Commit 543487c7a2670bb0d96c00673a44b74360e3b6c1
Committed by
Frederic Weisbecker
1 parent
3b2f64d00c
Exists in
master
and in
20 other branches
nohz: Do not warn about unstable tsc unless user uses nohz_full
If the user enables CONFIG_NO_HZ_FULL and runs the kernel on a machine with an unstable TSC, it will produce a WARN_ON dump as well as taint the kernel. This is a bit extreme for a kernel that just enables a feature but doesn't use it. The warning should only happen if the user tries to use the feature by either adding nohz_full to the kernel command line, or by enabling CONFIG_NO_HZ_FULL_ALL that makes nohz used on all CPUs at boot up. Note, this second feature should not (yet) be used by distros or anyone that doesn't care if NO_HZ is used or not. Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Li Zhong <zhong@linux.vnet.ibm.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Kevin Hilman <khilman@linaro.org> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Showing 1 changed file with 2 additions and 1 deletions Side-by-side Diff
kernel/time/tick-sched.c
... | ... | @@ -182,7 +182,8 @@ |
182 | 182 | * Don't allow the user to think they can get |
183 | 183 | * full NO_HZ with this machine. |
184 | 184 | */ |
185 | - WARN_ONCE(1, "NO_HZ FULL will not work with unstable sched clock"); | |
185 | + WARN_ONCE(have_nohz_full_mask, | |
186 | + "NO_HZ FULL will not work with unstable sched clock"); | |
186 | 187 | return false; |
187 | 188 | } |
188 | 189 | #endif |