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Date:      Sun, 20 Nov 2011 20:04:21 +0100
From:      Attilio Rao <attilio@freebsd.org>
To:        Kostik Belousov <kostikbel@gmail.com>
Cc:        mdf@freebsd.org, "K. Macy" <kmacy@freebsd.org>, Alan Cox <alc@rice.edu>, Andriy Gapon <avg@freebsd.org>, freebsd-current@freebsd.org, Benjamin Kaduk <kaduk@mit.edu>, Penta Upa <bsdboot@gmail.com>
Subject:   Re: vm_page_t related KBI [Was: Re: panic at vm_page_wire with FreeBSD 9.0 Beta 3]
Message-ID:  <CAJ-FndD-REes_uHY6EZ3xHEtj2Qn3qX0HCb83xELRmVj9=UaJA@mail.gmail.com>
In-Reply-To: <CAJ-FndD%2Bj6WKmsLW9Kv2nDKEJePe=js3xmmj6m6NW3eS1RZD-w@mail.gmail.com>
References:  <20111105141306.GW50300@deviant.kiev.zoral.com.ua> <CAMBSHm86TaJnRRgmPA_t7tiPfQsPyoTqz3ymdHSY1H3t5G864Q@mail.gmail.com> <20111105151530.GX50300@deviant.kiev.zoral.com.ua> <4EB595FA.4020500@rice.edu> <20111106124331.GP50300@deviant.kiev.zoral.com.ua> <4EB81942.70501@rice.edu> <20111107193516.GA50300@deviant.kiev.zoral.com.ua> <CAJ-FndDsrVk7EjjtE=QuhaJE1_k7Q1BvQ%2BxriJPnGzLXJQr1sg@mail.gmail.com> <20111116084542.GY50300@deviant.kiev.zoral.com.ua> <CAJ-FndAwWzFJgpCdaaE=YkipZSCtE6Vb8-LEK2_qS=bVhRM3OQ@mail.gmail.com> <20111118105224.GB50300@deviant.kiev.zoral.com.ua> <CAJ-FndAULb9r-FVaBparSJVtoSEQuX7%2BwhCoBNdQi7n%2B=UpEdA@mail.gmail.com> <CAJ-FndCZqwvbi2N=f=5TxkHH3gaKAGxipPoHBCFLqF=sLOTqdQ@mail.gmail.com> <CAJ-FndD%2Bj6WKmsLW9Kv2nDKEJePe=js3xmmj6m6NW3eS1RZD-w@mail.gmail.com>

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2011/11/20 Attilio Rao <attilio@freebsd.org>:
> 2011/11/18 Attilio Rao <attilio@freebsd.org>:
>> 2011/11/18 Attilio Rao <attilio@freebsd.org>:
>>> 2011/11/18 Kostik Belousov <kostikbel@gmail.com>:
>>>> On Fri, Nov 18, 2011 at 11:40:28AM +0100, Attilio Rao wrote:
>>>>> 2011/11/16 Kostik Belousov <kostikbel@gmail.com>:
>>>>> > On Tue, Nov 15, 2011 at 07:15:01PM +0100, Attilio Rao wrote:
>>>>> >> 2011/11/7 Kostik Belousov <kostikbel@gmail.com>:
>>>>> >> > On Mon, Nov 07, 2011 at 11:45:38AM -0600, Alan Cox wrote:
>>>>> >> >> Ok. =C2=A0I'll offer one final suggestion. =C2=A0Please conside=
r an alternative
>>>>> >> >> suffix to "func". =C2=A0Perhaps, "kbi" or "KBI". =C2=A0In other=
 words, something
>>>>> >> >> that hints at the function's reason for existing.
>>>>> >> >
>>>>> >> > Sure. Below is the extraction of only vm_page_lock() bits, toget=
her
>>>>> >> > with the suggested rename. When Attilio provides the promised si=
mplification
>>>>> >> > of the mutex KPI, this can be reduced.
>>>>> >>
>>>>> >> My tentative patch is here:
>>>>> >> http://www.freebsd.org/~attilio/mutexfileline.patch
>>>>> >>
>>>>> >> I need to make more compile testing later, but it already compiles
>>>>> >> GENERIC + modules fine on HEAD.
>>>>> >>
>>>>> >> The patch provides a common entrypoint, option independent, for bo=
th
>>>>> >> fast case and debug/compat case.
>>>>> >> Additively, it almost entirely fixes the standard violation of the
>>>>> >> reserved namespace, as you described (the notable exception being =
the
>>>>> >> macro used in the fast path, that I want to fix as well, but in a
>>>>> >> separate commit).
>>>>> >>
>>>>> >> Now the file/line couplet can be passed to the "_" suffix variant =
of
>>>>> >> the flag functions.
>>>>> > Yes, this is exactly KPI that I would use when available for the
>>>>> > vm_page_lock() patch.
>>>>> >
>>>>> >>
>>>>> >> eadler@ reviewed the mutex.h comment.
>>>>> >>
>>>>> >> Please let me know what you think about it, as long as we agree on=
 the
>>>>> >> patch I'll commit it.
>>>>> > But I also agree with John that imposing large churn due to the eli=
mination
>>>>> > of the '__' prefix is too late now. At least it will make the chang=
e
>>>>> > non-MFCable. Besides, we already lived with the names for 10+ years=
.
>>>>> >
>>>>> > I will be happy to have the part of the patch that exports the mtx_=
XXX_(mtx,
>>>>> > file, line) defines which can be used without taking care of LOCK_D=
EBUG
>>>>> > or MUTEX_NOINLINE in the consumer code.
>>>>>
>>>>> Ok, this patch should just add the compat stub:
>>>>> http://www.freebsd.org/~attilio/mutexfileline2.patch
>>>> Am I right that I would use mtx_lock_(mtx, file, line) etc ?
>>>> If yes, I am fine with it.
>>>
>>> Yes that is correct.
>>>
>>> However, I'm a bit confused on one aspect: would you mind using
>>> _mtx_lock_flags() instead?
>>> If you don't mind the "underscore namespace violation" I think I can
>>> make a much smaller patch against HEAD for it.
>>>
>>> Otherwise, the one now posted should be ok.
>>
>> After thinking more about it, I think that is basically the shorter
>> version I can came up with.
>>
>> Please consider:
>> http://www.freebsd.org/~attilio/mutexfileline2.patch
>
> This is now committed as r227758,227759, you can update your patch now.

This other patch converts sx to a similar interface which cleans up vm_map.=
c:
http://www.freebsd.org/~attilio/sxfileline.patch

What do you think about it?

Attilio


--=20
Peace can only be achieved by understanding - A. Einstein



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