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ftrace: Use asynchronous grace period for register_ftrace_direct()

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When running heavy test workloads with KASAN enabled, RCU Tasks grace
periods can extend for many tens of seconds, significantly slowing
trace registration.  Therefore, make the registration-side RCU Tasks
grace period be asynchronous via call_rcu_tasks().

Link: https://lore.kernel.org/linux-trace-kernel/ac05be77-2972-475b-9b57-56bef15aa00a@paulmck-laptop

Reported-by: Jakub Kicinski <kuba@kernel.org>
Reported-by: Alexei Starovoitov <ast@kernel.org>
Reported-by: Chris Mason <clm@fb.com>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
This commit is contained in:
Paul E. McKenney 2024-05-01 16:12:37 -07:00 committed by Steven Rostedt (Google)
parent c5963a0990
commit 33f137143e
1 changed files with 9 additions and 4 deletions
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13
kernel/trace/ftrace.c
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@ -5366,6 +5366,13 @@ static void remove_direct_functions_hash(struct ftrace_hash *hash, unsigned long
}
}
static void register_ftrace_direct_cb(struct rcu_head *rhp)
{
struct ftrace_hash *fhp = container_of(rhp, struct ftrace_hash, rcu);
free_ftrace_hash(fhp);
}
/**
* register_ftrace_direct - Call a custom trampoline directly
* for multiple functions registered in @ops
@ -5464,10 +5471,8 @@ int register_ftrace_direct(struct ftrace_ops *ops, unsigned long addr)
out_unlock:
mutex_unlock(&direct_mutex);
if (free_hash && free_hash != EMPTY_HASH) {
synchronize_rcu_tasks();
free_ftrace_hash(free_hash);
}
if (free_hash && free_hash != EMPTY_HASH)
call_rcu_tasks(&free_hash->rcu, register_ftrace_direct_cb);
if (new_hash)
free_ftrace_hash(new_hash);