Commit 0e63a5c6 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'docs-5.12' of git://git.lwn.net/linux 

Pull documentation updates from Jonathan Corbet:
 "It has been a relatively quiet cycle in docsland.

   - As promised, the minimum Sphinx version to build the docs is now
     1.7, and we have dropped support for Python 2 entirely. That
     allowed the removal of a bunch of compatibility code.

   - A set of treewide warning fixups from Mauro that I applied after it
     became clear nobody else was going to deal with them.

   - The automarkup mechanism can now create cross-references from
     relative paths to RST files.

   - More translations, typo fixes, and warning fixes"

* tag 'docs-5.12' of git://git.lwn.net/linux: (75 commits)
  docs: kernel-hacking: be more civil
  docs: Remove the Microsoft rhetoric
  Documentation/admin-guide: kernel-parameters: Update nohlt section
  doc/admin-guide: fix spelling mistake: "perfomance" -> "performance"
  docs: Document cross-referencing using relative path
  docs: Enable usage of relative paths to docs on automarkup
  docs: thermal: fix spelling mistakes
  Documentation: admin-guide: Update kvm/xen config option
  docs: Make syscalls' helpers naming consistent
  coding-style.rst: Avoid comma statements
  Documentation: /proc/loadavg: add 3 more field descriptions
  Documentation/submitting-patches: Add blurb about backtraces in commit messages
  Docs: drop Python 2 support
  Move our minimum Sphinx version to 1.7
  Documentation: input: define ABS_PRESSURE/ABS_MT_PRESSURE resolution as grams
  scripts/kernel-doc: add internal hyperlink to DOC: sections
  Update Documentation/admin-guide/sysctl/fs.rst
  docs: Update DTB format references
  docs: zh_CN: add iio index.rst translation
  docs/zh_CN: add iio ep93xx_adc.rst translation
  ...
parents ae42c317 3c2e0a48

Documentation/RCU/RTFP.txt

+47 −47
Original line number Diff line number Diff line
@@ -683,7 +683,7 @@ Orran Krieger and Rusty Russell and Dipankar Sarma and Maneesh Soni" 
,month="October"

,year="2001"

,note="Available:

\url{http://lkml.org/lkml/2001/10/13/105}

\url{https://lore.kernel.org/r/Pine.LNX.4.33.0110131015410.8707-100000@penguin.transmeta.com}

[Viewed August 21, 2004]"

,annotation={

}
@@ -826,7 +826,7 @@ Symposium on Distributed Computing} 
,month="October"

,year="2002"

,note="Available:

\url{https://lkml.org/lkml/2002/10/24/262}

\url{https://lore.kernel.org/r/3DB86B05.447E7410@us.ibm.com}

[Viewed February 15, 2014]"

,annotation={

	Mingming Cao's patch to introduce RCU to SysV IPC.
@@ -839,7 +839,7 @@ Symposium on Distributed Computing} 
,month="March"

,year="2003"

,note="Available:

\url{http://lkml.org/lkml/2003/3/9/205}

\url{https://lore.kernel.org/r/Pine.LNX.4.44.0303091831560.2129-100000@home.transmeta.com}

[Viewed March 13, 2006]"

,annotation={

	Linus suggests replacing brlock with RCU and/or seqlocks:
@@ -1036,15 +1036,15 @@ Add per-cpu batch counter" 
,annotation={

	RCU runs reasonably on a 512-CPU SGI using Manfred Spraul's patches,

	which may be found at:

	https://lkml.org/lkml/2004/5/20/49 (split vars into cachelines)

	https://lkml.org/lkml/2004/5/22/114 (cpu_quiet() patch)

	https://lkml.org/lkml/2004/5/25/24 (0/5)

	https://lkml.org/lkml/2004/5/25/23 (1/5)

		https://lkml.org/lkml/2004/5/25/265 (works for Jack)

	https://lkml.org/lkml/2004/5/25/20 (2/5)

	https://lkml.org/lkml/2004/5/25/22 (3/5)

	https://lkml.org/lkml/2004/5/25/19 (4/5)

	https://lkml.org/lkml/2004/5/25/21 (5/5)

	https://lore.kernel.org/r/40AC9823.6020709@colorfullife.com (split vars into cachelines)

	https://lore.kernel.org/r/Pine.LNX.4.44.0405222141260.11106-100000@dbl.q-ag.de (cpu_quiet() patch)

