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 9C1DEC433DB for ; Thu, 4 Feb 2021 19:19:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5116B64F38 for ; Thu, 4 Feb 2021 19:19:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239786AbhBDTS6 (ORCPT ); Thu, 4 Feb 2021 14:18:58 -0500 Received: from mail.kernel.org ([198.145.29.99]:52914 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239580AbhBDTSZ (ORCPT ); Thu, 4 Feb 2021 14:18:25 -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 594CE64F10; Thu, 4 Feb 2021 19:17:44 +0000 (UTC) Date: Thu, 4 Feb 2021 14:17:42 -0500 From: Steven Rostedt To: LKML Cc: Ingo Molnar , Andrew Morton , Peter Zijlstra , Mathieu Desnoyers Subject: [PATCH] tracepoints: Do not punish non static call users Message-ID: <20210204141742.46739ed2@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 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 double call only for architectures with static calls, and just call the iterator function directly for architectures without static calls. [ Tested only on architectures with static calls, will test on those without later ] Signed-off-by: Steven Rostedt (VMware) --- diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h index dc1d4c612cc3..966bfa6a861c 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 */ /* @@ -168,7 +177,6 @@ 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; \ \ @@ -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(); \