So, overall, On Wed, Mar 20, 2013 at 03:28:00AM +0800, Lai Jiangshan wrote: ... > In this list, we can find that: > 1) wq_mutex protects too much different kind of things.
I don't agree with this and unless you can come up with a much better reason, won't be splitting wq_mutex further. Also, I'm not gonna rename it to wqs_mutex. > 2) workqueue->pwqs are protected by both wq->flush_mutex and pwq_lock, > but in many read sites, they are protected by both wq->flush_mutex and > pwq_lock, > in some other read sites, they are protected by pwq_lock, but can be > converted > to wq->flush_mutex. it means pwq_lock and wq->flush_mutex are redundancy > here. > 3) pwq_lock is global lock, but it protects only workqueue instance fields. A global lock protecting different instances is perfectly fine unless it actually causes contention in some paths. It often actually is better to have a single global lock for cold paths as it pollutes less amount of cache, so please don't split locks for that reason. That said, I like the fact that wq->flush_mutex can be transformed into wq->mutex and replaces pwq_lock making it go away, so, yeah, for that reason, I like pwq_lock removal, so yeah, let's replace pwq_lock with wq->mutex. I applied the ones I can apply at this point. I'll rebase the NUMA patchset on top of the applied ones. Please update the rest on top. Thanks. -- tejun -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