	https://lore.kernel.org/r/200405250535.i4P5ZJo8017583@dbl.q-ag.de (0/5)

	https://lore.kernel.org/r/200405250535.i4P5ZKAQ017591@dbl.q-ag.de (1/5)

		https://lore.kernel.org/r/20040525203215.GB5127@sgi.com (works for Jack)

	https://lore.kernel.org/r/200405250535.i4P5ZLiR017599@dbl.q-ag.de (2/5)

	https://lore.kernel.org/r/200405250535.i4P5ZMFt017607@dbl.q-ag.de (3/5)

	https://lore.kernel.org/r/200405250535.i4P5ZN6g017615@dbl.q-ag.de (4/5)

	https://lore.kernel.org/r/200405250535.i4P5ZO7I017623@dbl.q-ag.de (5/5)

}

}
@@ -1106,7 +1106,7 @@ Oregon Health and Sciences University" 
,month="August"

,year="2004"

,note="Available:

\url{http://lkml.org/lkml/2004/8/6/237}

\url{https://lore.kernel.org/r/20040807192424.GF3936@in.ibm.com}

[Viewed June 8, 2010]"

,annotation={

	Introduce rcu_dereference().
@@ -1119,7 +1119,7 @@ Oregon Health and Sciences University" 
,month="August"

,year="2004"

,note="Available:

\url{http://lkml.org/lkml/2004/8/30/87}

\url{https://lore.kernel.org/r/1093873222.984.12.camel@new.localdomain}

[Viewed February 17, 2005]"

,annotation={

	Uses active code in rcu_read_lock() and rcu_read_unlock() to
@@ -1186,7 +1186,7 @@ Oregon Health and Sciences University" 
,month="October"

,year="2004"

,note="Available:

\url{http://lkml.org/lkml/2004/10/23/241}

\url{https://lore.kernel.org/r/20041023202723.GA1930@us.ibm.com}

[Viewed June 8, 2010]"

,annotation={

	Introduce rcu_assign_pointer().
@@ -1203,7 +1203,7 @@ Oregon Health and Sciences University" 
,annotation={

	James Morris posts Kaigai Kohei's patch to LKML.

	[Viewed December 10, 2004]

	Kaigai's patch is at https://lkml.org/lkml/2004/9/27/52

	Kaigai's patch is at https://lore.kernel.org/r/200409271057.i8RAvcA1007873@mailsv.bs1.fc.nec.co.jp

}

}
@@ -1241,7 +1241,7 @@ Oregon Health and Sciences University" 
,year="2005"

,day="17"

,note="Available:

\url{http://lkml.org/lkml/2005/3/17/199}

\url{https://lore.kernel.org/r/20050318002026.GA2693@us.ibm.com}

[Viewed September 5, 2005]"

,annotation={

	First posting showing how RCU can be safely adapted for
@@ -1256,7 +1256,7 @@ Oregon Health and Sciences University" 
,year="2005"

,day="18"

,note="Available:

\url{http://lkml.org/lkml/2005/3/18/122}

\url{https://lore.kernel.org/r/Pine.OSF.4.05.10503181336310.2466-100000@da410.phys.au.dk}

[Viewed March 30, 2006]"

,annotation={

	Esben Neilsen suggests read-side suppression of grace-period
@@ -1302,7 +1302,7 @@ Data Structures" 
,month="May"

,year="2005"

,note="Available:

\url{http://lkml.org/lkml/2005/5/9/185}

\url{https://lore.kernel.org/r/20050510012444.GA3011@us.ibm.com}

[Viewed May 13, 2005]"

,annotation={

	First publication of working lock-based deferred free patches
@@ -1385,7 +1385,7 @@ Data Structures" 
,day="1"

,year="2005"

,note="Available:

\url{http://lkml.org/lkml/2005/8/1/155}

\url{https://lore.kernel.org/r/20050801171137.GA1754@us.ibm.com}

[Viewed March 14, 2006]"

,annotation={

	First operating counter-based realtime RCU patch posted to LKML.
@@ -1399,7 +1399,7 @@ Data Structures" 
,day="8"

,year="2005"

,note="Available:

\url{http://lkml.org/lkml/2005/8/8/108}

\url{https://lore.kernel.org/r/20050808144216.GA1307@us.ibm.com}

[Viewed March 14, 2006]"

