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[Mehmet Erol Sanliturk]

On Sat, Jun 4, 2016 at 2:38 PM, Matthew Seaman <matthew at freebsd.org> wrote:

> On 2016/06/04 20:27, Bulat Bulat via freebsd-questions wrote:
> > However, the meaning of ts_free member in turnstile structure for me is
> unclear.
> > My understanding: when thread discovers than lock's turnstile is already
> present
> > at turnstile chain it adds its own turnstile to lock's turnstile's
> ts_free
> > and after it wokes up it regrabs turnstile from the same
> > ts_free list of lock's turnstile. But why does it so, if it already has
> its own turnstile, what the
> > meaning of putting of turnstile to free list only for regrabbing it
> later.
>
> This is definitely a question for freebsd-hackers at ...
>
>         Cheers,
>
>         Matthew
>
>
>


This is

put to free list - take it from free list .


A possible another method is to use

dispose - allocate

pair .


When dispose - allocate was taking long time ( in old times ) , the "put to
free - take from free" method was in use .


I am not saying that the reason of the use in your case is that , but there
was such a method in older times .


Mehmet Erol Sanliturk