diff options
| -rw-r--r-- | Documentation/trace/kprobes.rst | 3 | ||||
| -rw-r--r-- | kernel/kprobes.c | 8 |
2 files changed, 3 insertions, 8 deletions
diff --git a/Documentation/trace/kprobes.rst b/Documentation/trace/kprobes.rst index 48cf778a2468..fc7ce76eab65 100644 --- a/Documentation/trace/kprobes.rst +++ b/Documentation/trace/kprobes.rst @@ -131,8 +131,7 @@ For example, if the function is non-recursive and is called with a spinlock held, maxactive = 1 should be enough. If the function is non-recursive and can never relinquish the CPU (e.g., via a semaphore or preemption), NR_CPUS should be enough. If maxactive <= 0, it is -set to a default value. If CONFIG_PREEMPT is enabled, the default -is max(10, 2*NR_CPUS). Otherwise, the default is NR_CPUS. +set to a default value: max(10, 2*NR_CPUS). It's not a disaster if you set maxactive too low; you'll just miss some probes. In the kretprobe struct, the nmissed field is set to diff --git a/kernel/kprobes.c b/kernel/kprobes.c index a35074f0daa1..1c18ecf9f98b 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -2213,13 +2213,9 @@ int register_kretprobe(struct kretprobe *rp) rp->kp.post_handler = NULL; /* Pre-allocate memory for max kretprobe instances */ - if (rp->maxactive <= 0) { -#ifdef CONFIG_PREEMPTION + if (rp->maxactive <= 0) rp->maxactive = max_t(unsigned int, 10, 2*num_possible_cpus()); -#else - rp->maxactive = num_possible_cpus(); -#endif - } + #ifdef CONFIG_KRETPROBE_ON_RETHOOK rp->rh = rethook_alloc((void *)rp, kretprobe_rethook_handler); if (!rp->rh) |