From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3DCEBC10F26 for ; Mon, 23 Mar 2020 06:47:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0BF682074D for ; Mon, 23 Mar 2020 06:47:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584946067; bh=cla2juA7Pkm2R77Y1ajC8PVPD42viMocN+1qYemefqY=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=dC3RXp86Yxjggzf01rE7Bt/ScPIFyPTu5XsnH514m0cFFrMF9D5EiIlpzFTRF9bzj HQ7RyxXgqPnFKl48NegCSwHGObP+Mtxag55kUXCjMkVM4mPi1jylPNMjLrU9LtRq97 N9I+9DSkkt6eBDxyHSBuzT0fS8iRVxqKQXau2Z34= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727164AbgCWGrq (ORCPT ); Mon, 23 Mar 2020 02:47:46 -0400 Received: from mail.kernel.org ([198.145.29.99]:48938 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726142AbgCWGrq (ORCPT ); Mon, 23 Mar 2020 02:47:46 -0400 Received: from devnote2 (NE2965lan1.rev.em-net.ne.jp [210.141.244.193]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B05E620736; Mon, 23 Mar 2020 06:47:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584946066; bh=cla2juA7Pkm2R77Y1ajC8PVPD42viMocN+1qYemefqY=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=aE7tJ26aVqz0Y3EzPOYMNtb/LjUu+xPF2S5m6o4qKlQ/uz+fnSxv3FPGBq9OGLNPt vY20PXIedKBptWV7kd7ooPlyQ0f1DUzKe5C+u/moes9n2aDH4uwiJ71oQR4zv9HFme 89JQKLRfPZrZE7+BnQafjXsSXNKZLS/zKZO8qxfU= Date: Mon, 23 Mar 2020 15:47:41 +0900 From: Masami Hiramatsu To: Taeung Song Cc: linux-trace-users@vger.kernel.org, Masami Hiramatsu , "David S. Miller" Subject: Re: How to recheck 'maxactive' ? Message-Id: <20200323154741.0643126b3684c950bb37bf7e@kernel.org> In-Reply-To: <4762764a-6df7-bc93-ed60-e336146dce1f@gmail.com> References: <4762764a-6df7-bc93-ed60-e336146dce1f@gmail.com> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.32; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-trace-users-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-trace-users@vger.kernel.org Hi Taeung, On Sun, 22 Mar 2020 23:06:20 +0900 Taeung Song wrote: > Hi, > > After setting 'maxactive' for kretprobe, > how can I recheck the value of 'maxactive' ? > For example, in order to distinguish the difference > between two kretprobe events > (kmem_cache_alloc_node and kmem_cache_alloc_node10) > > $ cd /sys/kernel/debug/tracing > $ echo 'r:kmem_cache_alloc_node kmem_cache_alloc_node' >> kprobe_events > $ echo 'r10:kmem_cache_alloc_node10 kmem_cache_alloc_node' >> > kprobe_events > > $ cat kprobe_events > r:kprobes/kmem_cache_alloc_node kmem_cache_alloc_node > r:kprobes/kmem_cache_alloc_node10 kmem_cache_alloc_node Oops! good catch. That must be a bug, since the kprobe_events design policy is to support following operation. $ cat kprobe_events > /etc/event_setting (reboot) $ cat /etc/event_setting > kprobe_events What about below patch? >From 935ed56819f2bfb7ac977f5c63273c9a6e3dfb42 Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Mon, 23 Mar 2020 10:57:48 +0900 Subject: [PATCH] ftrace/kprobe: Show the maxactive number on kprobe_events Show maxactive parameter on kprobe_events. This allows user to save the current configuration and restore it without losing maxactive parameter. Signed-off-by: Masami Hiramatsu --- kernel/trace/trace_kprobe.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index 362cca52f5de..d0568af4a0ef 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -1078,6 +1078,8 @@ static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev) int i; seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p'); + if (trace_kprobe_is_return(tk) && tk->rp.maxactive) + seq_printf(m, "%d", tk->rp.maxactive); seq_printf(m, ":%s/%s", trace_probe_group_name(&tk->tp), trace_probe_name(&tk->tp)); -- 2.20.1 Thank you, -- Masami Hiramatsu