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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 932B9C43441 for ; Thu, 22 Nov 2018 01:29:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 650A52080F for ; Thu, 22 Nov 2018 01:29:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 650A52080F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391379AbeKVMFC (ORCPT ); Thu, 22 Nov 2018 07:05:02 -0500 Received: from mail.kernel.org ([198.145.29.99]:47796 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729623AbeKVMFC (ORCPT ); Thu, 22 Nov 2018 07:05:02 -0500 Received: from gandalf.local.home (cpe-66-24-56-78.stny.res.rr.com [66.24.56.78]) (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 0B8772075B; Thu, 22 Nov 2018 01:28:04 +0000 (UTC) Received: from rostedt by gandalf.local.home with local (Exim 4.91) (envelope-from ) id 1gPdmk-0005IV-WF; Wed, 21 Nov 2018 20:28:03 -0500 Message-Id: <20181122012802.894046175@goodmis.org> User-Agent: quilt/0.65 Date: Wed, 21 Nov 2018 20:27:10 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Andrew Morton , Thomas Gleixner , Peter Zijlstra , Masami Hiramatsu , Josh Poimboeuf , Frederic Weisbecker , Joel Fernandes , Andy Lutomirski , Mark Rutland , Namhyung Kim Subject: [RFC][PATCH 02/14] fgraph: Have set_graph_notrace only affect function_graph tracer References: <20181122012708.491151844@goodmis.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Steven Rostedt (VMware)" In order to make the function graph infrastructure more generic, there can not be code specific for the function_graph tracer in the generic code. This includes the set_graph_notrace logic, that stops all graph calls when a function in the set_graph_notrace is hit. By using the trace_recursion mask, we can use a bit in the current task_struct to implement the notrace code, and move the logic out of fgraph.c and into trace_functions_graph.c and keeps it affecting only the tracer and not all call graph callbacks. Cc: Namhyung Kim Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/fgraph.c | 21 --------------------- kernel/trace/trace.h | 6 ++++++ kernel/trace/trace_functions_graph.c | 21 +++++++++++++++++++++ 3 files changed, 27 insertions(+), 21 deletions(-) diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c index e8fcf1b2b38c..c684968b87e7 100644 --- a/kernel/trace/fgraph.c +++ b/kernel/trace/fgraph.c @@ -64,30 +64,9 @@ ftrace_push_return_trace(unsigned long ret, unsigned long func, return -EBUSY; } - /* - * The curr_ret_stack is an index to ftrace return stack of - * current task. Its value should be in [0, FTRACE_RETFUNC_ - * DEPTH) when the function graph tracer is used. To support - * filtering out specific functions, it makes the index - * negative by subtracting huge value (FTRACE_NOTRACE_DEPTH) - * so when it sees a negative index the ftrace will ignore - * the record. And the index gets recovered when returning - * from the filtered function by adding the FTRACE_NOTRACE_ - * DEPTH and then it'll continue to record functions normally. - * - * The curr_ret_stack is initialized to -1 and get increased - * in this function. So it can be less than -1 only if it was - * filtered out via ftrace_graph_notrace_addr() which can be - * set from set_graph_notrace file in tracefs by user. - */ - if (current->curr_ret_stack < -1) - return -EBUSY; - calltime = trace_clock_local(); index = ++current->curr_ret_stack; - if (ftrace_graph_notrace_addr(func)) - current->curr_ret_stack -= FTRACE_NOTRACE_DEPTH; barrier(); current->ret_stack[index].ret = ret; current->ret_stack[index].func = func; diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 3b8c0e24ab30..f3ad85830961 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -512,6 +512,12 @@ enum { * can only be modified by current, we can reuse trace_recursion. */ TRACE_IRQ_BIT, +/* + * To implement set_graph_notrace, if this bit is set, we ignore + * function graph tracing of called functions, until the return + * function is called to clear it. + */ + TRACE_GRAPH_NOTRACE_BIT, }; #define trace_recursion_set(bit) do { (current)->trace_recursion |= (1<<(bit)); } while (0) diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c index af1759cd6eab..4748dc1bf5e1 100644 --- a/kernel/trace/trace_functions_graph.c +++ b/kernel/trace/trace_functions_graph.c @@ -188,6 +188,18 @@ int trace_graph_entry(struct ftrace_graph_ent *trace) int cpu; int pc; + if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT)) + return 0; + + if (ftrace_graph_notrace_addr(trace->func)) { + trace_recursion_set(TRACE_GRAPH_NOTRACE_BIT); + /* + * Need to return 1 to have the return called + * that will clear the NOTRACE bit. + */ + return 1; + } + if (!ftrace_trace_task(tr)) return 0; @@ -288,6 +300,11 @@ void trace_graph_return(struct ftrace_graph_ret *trace) int cpu; int pc; + if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT)) { + trace_recursion_clear(TRACE_GRAPH_NOTRACE_BIT); + return; + } + local_irq_save(flags); cpu = raw_smp_processor_id(); data = per_cpu_ptr(tr->trace_buffer.data, cpu); @@ -311,6 +328,10 @@ void set_graph_array(struct trace_array *tr) static void trace_graph_thresh_return(struct ftrace_graph_ret *trace) { + if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT)) { + trace_recursion_clear(TRACE_GRAPH_NOTRACE_BIT); + return; + } if (tracing_thresh && (trace->rettime - trace->calltime < tracing_thresh)) return; -- 2.19.1