This is a requirement to create real callchain entries for inlined
frames.

Since the list of inlines usually contains the target symbol too, i.e.
the location where the frames get inlined to, we alias that symbol and
reuse it as-is is. This ensures that other dependent functionality keeps
working, most notably annotation of the target frames.

For all other entries in the inline_list, a fake symbol is created.
These are marked by new 'inlined' member which is set to true. Only
those symbols are managed by the inline_list and get freed when the
inline_list is deleted from within inline_node__delete.
Signed-off-by: Milian Wolff <milian.wolff@kdab.com>
Reviewed-by: Jiri Olsa <jolsa@redhat.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Yao Jin <yao.jin@linux.intel.com>
Link: http://lkml.kernel.org/r/20171009203310.17362-4-milian.wolff@kdab.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

This is mostly a preparation to enable the creation of full callchain
nodes for inline frames. Such frames will reference the IP of the
non-inlined frame, but hold the symbol and srcline for an inlined
location. As such, we won't be able to query the srcline on-demand based
on the IP alone. Instead, we will leverage the functionality provided by
this patch here, and store the srcline for the inlined nodes in the new
srcline member of callchain_cursor_node.

Note that this patch on its own leaks the srcline, as there is no
free_callchain_cursor_node or similar. A future patch will add caching
of the srcline and handle deletion properly.
Signed-off-by: Milian Wolff <milian.wolff@kdab.com>
Reviewed-by: Jiri Olsa <jolsa@redhat.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Yao Jin <yao.jin@linux.intel.com>
Link: http://lkml.kernel.org/r/20171009203310.17362-3-milian.wolff@kdab.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

The follow-up commits will make inline frames first-class citizens in
the callchain, thereby obsoleting all of this special code.
Signed-off-by: Milian Wolff <milian.wolff@kdab.com>
Reviewed-by: Jiri Olsa <jolsa@redhat.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Yao Jin <yao.jin@linux.intel.com>
Link: http://lkml.kernel.org/r/20171009203310.17362-2-milian.wolff@kdab.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Merge tag 'perf-core-for-mingo-4.15-20171023' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/core

Pull perf/core improvements and fixes from Arnaldo Carvalho de Melo:

 - Update vendor events JSON metrics for Intel's Broadwell, Broadwell
   Server, Haswell, Haswell Server, IvyBridge, IvyTown, JakeTown, Sandy
   Bridge, Skylake and SkyLake Server (Andi Kleen)

 - Add vendor event file for Intel's Goldmont Plus V1 (Kan Liang)

 - Move perf_mmap methods from 'perf record' and evlist.c to a separate
   mmap.[ch] pair, to better separate things and pave the way for further
   work on multithreading tools (Arnaldo Carvalho de Melo)

 - Do not check ABI headers in a detached tarball build, as it the kernel
   headers from where we copied tools/include/ are by definition not
   available (Arnaldo Carvalho de Melo)

 - Make 'perf script' use fprintf() like printing, i.e. receiving a FILE
   pointer so that it gets consistent with other tools/ code and allows
   for printing to per-event files (Arnaldo Carvalho de Melo)

 - Error handling fixes (resource release on exit) for 'perf script'
   and 'perf kmem' (Christophe JAILLET)

 - Make some 'perf event attr' tests optional on virtual machines, where
   tested counters are not available (Jiri Olsa)
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Add a Intel event file for perf.
Signed-off-by: Kan Liang <Kan.liang@intel.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/1508331907-395162-1-git-send-email-kan.liang@intel.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

We don't need perf.h, that is a kitchen sink, all we need is
perf_events.h for perf_ns_link_info, sys/types.h for pid_t and
linux/types.h for u64, list_head.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Li Zhijian <lizhijian@cn.fujitsu.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-f2uxyaj4s2hmntkrezpa6dqz@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

If the string passed in '--time' is invalid, we must do some cleanup
before leaving. As in the other error handling paths of this function.
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: kernel-janitors@vger.kernel.org
Fixes: 2a865bd8 ("perf kmem: Add option to specify time window of interest")
Link: http://lkml.kernel.org/r/20170916060936.28199-1-christophe.jaillet@wanadoo.frSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

If the string passed in '--time' is invalid, or if failed to set
libtraceevent function resolver, we must do some cleanup before leaving.
As in the other error handling paths of this function.
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: kernel-janitors@vger.kernel.org
Link: http://lkml.kernel.org/r/20170916062537.28921-1-christophe.jaillet@wanadoo.frSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

