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=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 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 62A04C43603 for ; Sat, 6 Feb 2021 03:22:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 334D564FDC for ; Sat, 6 Feb 2021 03:22:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232501AbhBFDVu (ORCPT ); Fri, 5 Feb 2021 22:21:50 -0500 Received: from mail.kernel.org ([198.145.29.99]:38112 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231145AbhBFClz (ORCPT ); Fri, 5 Feb 2021 21:41:55 -0500 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (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 A9D4D64F91; Fri, 5 Feb 2021 21:55:04 +0000 (UTC) Date: Fri, 5 Feb 2021 16:55:03 -0500 From: Steven Rostedt To: LKML Cc: Ingo Molnar , Andrew Morton , Peter Zijlstra , Mathieu Desnoyers Subject: [PATCH v2] tracepoints: Do not punish non static call users Message-ID: <20210205165503.70baa91a@gandalf.local.home> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Steven Rostedt With static calls, a tracepoint can call the callback directly if there is only one callback registered to that tracepoint. When there is more than one, the static call will call the tracepoint's "iterator" function, which needs to reload the tracepoint's "funcs" array again, as it could have changed since the first time it was loaded. But an arch without static calls is punished by having to load the tracepoint's "funcs" array twice. Once in the DO_TRACE macro, and once again in the iterator macro. For archs without static calls, there's no reason to load the array macro in the first place, since the iterator function will do it anyway. Change the __DO_TRACE_CALL() macro to do the load and call of the tracepoints funcs array only for architectures with static calls, and just call the iterator function directly for architectures without static calls. Signed-off-by: Steven Rostedt (VMware) --- Changes since v1: - Updated change log (no double calls) - Added "__maybe_unused" to void *__data include/linux/tracepoint.h | 23 +++++++++++++---------- 1 file changed, 13 insertions(+), 10 deletions(-) diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h index 966ed8980327..db2c8484b4b1 100644 --- a/include/linux/tracepoint.h +++ b/include/linux/tracepoint.h @@ -152,9 +152,18 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) #ifdef TRACEPOINTS_ENABLED #ifdef CONFIG_HAVE_STATIC_CALL -#define __DO_TRACE_CALL(name) static_call(tp_func_##name) +#define __DO_TRACE_CALL(name, args) \ + do { \ + struct tracepoint_func *it_func_ptr; \ + it_func_ptr = \ + rcu_dereference_raw((&__tracepoint_##name)->funcs); \ + if (it_func_ptr) { \ + __data = (it_func_ptr)->data; \ + static_call(tp_func_##name)(args); \ + } \ + } while (0) #else -#define __DO_TRACE_CALL(name) __traceiter_##name +#define __DO_TRACE_CALL(name, args) __traceiter_##name(args) #endif /* CONFIG_HAVE_STATIC_CALL */ /* @@ -168,9 +177,8 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) */ #define __DO_TRACE(name, proto, args, cond, rcuidle) \ do { \ - struct tracepoint_func *it_func_ptr; \ int __maybe_unused __idx = 0; \ - void *__data; \ + void __maybe_unused *__data; \ \ if (!(cond)) \ return; \ @@ -190,12 +198,7 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) rcu_irq_enter_irqson(); \ } \ \ - it_func_ptr = \ - rcu_dereference_raw((&__tracepoint_##name)->funcs); \ - if (it_func_ptr) { \ - __data = (it_func_ptr)->data; \ - __DO_TRACE_CALL(name)(args); \ - } \ + __DO_TRACE_CALL(name, TP_ARGS(args)); \ \ if (rcuidle) { \ rcu_irq_exit_irqson(); \ -- 2.25.4