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 12:14:52 +0900 (JST) |
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> 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.
So I think we have two choices (nick explained it at this thread).
(1) own workqueue (the patch) (2) avoid lru_add_drain_all completely
if you really strongly hate (1), we should target to (2) IMO.
Thought?
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