,annotation={

	First operating counter-based realtime RCU patch posted to LKML,
@@ -1415,7 +1415,7 @@ Data Structures" 
,day="1"

,year="2005"

,note="Available:

\url{http://lkml.org/lkml/2005/10/1/70}

\url{https://lore.kernel.org/r/20051001182056.GA1613@us.ibm.com}

[Viewed March 14, 2006]"

,annotation={

	First rcutorture patch.
@@ -1429,7 +1429,7 @@ Data Structures" 
,day="6"

,year="2006"

,note="Available:

\url{https://lkml.org/lkml/2006/1/7/22}

\url{https://lore.kernel.org/r/20060106.231054.43576567.davem@davemloft.net}

[Viewed February 29, 2012]"

,annotation={

	David Miller's view on hashed arrays of locks: used to really
@@ -1464,7 +1464,7 @@ Distributed Processing Symposium" 
,day="20"

,year="2006"

,note="Available:

\url{http://lkml.org/lkml/2006/6/20/238}

\url{https://lore.kernel.org/r/20060408134707.22479.33814.sendpatchset@linux.site}

[Viewed March 25, 2008]"

,annotation={

	RCU-protected radix tree.
@@ -1554,7 +1554,7 @@ Revised: 
,day="28"

,year="2006"

,note="Available:

\url{http://lkml.org/lkml/2006/9/28/160}

\url{https://lore.kernel.org/r/20060928142616.GA20185@infradead.org}

[Viewed March 27, 2008]"

}
@@ -1593,7 +1593,7 @@ Revised: 
,year="2006"

,day=26

,note="Available:

\url{http://lkml.org/lkml/2006/10/26/73}

\url{https://lore.kernel.org/r/20061026105731.GE11803@in.ibm.com}

[Viewed January 26, 2009]"

,annotation={

	RCU-based reader-writer lock that allows readers to proceed with
@@ -1612,12 +1612,12 @@ Revised: 
,year="2006"

,day=17

,note="Available:

\url{http://lkml.org/lkml/2006/11/17/56}

\url{https://lore.kernel.org/r/20061117092925.GT7164@kernel.dk}

[Viewed May 28, 2007]"

,annotation={

	SRCU's grace periods are too slow for Jens, even after a

	factor-of-three speedup.

	Sped-up version of SRCU at http://lkml.org/lkml/2006/11/17/359.

	Sped-up version of SRCU at https://lore.kernel.org/r/20061118002845.GF2632@us.ibm.com.

}

}
@@ -1629,7 +1629,7 @@ Revised: 
,year="2006"

,day=19

,note="Available:

\url{http://lkml.org/lkml/2006/11/19/69}

\url{https://lore.kernel.org/r/20061119190027.GA3676@oleg}

[Viewed May 28, 2007]"

,annotation={

	First cut of QRCU.  Expanded/corrected versions followed.
@@ -1644,7 +1644,7 @@ Revised: 
,year="2006"

,day=30

,note="Available:

\url{http://lkml.org/lkml/2006/11/29/330}

\url{https://lore.kernel.org/r/20061130015714.GC1350@oleg}

[Viewed November 26, 2008]"

,annotation={

	Expanded/corrected version of QRCU.
@@ -1709,7 +1709,7 @@ Revised: 
,year="2007"

,day=3

,note="Available:

\url{http://lkml.org/lkml/2007/1/3/112}

\url{https://lore.kernel.org/r/20070103152738.GA16063@localdomain}

[Viewed May 28, 2007]"

,annotation={

	Patch for list_splice_rcu().
@@ -1737,7 +1737,7 @@ Revised: 
,year="2007"

,day=28

,note="Available:

\url{http://lkml.org/lkml/2007/1/28/34}

\url{https://lore.kernel.org/r/20070128120509.719287000@programming.kicks-ass.net}

[Viewed March 27, 2008]"

,annotation={

	RCU-like implementation for frequent updaters and rare readers(!).
@@ -1767,7 +1767,7 @@ Revised: 
,year="2007"

,day=24

,note="Available:

\url{http://lkml.org/lkml/2007/2/25/18}

\url{https://lore.kernel.org/r/20070225062349.GA17468@linux.vnet.ibm.com}

[Viewed March 27, 2008]"

,annotation={

	Patch for QRCU supplying lock-free fast path.
@@ -1846,7 +1846,7 @@ Revised: 
,annotation={

	LWN article describing Promela and spin, and also using Oleg

	Nesterov's QRCU as an example (with Paul McKenney's fastpath).

