[PATCH 0/3][SRU/Vivid] cpu hot-remove fails with nvme device

AceLan Kao acelan.kao at canonical.com
Wed Sep 23 07:56:12 UTC 2015


BugLink: http://bugs.launchpad.net/bugs/1498778

[Impact] 
Using cpu hotplug to disable (offline) a cpu:
echo 0 > /sys/devices/system/cpu/cpu10/online
does not return.

Machine is usable, and cpu10 is marked as offline, but any test
scripts hangs because the "echo 0" never returned.

Doing bisect pointed to this commit id:
   a4aea5623d "NVMe: Convert to blk-mq"
Indeed, the test machine in question has an NVMe card.
Doing "rmmod nvme" and then disabling cpus works.

The patch "NVMe: Fix blk-mq hot cpu notification" fixes the issue,
but the system still hangs when re-enable the CPU(echo 1 to online).
We need the other 2 patches to fix the next issue.

[Test Case]
I tested 2 differect machines by the script, both of them passed.
   /usr/share/checkbox/scripts/cpu_offlining

Akinobu Mita (1):
  blk-mq: avoid access hctx->tags->cpumask before allocation

Keith Busch (2):
  NVMe: Fix blk-mq hot cpu notification
  blk-mq: Shared tag enhancements

 block/blk-mq-tag.c        | 38 ++++++++++++++++++++++++++++++++++++++
 block/blk-mq-tag.h        |  2 ++
 block/blk-mq.c            | 19 +++++++++++++++++--
 drivers/block/nvme-core.c | 12 +++++-------
 include/linux/blk-mq.h    |  4 ++++
 5 files changed, 66 insertions(+), 9 deletions(-)

-- 
2.5.0





More information about the kernel-team mailing list