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From: Tejun Heo <tj@kernel.org>
To: Aleksa Sarai <cyphar@cyphar.com>
Cc: lizefan@huawei.com, mingo@redhat.com, peterz@infradead.org,
	richard@nod.at, "Frédéric Weisbecker" <fweisbec@gmail.com>,
	linux-kernel@vger.kernel.org, cgroups@vger.kernel.org
Subject: Re: [PATCH v8 3/4] cgroups: allow a cgroup subsystem to reject a fork
Date: Mon, 6 Apr 2015 11:05:36 -0400	[thread overview]
Message-ID: <20150406150536.GA10582@htj.duckdns.org> (raw)
In-Reply-To: <CAOviyai9dvCTGK=VUm0uDSo7XbmKk1BFDrRzL15ppAWf8YjG3w@mail.gmail.com>

Hello, Aleksa.

On Fri, Apr 03, 2015 at 10:42:27AM +1100, Aleksa Sarai wrote:
> I tried doing this and the kernel would refuse to boot. I believe it has
> something to do with the ordering of early_init subsystems, but I'm not

Hmmm... yeah, failure in early_init can be tricky to debug.

> entirely sure (this optimisation can be dealt with later [it's non-critical],
> so IMO this should be done in a separate patchset [if at all]). Also, your
> later comments would fix the subsys bitmask problem (we can just pass the
> default %NULL), we don't even need to test the index.

But we'd be adding quite a few loops in relatively hot paths.  I don't
think it's a good idea to send the patches as-are because we can't
debug and fix them properly, right?  If there are hard ordering
dependencies, the range of subsystems which require fork/exit doesn't
have to be at the beginning.

Thanks.

-- 
tejun

  reply	other threads:[~2015-04-06 15:05 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-04-01  8:57 [PATCH v8 0/4] cgroups: add pids subsystem Aleksa Sarai
2015-04-01  8:57 ` [PATCH v8 1/4] cgroups: use bitmask to filter for_each_subsys Aleksa Sarai
2015-04-01  8:57 ` [PATCH v8 2/4] cgroups: replace explicit ss_mask checking with for_each_subsys_which Aleksa Sarai
2015-04-01  8:57 ` [PATCH v8 3/4] cgroups: allow a cgroup subsystem to reject a fork Aleksa Sarai
2015-04-01 16:02   ` Tejun Heo
2015-04-02 23:42     ` Aleksa Sarai
2015-04-06 15:05       ` Tejun Heo [this message]
2015-04-07 13:47         ` Aleksa Sarai
2015-04-07 14:00           ` Tejun Heo
2015-04-01  8:57 ` [PATCH v8 4/4] cgroups: implement the PIDs subsystem Aleksa Sarai

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