[tip:perf/core] perf: Fix documentation for sysctls perf_event_paranoid and perf_event_mlock_kb
From: tip-bot for Konstantin Khlebnikov
Date: Thu Aug 24 2017 - 04:32:10 EST
Commit-ID: ac0bb6b72f4bbab08f270a919406d971e73698b5
Gitweb: http://git.kernel.org/tip/ac0bb6b72f4bbab08f270a919406d971e73698b5
Author: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx>
AuthorDate: Sun, 20 Aug 2017 14:39:20 +0300
Committer: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Tue, 22 Aug 2017 13:24:54 -0300
perf: Fix documentation for sysctls perf_event_paranoid and perf_event_mlock_kb
Fix misprint CAP_IOC_LOCK -> CAP_IPC_LOCK. This capability have nothing
to do with raw tracepoints. This part is about bypassing mlock limits.
Sysctl kernel.perf_event_paranoid = -1 allows raw and ftrace function
tracepoints without CAP_SYS_ADMIN.
Signed-off-by: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/150322916080.129746.11285255474738558340.stgit@buzz
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
Documentation/sysctl/kernel.txt | 13 ++++++++++++-
tools/perf/util/evsel.c | 4 +++-
2 files changed, 15 insertions(+), 2 deletions(-)
diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt
index bac23c1..ce61d1f 100644
--- a/Documentation/sysctl/kernel.txt
+++ b/Documentation/sysctl/kernel.txt
@@ -61,6 +61,7 @@ show up in /proc/sys/kernel:
- perf_cpu_time_max_percent
- perf_event_paranoid
- perf_event_max_stack
+- perf_event_mlock_kb
- perf_event_max_contexts_per_stack
- pid_max
- powersave-nap [ PPC only ]
@@ -654,7 +655,9 @@ Controls use of the performance events system by unprivileged
users (without CAP_SYS_ADMIN). The default value is 2.
-1: Allow use of (almost) all events by all users
->=0: Disallow raw tracepoint access by users without CAP_IOC_LOCK
+ Ignore mlock limit after perf_event_mlock_kb without CAP_IPC_LOCK
+>=0: Disallow ftrace function tracepoint by users without CAP_SYS_ADMIN
+ Disallow raw tracepoint access by users without CAP_SYS_ADMIN
>=1: Disallow CPU event access by users without CAP_SYS_ADMIN
>=2: Disallow kernel profiling by users without CAP_SYS_ADMIN
@@ -673,6 +676,14 @@ The default value is 127.
==============================================================
+perf_event_mlock_kb:
+
+Control size of per-cpu ring buffer not counted agains mlock limit.
+
+The default value is 512 + 1 page
+
+==============================================================
+
perf_event_max_contexts_per_stack:
Controls maximum number of stack frame context entries for
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 5dfb8bc..a5888c7 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -2674,7 +2674,9 @@ int perf_evsel__open_strerror(struct perf_evsel *evsel, struct target *target,
"unprivileged users (without CAP_SYS_ADMIN).\n\n"
"The current value is %d:\n\n"
" -1: Allow use of (almost) all events by all users\n"
- ">= 0: Disallow raw tracepoint access by users without CAP_IOC_LOCK\n"
+ " Ignore mlock limit after perf_event_mlock_kb without CAP_IPC_LOCK\n"
+ ">= 0: Disallow ftrace function tracepoint by users without CAP_SYS_ADMIN\n"
+ " Disallow raw tracepoint access by users without CAP_SYS_ADMIN\n"
">= 1: Disallow CPU event access by users without CAP_SYS_ADMIN\n"
">= 2: Disallow kernel profiling by users without CAP_SYS_ADMIN\n\n"
"To make this setting permanent, edit /etc/sysctl.conf too, e.g.:\n\n"