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Re: [PATCH] Relay CPU Hotplug support
- From: Andrew Morton <akpm at osdl dot org>
- To: ego at in dot ibm dot com, Oleg Nesterov <oleg at tv-sign dot ru>
- Cc: Mathieu Desnoyers <mathieu dot desnoyers at polymtl dot ca>, linux-kernel at vger dot kernel dot org, David Wilder <dwilder at us dot ibm dot com>, Tom Zanussi <zanussi at us dot ibm dot com>, Ingo Molnar <mingo at redhat dot com>, Greg Kroah-Hartman <gregkh at suse dot de>, Christoph Hellwig <hch at infradead dot org>, ltt-dev at shafik dot org, systemtap at sources dot redhat dot com, Douglas Niehaus <niehaus at eecs dot ku dot edu>, "Martin J. Bligh" <mbligh at mbligh dot org>, Thomas Gleixner <tglx at linutronix dot de>, kiran at scalex86 dot org, venkatesh dot pallipadi at intel dot com, dipankar at in dot ibm dot com, vatsa at in dot ibm dot com, torvalds at osdl dot org, davej at redhat dot com
- Date: Fri, 22 Dec 2006 02:44:58 -0800
- Subject: Re: [PATCH] Relay CPU Hotplug support
- References: <20061221003101.GA28643@Krystal> <20061220232350.eb4b6a46.akpm@osdl.org> <20061222103724.GA29348@in.ibm.com>
On Fri, 22 Dec 2006 16:07:24 +0530
Gautham R Shenoy <ego@in.ibm.com> wrote:
> While we are at this per-subsystem cpuhotplug "locking", here's a
> proposal that might put an end to the workqueue deadlock woes.
Oleg is working on some patches which will permit us to cancel or wait upon
a particular work_struct, rather than upon all pending work_structs.
This will fix the problem where we accidentlly wait upon some unrelated
work_struct which takes a lock which is related to one which we already
hold.
I hope. It'll be a bit tricky to implement: if some foreign work_struct is
running right now, we cannot wait upon it - we must non-blockingly dequeue
the work_struct which we want to kill before it gets to run.