Messages in this thread | | | Subject | Re: [RFC][PATCH 2/2] kernel: extract thread types from task_struct::flags | From | Peter Zijlstra <> | Date | Mon, 20 Sep 2010 21:25:16 +0200 |
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On Mon, 2010-09-20 at 12:14 -0700, Andrew Morton wrote: > On Mon, 20 Sep 2010 17:13:36 +0200 > Peter Zijlstra <a.p.zijlstra@chello.nl> wrote: > > > Free up a few more PF_flags by moving thread types out to their own variable. > > > > Initially I compressed the types into less bits inside task_struct::flags, but > > Thomas suggested I move them to their own field. > > > > There doesn't seem to be a huge point to all this, but I guess there's > some sense in separating "what type of thread this is" from "attributes > of this thread". Maybe. At the expense of a larger task_struct.
Yeah, with the PF_FLUSHER and PF_ALIGNWARN things removed we again have 2 bits free in flags.
And that's the amount -rt consumes (it adds 2 more: I'm a $FOO thread, flags).
But having looked at it, I came up with the compress I'm a $FOO thread, idea. Which would free up a few more bits for future use.
At that time Thomas suggested I move it into a separate field, and then Linus said, don't compact the types, simply transfer the bits we have.
Anyway, it was all very much RFC.. and comments I got :-)
So can you agree with Linus' proposal of simply moving all type like bits over to a new word, or would you rather see the linear type field with an extra helper; possibly part of the existing ->flags field?
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