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Message-ID: <1421225658-3978-1-git-send-email-laijs@cn.fujitsu.com>
Date: Wed, 14 Jan 2015 16:54:14 +0800
From: Lai Jiangshan <laijs@...fujitsu.com>
To: <linux-kernel@...r.kernel.org>
CC: Lai Jiangshan <laijs@...fujitsu.com>, Tejun Heo <tj@...nel.org>,
Yasuaki Ishimatsu <isimatu.yasuaki@...fujitsu.com>,
"Gu, Zheng" <guz.fnst@...fujitsu.com>,
tangchen <tangchen@...fujitsu.com>,
Hiroyuki KAMEZAWA <kamezawa.hiroyu@...fujitsu.com>
Subject: [RFC PATCH 0/2 shit_A shit_B] workqueue: fix wq_numa bug
Hi, All
This patches are un-changloged, un-compiled, un-booted, un-tested,
they are just shits, I even hope them un-sent or blocked.
The patches include two -solutions-:
Shit_A:
workqueue: reset pool->node and unhash the pool when the node is
offline
update wq_numa when cpu_present_mask changed
kernel/workqueue.c | 107 +++++++++++++++++++++++++++++++++++++++++------------
1 file changed, 84 insertions(+), 23 deletions(-)
Shit_B:
workqueue: reset pool->node and unhash the pool when the node is
offline
workqueue: remove wq_numa_possible_cpumask
workqueue: directly update attrs of pools when cpu hot[un]plug
kernel/workqueue.c | 135 +++++++++++++++++++++++++++++++++++++++--------------
1 file changed, 101 insertions(+), 34 deletions(-)
Both patch1 of the both solutions are: reset pool->node and unhash the pool,
it is suggested by TJ, I found it is a good leading-step for fixing the bug.
The other patches are handling wq_numa_possible_cpumask where the solutions
diverge.
Solution_A uses present_mask rather than possible_cpumask. It adds
wq_numa_notify_cpu_present_set/cleared() for notifications of
the changes of cpu_present_mask. But the notifications are un-existed
right now, so I fake one (wq_numa_check_present_cpumask_changes())
to imitate them. I hope the memory people add a real one.
Solution_B uses online_mask rather than possible_cpumask.
this solution remove more coupling between numa_code and workqueue,
it just depends on cpumask_of_node(node).
Patch2_of_Solution_B removes the wq_numa_possible_cpumask and add
overhead when cpu hot[un]plug, Patch3 reduce this overhead.
Thanks,
Lai
Reported-by: Yasuaki Ishimatsu <isimatu.yasuaki@...fujitsu.com>
Cc: Tejun Heo <tj@...nel.org>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@...fujitsu.com>
Cc: "Gu, Zheng" <guz.fnst@...fujitsu.com>
Cc: tangchen <tangchen@...fujitsu.com>
Cc: Hiroyuki KAMEZAWA <kamezawa.hiroyu@...fujitsu.com>
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2.1.0
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