On Wed, Mar 16, 2016 at 01:02:10PM -0400, Chris Metcalf wrote:
Currently you can only request a backtrace of either all cpus, orSo the past days I've been staring at RCU stall warns, and they can use
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.
a little of this. Their remote stack unwinds are less than useful.