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ftrace: Prevent RCU stall on PREEMPT_VOLUNTARY kernels

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The function match_records() may take a while due to a large
number of string comparisons, so when in PREEMPT_VOLUNTARY
kernels we could face RCU stalls due to that.

Add a cond_resched() to prevent that.

Link: https://lkml.kernel.org/r/20221115204847.593616-1-gpiccoli@igalia.com

Cc: Mark Rutland <mark.rutland@arm.com>
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Paul E. McKenney <paulmck@kernel.org> # from RCU CPU stall warning perspective
Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
This commit is contained in:
Guilherme G. Piccoli 2022-11-15 17:48:47 -03:00 committed by Steven Rostedt (Google)
parent fb9f5ee9bf
commit d0b24b4e91
1 changed files with 1 additions and 0 deletions
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kernel/trace/ftrace.c
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@ -4204,6 +4204,7 @@ match_records(struct ftrace_hash *hash, char *func, int len, char *mod)
} }
found = 1; found = 1;
} }
cond_resched();
} while_for_each_ftrace_rec(); } while_for_each_ftrace_rec();
out_unlock: out_unlock:
mutex_unlock(&ftrace_lock); mutex_unlock(&ftrace_lock);