lkml.org 
[lkml]   [2015]   [Oct]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [RFC v2 07/18] kthread: Allow to cancel kthread work
    On Mon 2015-10-05 12:07:58, Petr Mladek wrote:
    > On Fri 2015-10-02 15:24:53, Tejun Heo wrote:
    > > Hello,
    > >
    > > On Fri, Oct 02, 2015 at 05:43:36PM +0200, Petr Mladek wrote:
    > > > IMHO, we need both locks. The worker manipulates more works and
    > > > need its own lock. We need work-specific lock because the work
    > > > might be assigned to different workers and we need to be sure
    > > > that the operations are really serialized, e.g. queuing.
    > >
    > > I don't think we need per-work lock. Do we have such usage in kernel
    > > at all? If you're worried, let the first queueing record the worker
    > > and trigger warning if someone tries to queue it anywhere else. This
    > > doesn't need to be full-on general like workqueue. Let's make
    > > reasonable trade-offs where possible.
    >
    > I actually thought about this simplification as well. But then I am
    > in doubts about the API. It would make sense to assign the worker
    > when the work is being initialized and avoid the duplicate information
    > when the work is being queued:
    >
    > init_kthread_work(work, fn, worker);
    > queue_work(work);
    >
    > Or would you prefer to keep the API similar to workqueues even when
    > it makes less sense here?
    >
    >
    > In each case, we need a way to switch the worker if the old one
    > is destroyed and a new one is started later. We would need
    > something like:
    >
    > reset_work(work, worker)
    > or
    > reinit_work(work, fn, worker)

    I was too fast. We could set "work->worker = NULL" when the work
    finishes and it is not pending. It means that it will be connected
    to the particular worker only when used. Then we could keep the
    workqueues-like API and do not need reset_work().

    I am going to play with this. I feel that it might work.

    Best Regards,
    Petr


    \
     
     \ /
      Last update: 2015-10-05 13:21    [W:4.762 / U:0.312 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site