We've been mixing print() with fprintf() style printing for a while, but
now we need to use fprintf() like syntax uniformly as a preparatory
patch for supporting printing to different files, one per event.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: yuzhoujian <yuzhoujian@didichuxing.com>
Link: http://lkml.kernel.org/n/tip-kv5z3v8ptfghbarv3a9usvin@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Out of print_binary() but receiving a fp pointer and expecting that the
printer be a fprintf like function, i.e. receive a FILE pointer and
return the number of characters printed.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: yuzhoujian <yuzhoujian@didichuxing.com>
Link: http://lkml.kernel.org/n/tip-6oqnxr6lmgqe6q6p3iugnscx@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Some of the metrics use an incorrect syntax for specifying the cmask for
an event. Convert to perf syntax so that they can be resolved.

Fixes metrics on Broadwell, SandyBridge.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/n/tip-3k3fkfj8obek9dkmryyrqzhu@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

When we use one of:

  [acme@jouet linux]$ make help | grep perf
    perf-tar-src-pkg    - Build perf-4.14.0-rc3.tar source tarball
    perf-targz-src-pkg  - Build perf-4.14.0-rc3.tar.gz source tarball
    perf-tarbz2-src-pkg - Build perf-4.14.0-rc3.tar.bz2 source tarball
    perf-tarxz-src-pkg  - Build perf-4.14.0-rc3.tar.xz source tarball
  [acme@jouet linux]$

I.e. when we create a detached tarball to build perf outside outside the
enveloping kernel sources (from a kernel tarball or a checked out
linux.git directory) we by definition can't check for differences among
the tools/{include,arch}, etc files we originally copied from the
kernel, so bail out in that case, to avoid warnings when doing the
detached builds.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-vbrga0mhplv7niwxr3ghjyxv@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

There's no need for extra cpuid_parse arch callback, it can be handled
directly in init callback.

Adding the init function to x86 to cover the cpuid initialization.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20171011150158.11895-2-jolsa@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Fix an incorrect description in the 'perf list' manpage. When a group
does not fit into the hardware it is partially scheduled, but does not
error out.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Link: http://lkml.kernel.org/r/20171010224322.15861-1-andi@firstfloor.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Otherwise we fail on virtual machines with no support for specific HW
events.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20171009130712.14747-1-jolsa@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

The previous prep patch was just to show exactly what changed in that
function, now its time to move that method and things only it uses to
the right place, mmap.[ch]

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-aaxywfgw3d44x6xlu8zm1avu@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

It becomes a perf_mmap method, "push", that build reads from a mmap and
"pushes" it to a consumer, that in the initial case, for 'perf record',
just writes it to the perf.data file descriptor, but may be used by
'top', etc.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-u4l1qjbi6l76r2k0nv99220n@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

To better organize the sources, and we may end up even using it
directly, without evlists and evsels.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-oiqrm7grflurnnzo2ovfnslg@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/20170914200748.GA13837@tassilo.jf.intel.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/20170914200748.GA13837@tassilo.jf.intel.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/20170914200748.GA13837@tassilo.jf.intel.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/20170914200748.GA13837@tassilo.jf.intel.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/20170914200748.GA13837@tassilo.jf.intel.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/20170914200748.GA13837@tassilo.jf.intel.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/20170914200748.GA13837@tassilo.jf.intel.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/20170914200748.GA13837@tassilo.jf.intel.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/20170914200748.GA13837@tassilo.jf.intel.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/20170914200748.GA13837@tassilo.jf.intel.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

The jprobes subsystem is being removed, so convert to using kprobes instead.
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20171020133127.GA18360@beastSigned-off-by: Ingo Molnar <mingo@kernel.org>

Remove jprobes related documentation from kprobes.txt.