	Merged patch at: http://lkml.org/lkml/2007/2/25/18

	Merged patch at: https://lore.kernel.org/r/20070225062349.GA17468@linux.vnet.ibm.com

}

}
@@ -1885,7 +1885,7 @@ Revised: 
,day="10"

,year="2007"

,note="Available:

\url{http://lkml.org/lkml/2007/9/10/213}

\url{https://lore.kernel.org/r/20070910183004.GA3299@linux.vnet.ibm.com}

[Viewed October 25, 2007]"

,annotation={

	Final patch for preemptable RCU to -rt.  (Later patches were
@@ -1933,7 +1933,7 @@ Revised: 
,day="20"

,year="2007"

,note="Available:

\url{http://lkml.org/lkml/2007/12/20/244}

\url{https://lore.kernel.org/r/20071220142540.GB22523@Krystal}

[Viewed March 27, 2008]"

,annotation={

	Request for call_rcu_sched() and rcu_barrier_sched().
@@ -2013,7 +2013,7 @@ Revised: 
,day="29"

,year="2008"

,note="Available:

\url{http://lkml.org/lkml/2008/1/29/208}

\url{https://lore.kernel.org/r/Pine.LNX.4.58.0801291113350.20371@gandalf.stny.rr.com}

[Viewed March 27, 2008]"

,annotation={

	Patch that prevents preemptible RCU from unnecessarily waking
@@ -2028,7 +2028,7 @@ Revised: 
,day="1"

,year="2008"

,note="Available:

\url{http://lkml.org/lkml/2008/2/2/255}

\url{https://lore.kernel.org/r/20080202214124.GA28612@linux.vnet.ibm.com}

[Viewed October 18, 2008]"

,annotation={

	Explanation of compilers violating dependency ordering.
@@ -2088,7 +2088,7 @@ lot of {Linux} into your technology!!!" 
,day="3"

,year="2008"

,note="Available:

\url{http://lkml.org/lkml/2008/6/2/539}

\url{https://lore.kernel.org/r/4844BE83.5010401@cn.fujitsu.com}

[Viewed December 10, 2008]"

,annotation={

	Updated RCU classic algorithm.  Introduced multi-tailed list
@@ -2122,7 +2122,7 @@ lot of {Linux} into your technology!!!" 
,day="21"

,year="2008"

,note="Available:

\url{http://lkml.org/lkml/2008/8/21/336}

\url{https://lore.kernel.org/r/48AD8969.7060900@colorfullife.com}

[Viewed December 8, 2008]"

,annotation={

	State-based RCU.  One key thing that this patch does is to
@@ -2137,7 +2137,7 @@ lot of {Linux} into your technology!!!" 
,day="6"

,year="2008"

,note="Available:

\url{http://lkml.org/lkml/2008/9/6/86}

\url{https://lore.kernel.org/r/48C2B1D2.5070801@colorfullife.com}

[Viewed December 8, 2008]"

,annotation={

	Manfred notes a fix required to my attempt to separate irq
@@ -2183,7 +2183,7 @@ lot of {Linux} into your technology!!!" 
,day="14"

,year="2009"

,note="Available:

\url{http://lkml.org/lkml/2009/1/14/449}

\url{https://lore.kernel.org/r/20090114202044.GJ6734@linux.vnet.ibm.com}

[Viewed January 15, 2009]"

,annotation={

	Small-footprint implementation of RCU for uniprocessor
@@ -2218,7 +2218,7 @@ lot of {Linux} into your technology!!!" 
	git://lttng.org/userspace-rcu.git

	http://lttng.org/cgi-bin/gitweb.cgi?p=userspace-rcu.git

	http://lttng.org/urcu

	http://lkml.org/lkml/2009/2/5/572

	https://lore.kernel.org/r/20090206030543.GB8560@Krystal

}

}
@@ -2258,7 +2258,7 @@ lot of {Linux} into your technology!!!" 
,day="25"

,year="2009"

,note="Available:

\url{http://lkml.org/lkml/2009/6/25/306}

\url{https://lore.kernel.org/r/20090625160706.GA9467@linux.vnet.ibm.com}

[Viewed August 16, 2009]"

