less than useful.