Also add some migration advice for the people who are
still using jprobes.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: David S . Miller <davem@davemloft.net>
Cc: Ian McDonald <ian.mcdonald@jandi.co.nz>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E . McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlad Yasevich <vyasevich@gmail.com>
Link: http://lkml.kernel.org/r/150724539698.5014.7300022363980503141.stgit@devbox
[ Fixes to the new documentation. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Remove the jprobes sample module because jprobes are deprecated.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: David S . Miller <davem@davemloft.net>
Cc: Ian McDonald <ian.mcdonald@jandi.co.nz>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E . McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlad Yasevich <vyasevich@gmail.com>
Link: http://lkml.kernel.org/r/150724535709.5014.7261513316230565780.stgit@devboxSigned-off-by: Ingo Molnar <mingo@kernel.org>

Disable jprobes test code because jprobes are deprecated.
This code will be completely removed when the jprobe code
is removed.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: David S . Miller <davem@davemloft.net>
Cc: Ian McDonald <ian.mcdonald@jandi.co.nz>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E . McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlad Yasevich <vyasevich@gmail.com>
Link: http://lkml.kernel.org/r/150724531730.5014.6377596890962355763.stgit@devboxSigned-off-by: Ingo Molnar <mingo@kernel.org>

Disable the jprobes APIs and comment out the jprobes API function
code. This is in preparation of removing all jprobes related
code (including kprobe's break_handler).

Nowadays ftrace and other tracing features are mature enough
to replace jprobes use-cases. Users can safely use ftrace and
perf probe etc. for their use cases.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: David S . Miller <davem@davemloft.net>
Cc: Ian McDonald <ian.mcdonald@jandi.co.nz>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E . McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlad Yasevich <vyasevich@gmail.com>
Link: http://lkml.kernel.org/r/150724527741.5014.15465541485637899227.stgit@devboxSigned-off-by: Ingo Molnar <mingo@kernel.org>

Signed-off-by: Ingo Molnar <mingo@kernel.org>

We want to wait for all potentially preempted kprobes trampoline
execution to have completed. This guarantees that any freed
trampoline memory is not in use by any task in the system anymore.
synchronize_rcu_tasks() gives such a guarantee, so use it.

Also, this guarantees to wait for all potentially preempted tasks
on the instructions which will be replaced with a jump.

Since this becomes a problem only when CONFIG_PREEMPT=y, enable
CONFIG_TASKS_RCU=y for synchronize_rcu_tasks() in that case.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Naveen N . Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Paul E . McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/150845661962.5443.17724352636247312231.stgit@devboxSigned-off-by: Ingo Molnar <mingo@kernel.org>

Merge tag 'perf-urgent-for-mingo-4.14-20171019' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/urgent

Pull perf/urgent fixes from Arnaldo Carvalho de Melo:

- Fix crash in perf_hpp__reset_output_field() (Jiri Olsa)

- Fix eBPF file/vendor events ambiguity in event specification (Jiri Olsa)

- Fix closing evsel fd in 'perf stat' (Jin Yao)

- Make perf test shell trace+probe_libc_inet_pton.sh pass in Debian/Ubuntu (Li Zhijian)

- Fix 'perf buildid-list --with-hits' crash when processing PERF_RECORD_NAMESPACE (Namhyung Kim)

- Fix documentation for an inexistent option 'perf record -l' (Taeung Song)

- Add long time reviewers to MAINTAINERS (Arnaldo Carvalho de Melo)
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Pull power management fix from Rafael Wysocki:
 "This reverts a problematic commit modifying the turbostat utility that
  went in during the 4.13 cycle (Len Brown)"

* tag 'pm-4.14-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  Revert "tools/power turbostat: stop migrating, unless '-m'"

Because many of RCU's files have not been included into docbook, a
number of errors have accumulated.  This commit fixes them.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Commit 764f8079 ("doc: Add RCU files to docbook-generation files")
added :external: options for RCU source files in the file
Documentation/core-api/kernel-api.rst.  However, this now means nothing,
so this commit removes them.
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: Akira Yokosawa <akiyks@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

This introduces a "register private expedited" membarrier command which
allows eventual removal of important memory barrier constraints on the
scheduler fast-paths. It changes how the "private expedited" membarrier
command (new to 4.14) is used from user-space.

This new command allows processes to register their intent to use the
private expedited command.  This affects how the expedited private
command introduced in 4.14-rc is meant to be used, and should be merged
before 4.14 final.

Processes are now required to register before using
MEMBARRIER_CMD_PRIVATE_EXPEDITED, otherwise that command returns EPERM.

This fixes a problem that arose when designing requested extensions to
sys_membarrier() to allow JITs to efficiently flush old code from
instruction caches.  Several potential algorithms are much less painful
if the user register intent to use this functionality early on, for
example, before the process spawns the second thread.  Registering at
this time removes the need to interrupt each and every thread in that
process at the first expedited sys_membarrier() system call.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>