,annotation={

	First posting of expedited RCU to be accepted into -tip.
@@ -2272,7 +2272,7 @@ lot of {Linux} into your technology!!!" 
,day="23"

,year="2009"

,note="Available:

\url{http://lkml.org/lkml/2009/7/23/294}

\url{https://lore.kernel.org/r/20090724001429.GA17374@linux.vnet.ibm.com}

[Viewed August 15, 2009]"

,annotation={

	First posting of simple and fast preemptable RCU.
@@ -2350,7 +2350,7 @@ lot of {Linux} into your technology!!!" 
,month="December"

,year="2009"

,note="Available:

\url{http://lkml.org/lkml/2009/10/18/129}

\url{https://lore.kernel.org/r/20091018232918.GA7385@Krystal}

[Viewed December 29, 2009]"

,annotation={

	Mathieu proposed defer_rcu() with fixed-size per-thread pool
@@ -2518,7 +2518,7 @@ lot of {Linux} into your technology!!!" 
,month="January"

,year="2011"

,note="Available:

\url{https://lkml.org/lkml/2011/1/18/322}

\url{https://lore.kernel.org/r/AANLkTimajU0x1v6y3rH2+jr-bZ=tNLs1S_agXdGGAa3S@mail.gmail.com}

[Viewed March 4, 2011]"

,annotation={

	"The RCU-based name lookup is at the other end of the spectrum - the

Documentation/accounting/cgroupstats.rst

+2 −2
Original line number Diff line number Diff line
@@ -3,8 +3,8 @@ Control Groupstats 
==================



Control Groupstats is inspired by the discussion at

http://lkml.org/lkml/2007/4/11/187 and implements per cgroup statistics as

suggested by Andrew Morton in http://lkml.org/lkml/2007/4/11/263.

https://lore.kernel.org/r/461CF883.2030308@sw.ru and implements per cgroup statistics as

suggested by Andrew Morton in https://lore.kernel.org/r/20070411114927.1277d7c9.akpm@linux-foundation.org.



Per cgroup statistics infrastructure re-uses code from the taskstats

interface. A new set of cgroup operations are registered with commands

Documentation/admin-guide/README.rst

+4 −3
Original line number Diff line number Diff line
@@ -226,9 +226,10 @@ Configuring the kernel 
                           all module options to built in (=y) options. You can

                           also preserve modules by LMC_KEEP.



     "make kvmconfig"   Enable additional options for kvm guest kernel support.

     "make kvm_guest.config"   Enable additional options for kvm guest kernel

                               support.



     "make xenconfig"   Enable additional options for xen dom0 guest kernel

     "make xen.config"   Enable additional options for xen dom0 guest kernel

                         support.



     "make tinyconfig"  Configure the tiniest possible kernel.

Documentation/admin-guide/cgroup-v1/memory.rst

+7 −7
Original line number Diff line number Diff line
@@ -963,21 +963,21 @@ References 
2. Singh, Balbir. Memory Controller (RSS Control),

   http://lwn.net/Articles/222762/

3. Emelianov, Pavel. Resource controllers based on process cgroups

   http://lkml.org/lkml/2007/3/6/198

   https://lore.kernel.org/r/45ED7DEC.7010403@sw.ru

4. Emelianov, Pavel. RSS controller based on process cgroups (v2)

   http://lkml.org/lkml/2007/4/9/78

   https://lore.kernel.org/r/461A3010.90403@sw.ru

5. Emelianov, Pavel. RSS controller based on process cgroups (v3)

   http://lkml.org/lkml/2007/5/30/244

   https://lore.kernel.org/r/465D9739.8070209@openvz.org

6. Menage, Paul. Control Groups v10, http://lwn.net/Articles/236032/

7. Vaidyanathan, Srinivasan, Control Groups: Pagecache accounting and control

   subsystem (v3), http://lwn.net/Articles/235534/

8. Singh, Balbir. RSS controller v2 test results (lmbench),

   http://lkml.org/lkml/2007/5/17/232

   https://lore.kernel.org/r/464C95D4.7070806@linux.vnet.ibm.com

9. Singh, Balbir. RSS controller v2 AIM9 results

   http://lkml.org/lkml/2007/5/18/1

   https://lore.kernel.org/r/464D267A.50107@linux.vnet.ibm.com

10. Singh, Balbir. Memory controller v6 test results,

    http://lkml.org/lkml/2007/8/19/36

    https://lore.kernel.org/r/20070819094658.654.84837.sendpatchset@balbir-laptop

11. Singh, Balbir. Memory controller introduction (v6),

    http://lkml.org/lkml/2007/8/17/69

    https://lore.kernel.org/r/20070817084228.26003.12568.sendpatchset@balbir-laptop

12. Corbet, Jonathan, Controlling memory use in cgroups,

    http://lwn.net/Articles/243795/

Documentation/admin-guide/cgroup-v2.rst

+34 −30
Original line number Diff line number Diff line 
.. _cgroup-v2:



