Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

From	Florian Weimer <fweimer@redhat.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy
Date	2015-10-25 14:20 +0100
Message-ID	<qntnj-3sA-1@gated-at.bofh.it> (permalink)
References	(6 earlier) <qnkDo-481-3@gated-at.bofh.it> <qnpWp-FB-5@gated-at.bofh.it> <qnr29-1Dl-7@gated-at.bofh.it> <qnr2a-1Dl-23@gated-at.bofh.it> <qns7U-2xF-3@gated-at.bofh.it>
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On 10/25/2015 12:58 PM, Theodore Ts'o wrote:

> Well, I was thinking we could just teach them to use
> "syscall(SYS_gettid)".

Right, and that's easier if TIDs are officially part of the GNU API.

I think the worry is that some future system might have TIDs which do
not share the PID space, or are real descriptors (that they need
explicit open and close operations).

> On a different subject, I'm going to start telling people to use
> "syscall(SYS_getrandom)", since I think that's going to be easier than
> having asking people to change their Makefiles to link against some
> Linux-specific library, but that's a different debate, and I recognize
> the glibc folks aren't willing to bend on that one.

I think we can reach consensus for an implementation which makes this code

  unsigned char session_key[32];
  getrandom (session_key, sizeof (session_key), 0);
  install_session_key (session_key);

correct.  That is, no error handling code for ENOMEM, ENOSYS, EINTR,
ENOMEM or short reads is necessary.  It seems that several getrandom
wrappers currently built into applications do not get this completely right.

Florian

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Thread

Re: [PATCH 3/3] sched: Implement interface for cgroup unified  hierarchy Tejun Heo <tj@kernel.org> - 2015-10-24 00:30 +0200
  Re: [PATCH 3/3] sched: Implement interface for cgroup unified  hierarchy Mike Galbraith <umgwanakikbuti@gmail.com> - 2015-10-24 06:40 +0200
    Re: [PATCH 3/3] sched: Implement interface for cgroup unified  hierarchy Tejun Heo <tj@kernel.org> - 2015-10-25 03:20 +0100
      Re: [PATCH 3/3] sched: Implement interface for cgroup unified  hierarchy Mike Galbraith <umgwanakikbuti@gmail.com> - 2015-10-25 04:50 +0100
        Re: [PATCH 3/3] sched: Implement interface for cgroup unified  hierarchy Tejun Heo <tj@kernel.org> - 2015-10-27 04:20 +0100
          Re: [PATCH 3/3] sched: Implement interface for cgroup unified  hierarchy Mike Galbraith <umgwanakikbuti@gmail.com> - 2015-10-27 06:50 +0100
            Re: [PATCH 3/3] sched: Implement interface for cgroup unified  hierarchy Tejun Heo <tj@kernel.org> - 2015-10-27 06:50 +0100
              Re: [PATCH 3/3] sched: Implement interface for cgroup unified  hierarchy Mike Galbraith <umgwanakikbuti@gmail.com> - 2015-10-27 07:00 +0100
                Re: [PATCH 3/3] sched: Implement interface for cgroup unified  hierarchy Tejun Heo <tj@kernel.org> - 2015-10-27 07:10 +0100
                Re: [PATCH 3/3] sched: Implement interface for cgroup unified  hierarchy Mike Galbraith <umgwanakikbuti@gmail.com> - 2015-10-27 07:10 +0100
      Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy Linus Torvalds <torvalds@linux-foundation.org> - 2015-10-25 05:00 +0100
        Re: [PATCH 3/3] sched: Implement interface for cgroup unified  hierarchy Ingo Molnar <mingo@kernel.org> - 2015-10-25 10:40 +0100
          Re: [PATCH 3/3] sched: Implement interface for cgroup unified  hierarchy Theodore Ts'o <tytso@mit.edu> - 2015-10-25 11:50 +0100
            Re: [PATCH 3/3] sched: Implement interface for cgroup unified  hierarchy Florian Weimer <fweimer@redhat.com> - 2015-10-25 11:50 +0100
              Re: [PATCH 3/3] sched: Implement interface for cgroup unified  hierarchy Theodore Ts'o <tytso@mit.edu> - 2015-10-25 13:00 +0100
                Re: [PATCH 3/3] sched: Implement interface for cgroup unified  hierarchy Florian Weimer <fweimer@redhat.com> - 2015-10-25 14:20 +0100
                Getrandom wrapper Theodore Ts'o <tytso@mit.edu> - 2015-10-25 14:50 +0100
                Re: Getrandom wrapper Florian Weimer <fweimer@redhat.com> - 2015-10-26 14:40 +0100
                Re: [PATCH 3/3] sched: Implement interface for cgroup unified  hierarchy Peter Zijlstra <peterz@infradead.org> - 2015-10-26 15:20 +0100

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