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    SubjectRe: Overview of concurrency managed workqueue
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    On Wed, 2010-06-16 at 15:39 +0200, Tejun Heo wrote:
    > On 06/16/2010 03:37 PM, Johannes Berg wrote:
    > >> As multiple execution contexts are available for each wq, deadlocks
    > >> around execution contexts is much harder to create. The default
    > >> workqueue, system_wq, has maximum concurrency level of 256 and unless
    > >> there is a use case which can result in a dependency loop involving
    > >> more than 254 workers, it won't deadlock.
    > >
    > > I see a lot of stuff about the current limitations etc., but nothing
    > > about code that actually _relies_ on the synchronisation properties of
    > > the current wqs. We talked about that a long time ago, is it still
    > > guaranteed that a single-threaded wq will serialise all work put onto
    > > it? It needs to be, but I don't see you explicitly mentioning it.
    >
    > Oh yeah, if you have WQ_SINGLE_CPU + max inflight of 1, works on the
    > wq are fully ordered.

    Ok, great, thanks. FWIW, that's pretty much all I care about right
    now :)

    johannes



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