================

Control Group v2

================
@@ -172,7 +174,6 @@ disabling controllers in v1 and make them always available in v2. 
cgroup v2 currently supports the following mount options.



  nsdelegate



	Consider cgroup namespaces as delegation boundaries.  This

	option is system wide and can only be set on mount or modified

	through remount from the init namespace.  The mount option is
@@ -180,7 +181,6 @@ cgroup v2 currently supports the following mount options. 
	Delegation section for details.



  memory_localevents



        Only populate memory.events with data for the current cgroup,

        and not any subtrees. This is legacy behaviour, the default

        behaviour without this option is to include subtree counts.
@@ -189,7 +189,6 @@ cgroup v2 currently supports the following mount options. 
        option is ignored on non-init namespace mounts.



  memory_recursiveprot



        Recursively apply memory.min and memory.low protection to

        entire subtrees, without requiring explicit downward

        propagation into leaf cgroups.  This allows protecting entire
@@ -786,7 +785,6 @@ Core Interface Files 
All cgroup core files are prefixed with "cgroup."



  cgroup.type



	A read-write single value file which exists on non-root

	cgroups.
@@ -954,6 +952,8 @@ All cgroup core files are prefixed with "cgroup." 
Controllers

===========



.. _cgroup-v2-cpu:



CPU

---
@@ -1260,8 +1260,8 @@ PAGE_SIZE multiple when read back. 
	fixed position; use the keys to look up specific values!



	If the entry has no per-node counter (or not show in the

	mempry.numa_stat). We use 'npn'(non-per-node) as the tag

	to indicate that it will not show in the mempry.numa_stat.

	memory.numa_stat). We use 'npn' (non-per-node) as the tag

	to indicate that it will not show in the memory.numa_stat.



	  anon

		Amount of memory used in anonymous mappings such as
@@ -1558,7 +1558,7 @@ IO Interface Files 
	  8:0 rbytes=90430464 wbytes=299008000 rios=8950 wios=1252 dbytes=50331648 dios=3021



  io.cost.qos

	A read-write nested-keyed file with exists only on the root

	A read-write nested-keyed file which exists only on the root

	cgroup.



	This file configures the Quality of Service of the IO cost
@@ -1613,7 +1613,7 @@ IO Interface Files 
	automatic mode can be restored by setting "ctrl" to "auto".



  io.cost.model

	A read-write nested-keyed file with exists only on the root

	A read-write nested-keyed file which exists only on the root

	cgroup.



	This file configures the cost model of the IO cost model based
@@ -2002,8 +2002,10 @@ Cpuset Interface Files 


	It accepts only the following input values when written to.



        "root"   - a partition root

        "member" - a non-root member of a partition

	  ========	================================

	  "root"	a partition root

	  "member"	a non-root member of a partition

	  ========	================================



	When set to be a partition root, the current cgroup is the

	root of a new partition or scheduling domain that comprises
@@ -2044,9 +2046,11 @@ Cpuset Interface Files 
	root to change.  On read, the "cpuset.sched.partition" file

	can show the following values.



	  ==============	==============================

	  "member"		Non-root member of a partition

	  "root"		Partition root

	  "root invalid"	Invalid partition root

	  ==============	==============================



	It is a partition root if the first 2 partition root conditions

	above are true and at least one CPU from "cpuset.cpus" is
@@ -2219,7 +2223,7 @@ Without cgroup namespace, the "/proc/$PID/cgroup" file shows the 
complete path of the cgroup of a process.  In a container setup where

a set of cgroups and namespaces are intended to isolate processes the

"/proc/$PID/cgroup" file may leak potential system level information

to the isolated processes.  For Example::

to the isolated processes.  For example::



  # cat /proc/self/cgroup

  0::/batchjobs/container_id1