Messages in this thread | | | From | KOSAKI Motohiro <> | Subject | Re: [RFC][PATCH] lru_add_drain_all() don't use schedule_on_each_cpu() | Date | Mon, 27 Oct 2008 17:03:51 +0900 (JST) |
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> On Mon, 2008-10-27 at 12:14 +0900, KOSAKI Motohiro wrote: > > > Right, and would be about 4k+sizeof(task_struct), some people might be > > > bothered, but most won't care. > > > > > > > Perhaps, I misunderstand your intension. so can you point your > > > > previous discussion url? > > > > > > my google skillz fail me, but once in a while people complain that we > > > have too many kernel threads. > > > > > > Anyway, if we can re-use this per-cpu workqueue for more goals, I guess > > > there is even less of an objection. > > > > In general, you are right. > > but this is special case. mmap_sem is really widely used various subsystem and drivers. > > (because page fault via copy_user introduce to depend on mmap_sem) > > > > Then, any work-queue reu-sing can cause similar dead-lock easily. > > Yeah, I know, and the cpu-hotplug discussion needed another thread due > to yet another locking incident. I was hoping these two could go > together.
Yeah, I found its thread. (I think it is "work_on_cpu: helper for doing task on a CPU.", right?) So I'll read it soon.
Please wait a bit.
> > Neither are general-purpose workqueues, both need to stay away from the > normal eventd due to deadlocks. > > ego, does you extra thread ever use mmap_sem?
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