Bug 537834

Summary:	sys-kernel/gentoo-sources-3.18.* uses only one NUMA node after suspend/resume
Product:	Gentoo Linux	Reporter:	Martin Kletzander <mkletzan>
Component:	[OLD] Core system	Assignee:	Gentoo Kernel Bug Wranglers and Kernel Maintainers <kernel>
Status:	RESOLVED UPSTREAM
Severity:	normal
Priority:	Normal
Version:	unspecified
Hardware:	x86
OS:	Linux
URL:	https://bugzilla.kernel.org/show_bug.cgi?id=90891
Whiteboard:
Package list:		Runtime testing required:	---

Description Martin Kletzander 2015-01-26 06:30:03 UTC

After resuming from S3, kernel schedules load on only one NUMA node.  I am using 3.18.3, but remember the problem existed roughly since 3.18.

Reproducible: Always

Steps to Reproduce:
1. If you don't have NUMA machine, just compile kernel with CONFIG_NUMA_EMU and boot it with numa=fake=2, for example
2. Suspend to RAM and resume
3. Run some process you know will be multithreaded (e.g. cd /usr/src/linux && make -j)
Actual Results:  
Using top/htop/whatever, you can see that CPUs from one NUMA node (e.g. 0 on my system, not sure about others).

Expected Results:  
All cores/threads are under load.

Comment 1 Mike Pagano gentoo-dev

2015-01-27 18:32:26 UTC

Could you participate in the upstream bug?  It looks like the symptoms described there are similar to yours.

Comment 2 Martin Kletzander 2015-01-29 07:58:22 UTC

(In reply to Mike Pagano from comment #1)
> Could you participate in the upstream bug?  It looks like the symptoms
> described there are similar to yours.

Oh, definitely.  I wasn't sure it applies to vanilla kernel as well.

Comment 3 Mike Pagano gentoo-dev

2015-02-14 00:31:59 UTC

We'll watch the upstream bug and backport any patches we can.