Re: [PATCH v7 1/4] spinlock: A new lockref structure for locklessupdate of refcount

[Waiman Long]

On 09/03/2013 03:09 PM, Linus Torvalds wrote:
> On Tue, Sep 3, 2013 at 8:34 AM, Linus Torvalds
> <torvalds@xxxxxxxxxxxxxxxxxxxx>  wrote:
> > I suspect the tty_ldisc_lock() could be made to go away if we care.
> Heh. I just pulled the tty patches from Greg, and the locking has
> changed completely.
>
> It may actually fix your AIM7 test-case, because while the global
> spinlock remains (it got renamed to "tty_ldiscs_lock" - there's an
> added "s"), the common operations now take the per-tty lock to get the
> ldisc for that tty, rather than that global spinlock (which just
> protects the actual ldisk array now).
>
> That said, I don't know what AIM7 really ends up doing, but your
> profile seems to have every access through tty_ldisc_[de]ref() that
> now uses only the per-tty lock. Of course, how much that helps ends up
> depending on whether AIM7 uses lots of tty's or just one shared one.
>
> Anyway, it might be worth testing my current -git tree.
>
>                    Linus

Thank for the news. I will fetch your latest git tree and try it out.

-Longman
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