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<2c968615-587c-b978-7961-8391c70382b2@nvidia.com> <869059977c224a3aa31bfb42a4a8148d@hisilicon.com> <8eaa47c0-a62d-46da-4fd6-93f2b5b2910d@nvidia.com> <28eb72a6-37de-6e60-9127-d1678aac5f5c@nvidia.com> From: John Hubbard Message-ID: <8d2a373c-d88f-9db2-766d-96bd54e69a40@nvidia.com> Date: Sat, 7 Nov 2020 23:53:07 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.12.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: quoted-printable X-Originating-IP: [172.20.13.39] X-ClientProxiedBy: HQMAIL107.nvidia.com (172.20.187.13) To HQMAIL107.nvidia.com (172.20.187.13) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1604821996; bh=uhtOjw1c2MvJV49ZhsRjq0wZqq8RRq99BhINPnNzlZM=; h=Subject:To:CC:References:From:Message-ID:Date:User-Agent: MIME-Version:In-Reply-To:Content-Type:Content-Language: Content-Transfer-Encoding:X-Originating-IP:X-ClientProxiedBy; b=MXLlR3aY2n7b4ZaOAJyeHosCaXpcIdjKR9hQmCE7qmeqi9GEujnR+U9oncJdfygVn feBZuBZFX6aFi4fxUWuIP5XkrZrGq7q5ZXxb6+BhImS3OCQG18jgO1qxc5e0N7N/EX 3uIXcEN3FmxebllNcZpzcdlRpYH4iRp7UzxDmTjSA7cf4O9N6dvewfalYs2ZaK2OCa mMQs5XSGQyNa/b6oG6h1UCCju1NPW80ICXvKYeaYoCz6rYCpj2JUxduVSUcZ9tJs81 sdMgtxod5EPsZdss15v2tShmxaA3gHlLAe7ks9xLvD4dKbE+WRVCHdp6EgIEQSFN6W t4hLpRvne5zmA== Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/7/20 11:35 PM, Song Bao Hua (Barry Song) wrote: > Or do you want this ? >=20 > (Code B) > diff --git a/mm/Kconfig b/mm/Kconfig > index 01b0ae0cd9d3..a7ff0d31afd5 100644 > --- a/mm/Kconfig > +++ b/mm/Kconfig > @@ -836,6 +836,7 @@ config PERCPU_STATS >=20 > config GUP_TEST > bool "Enable infrastructure for get_user_pages()-related unit te= sts" > + depends on DEBUG_FS > help > Provides /sys/kernel/debug/gup_test, which in turn provides a = way > to make ioctl calls that can launch kernel-based unit tests fo= r > @@ -853,6 +854,9 @@ config GUP_TEST >=20 > See tools/testing/selftests/vm/gup_test.c >=20 > +comment "GUP_TEST needs to have DEBUG_FS enabled" > + depends on !GUP_TEST && !DEBUG_FS > + > config GUP_GET_PTE_LOW_HIGH > bool The above, please. It's your original patch, plus a way to display somethin= g if the "depends on" is not met. >=20 > To be honest, I am not a big fan of both of code A and B. I think "depend= s on" has > clearly said everything the redundant comment wants to say. It's not really just a "comment", in the sense of commenting the Kconfig so= urces. It actually has an effect, which is that it displays something in "make men= uconfig". So it's not redundant, because it provides that output *instead* of hiding = the option entirely, when !DEBUG_FS. Try it out, it's nice. >=20 > =E2=94=82 Symbol: GUP_TEST [=3D] > =E2=94=82 Type : bool > =E2=94=82 Defined at mm/Kconfig:837 > =E2=94=82 Prompt: Enable infrastructure for get_user_pages()-related= unit tests > =E2=94=82 Depends on: DEBUG_FS [=3Dn] > =E2=94=82 Location: > =E2=94=82 (1) -> Memory Management option >=20 > Menuconfig shows GUP_TEST depends on DEBUG_FS and right now DEBUG_FS is > "n". so it is impossible to enable GUP_TEST. >=20 > "comment" is a good thing, but it is more likely to be used for a menu or= a group > of configurations to extend a bundle of things. >=20 > On the other hand, If this particular case needs this comment, so do coun= tless > other configurations in hundreds of Kconfig files. Well, maybe, yes. I personally find it quite difficult, having options appear and disappear o= n me, in this system. If they all had this "comment" behavior by default, to show= up as a placeholder, I think it would be a better user experience. thanks, --=20 John Hubbard NVIDIA