Re: [PATCH V2 Resend 3/4] workqueue: Schedule work on non-idle cpuinstead of current one
From: Viresh Kumar
Date: Fri Jan 04 2013 - 06:11:43 EST
On 27 November 2012 10:49, Viresh Kumar <viresh.kumar@xxxxxxxxxx> wrote:
> On 26 November 2012 22:45, Tejun Heo <tj@xxxxxxxxxx> wrote:
>> On Tue, Nov 06, 2012 at 04:08:45PM +0530, Viresh Kumar wrote:
>> I'm pretty skeptical about this. queue_work() w/o explicit CPU
>> assignment has always guaranteed that the work item will be executed
>> on the same CPU. I don't think there are too many users depending on
>> that but am not sure at all that there are none. I asked you last
>> time that you would at the very least need to audit most users but it
>> doesn't seem like there has been any effort there.
> My bad. I completely missed/forgot that comment from your earlier mails.
> Will do it.
And this is the first thing i did this year :)
So there are almost 1200 files which are using: queue_work, queue_delayed_work,
schedule_work, schedule_delayed_work or schedule_on_each_cpu
Obviously i can't try to understand all of them :) , and so i tried to
strings in them: "cpu" or "processor_id". So, this would catch every
file of these 1200
odd files which use some variables/comment/code with cpu or smp_processor_id or
I got around 650 files with these two searches.. Then i went into
these files to see if
there is anything noticeable, which may break due to this patch...
I got a list of files where cpu/processor_id strings are found, which
may break with
this patch (still can't guarantee as i don't have knowledge of these drivers)...
- drivers/infiniband/hw/qib/qib_iba7322.c and
- fs/file.c, file_table.c, fs/fscache/object.c
- include/linux/stop_machine.h, kernel/stop_machine.c
I am not sure what to do now :) , can you assist ?
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