Re: [PATCH v4 3/4] futex: Document ordering guarantees

From: Randy Dunlap
Date: Thu Dec 19 2013 - 18:05:27 EST


On 12/19/13 13:07, Darren Hart wrote:
> On Thu, 2013-12-19 at 13:00 -0800, Davidlohr Bueso wrote:
>> On Thu, 2013-12-19 at 12:51 -0800, Randy Dunlap wrote:
>>> On 12/19/13 12:45, Davidlohr Bueso wrote:
>>>> From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
>>>>
>>>> That's essential, if you want to hack on futexes.
>>>>
>>>> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
>>>> Cc: Darren Hart <dvhart@xxxxxxxxxxxxxxx>
>>>> Acked-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
>>>> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
>>>> Cc: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
>>>> Cc: Mike Galbraith <efault@xxxxxx>
>>>> Cc: Jeff Mahoney <jeffm@xxxxxxxx>
>>>> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
>>>> Cc: Scott Norton <scott.norton@xxxxxx>
>>>> Cc: Tom Vaden <tom.vaden@xxxxxx>
>>>> Cc: Aswin Chandramouleeswaran <aswin@xxxxxx>
>>>> Cc: Waiman Long <Waiman.Long@xxxxxx>
>>>> Cc: Jason Low <jason.low2@xxxxxx>
>>>> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
>>>> Signed-off-by: Davidlohr Bueso <davidlohr@xxxxxx>
>>>> ---
>>>> kernel/futex.c | 57 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>>>> 1 file changed, 57 insertions(+)
>>>>
>>>> diff --git a/kernel/futex.c b/kernel/futex.c
>>>> index 577481d..af1fc31 100644
>>>> --- a/kernel/futex.c
>>>> +++ b/kernel/futex.c
>>>> @@ -69,6 +69,63 @@
>>>>
>>>> #include "locking/rtmutex_common.h"
>>>>
>>>> +/*
>>>> + * Basic futex operation and ordering guarantees:
>>>> + *
>>>> + * The waiter reads the futex value in user space and calls
>>>> + * futex_wait(). It computes the hash bucket and acquires the hash
>>>
>>> does It
>>> refer to "the waiter" or to futex_wait()?
>>> I read it as referring to the waiter, but ISTM that the comments are using It
>>> to refer to futex_wait()... ???
>>>
>>
>> Yes, it refers to futex_wait(), which IMO in a futex context is pretty
>> clear.
>
>
> Agreed.
>
>

I'll just have to get by with disagreeing with both of you then.
I say that the pronoun's antecedent is ambiguous (unclear).

--
~Randy
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/