Messages in this thread | | | Date | Sat, 26 Nov 2005 22:21:14 +0300 | From | Oleg Nesterov <> | Subject | Re: [PATCH 1/2] PF_DEAD: cleanup usage |
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Linus Torvalds wrote: > > > So in my opinion PF_DEAD has already slipped into the ->state partly. > > You mis-understand.
Yes.
Ok, I see you point now, thanks.
Oleg.
> PF_DEAD has _always_ been about the task state, in a very serious way. It > didn't "slip into" it. It always was very much about it. > > The problem is that we touch "task->state" in a _lot_ of places: for > example, when we take a page fault, we have to clear it, because we can't > just run with some random task state (see top of __handle_mm_fault). > > PF_DEAD was a "safe haven". It's somewhere that we _don't_ modify the word > in many places, so it doesn't get lost, and we can do sanity checking (ie > we can have things like "BUG_ON(tsk->flags & PF_DEAD)" to make sure that > the task really is valid in a few places. > > Now, arguably the task struct handling is solid enough that maybe we don't > need this any more. But this is what it was all about: it was hidden away > in a non-obvious place exactly _because_ we wanted it hidden away > somewhere where the normal ops wouldn't ever touch it. > > Linus - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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