On Tue, 4 Apr 2017 20:24:59 +0900 Masami Hiramatsu <mhiramat@xxxxxxxxxx> wrote: > On Mon, 3 Apr 2017 12:36:22 +0200 > Alban Crequy <alban.crequy@xxxxxxxxx> wrote: > > > From: Alban Crequy <alban@xxxxxxxxxx> > > > > When a kretprobe is installed on a kernel function, there is a maximum > > limit of how many calls in parallel it can catch (aka "maxactive"). A > > kernel module could call register_kretprobe() and initialize maxactive > > (see example in samples/kprobes/kretprobe_example.c). > > > > But that is not exposed to userspace and it is currently not possible to > > choose maxactive when writing to /sys/kernel/debug/tracing/kprobe_events > > > > The default maxactive can be as low as 1 on single-core with a > > non-preemptive kernel. This is too low and we need to increase it not > > only for recursive functions, but for functions that sleep or resched. > > > > This patch updates the format of the command that can be written to > > kprobe_events so that maxactive can be optionally specified. > > > > I need this for a bpf program attached to the kretprobe of > > inet_csk_accept, which can sleep for a long time. > > > > This patch includes a basic selftest: > > > > > # ./ftracetest -v test.d/kprobe/ > > > === Ftrace unit tests === > > > [1] Kprobe dynamic event - adding and removing [PASS] > > > [2] Kprobe dynamic event - busy event check [PASS] > > > [3] Kprobe dynamic event with arguments [PASS] > > > [4] Kprobes event arguments with types [PASS] > > > [5] Kprobe dynamic event with function tracer [PASS] > > > [6] Kretprobe dynamic event with arguments [PASS] > > > [7] Kretprobe dynamic event with maxactive [PASS] > > > > > > # of passed: 7 > > > # of failed: 0 > > > # of unresolved: 0 > > > # of untested: 0 > > > # of unsupported: 0 > > > # of xfailed: 0 > > > # of undefined(test bug): 0 > > > > BugLink: https://github.com/iovisor/bcc/issues/1072 > > Signed-off-by: Alban Crequy <alban@xxxxxxxxxx> > > Looks good to me. > > Acked-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx> > Applied, thanks! -- Steve -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
