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Subject: [bug#29409] Remove hugetlb control group on ARM32.
Resent-Message-ID: <handler.29409.B29409.15138715322016@debbugs.gnu.org>
From: ludo@gnu.org (Ludovic =?UTF-8?Q?Court=C3=A8s?=)
References: <877euhtjkj.fsf@gmail.com> <87ind19pok.fsf@gmail.com>
	<20171221095752.1a018320@scratchpost.org>
Date: Thu, 21 Dec 2017 16:52:07 +0100
In-Reply-To: <20171221095752.1a018320@scratchpost.org> (Danny Milosavljevic's
	message of "Thu, 21 Dec 2017 09:57:52 +0100")
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To: Danny Milosavljevic <dannym@scratchpost.org>
Cc: 29409@debbugs.gnu.org

Hi,

Danny Milosavljevic <dannym@scratchpost.org> skribis:

> On Wed, 20 Dec 2017 20:15:07 +0100
> Mathieu Othacehe <m.othacehe@gmail.com> wrote:
>
>> I'm not sure what do about, a workaround could be the ugly hack
>> attached, WDYT ?
>
> I researched cgroups a bit and it seems that /sys/fs/cgroup/hugetlb is fo=
r configuration of hugetlb and that cgroups themselves don't require hugetl=
b - and neither does elogind.

Indeed.  So actually we can probably remove it altogether.

We could simply do that and keep the definition around for when we need
it.

Thoughts?

> We could use (file-exists? "/proc/sys/vm/nr_hugepages") in order to test =
for hugetlb support.  The proc filesystem is already mounted at this point.

Currently we can=E2=80=99t easily introduce special conditions for file sys=
tem
mounts.

> Alternatively, it would be possible to use (needed-for-boot? #f) for the =
hugetlb cgroup file-system.  In that case, maybe failure isn't so bad.  I d=
idn't test that, however.

=E2=80=98need-for-boot?=E2=80=99 tells whether the file system should be mo=
unted from
the initrd or after PID=C2=A01 has been started, so it doesn=E2=80=99t help=
 in this
case (it=E2=80=99s already #f I think.)

Ludo=E2=80=99.