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=-13.8 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 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 4794AC433DB for ; Wed, 3 Feb 2021 16:09:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E6F9C64E36 for ; Wed, 3 Feb 2021 16:09:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234860AbhBCQJB (ORCPT ); Wed, 3 Feb 2021 11:09:01 -0500 Received: from mail.kernel.org ([198.145.29.99]:36046 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234922AbhBCQHa (ORCPT ); Wed, 3 Feb 2021 11:07:30 -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 09FB564F93; Wed, 3 Feb 2021 16:05:51 +0000 (UTC) Received: from rostedt by gandalf.local.home with local (Exim 4.94) (envelope-from ) id 1l7Kf7-009J91-UX; Wed, 03 Feb 2021 11:05:49 -0500 Message-ID: <20210203160549.825691017@goodmis.org> User-Agent: quilt/0.66 Date: Wed, 03 Feb 2021 11:05:25 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Andrew Morton , Sebastian Andrzej Siewior Subject: [for-next][PATCH 08/15] tracing: Use in_serving_softirq() to deduct softirq status. References: <20210203160517.982448432@goodmis.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Sebastian Andrzej Siewior PREEMPT_RT does not report "serving softirq" because the tracing core looks at the preemption counter while PREEMPT_RT does not update it while processing softirqs in order to remain preemptible. The information is stored somewhere else. The in_serving_softirq() macro and the SOFTIRQ_OFFSET define are still working but not on the preempt-counter. Use in_serving_softirq() macro which works on PREEMPT_RT. On !PREEMPT_RT the compiler (gcc-10 / clang-11) is smart enough to optimize the in_serving_softirq() related read of the preemption counter away. The only difference I noticed by using in_serving_softirq() on !PREEMPT_RT is that gcc-10 implemented tracing_gen_ctx_flags() as reading FLAG, jmp _tracing_gen_ctx_flags(). Without in_serving_softirq() it inlined _tracing_gen_ctx_flags() into tracing_gen_ctx_flags(). Link: https://lkml.kernel.org/r/20210125194511.3924915-4-bigeasy@linutronix.de Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 584fa2a1304a..75620c29e904 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -2590,8 +2590,7 @@ unsigned int tracing_gen_ctx_irq_test(unsigned int irqs_status) trace_flags |= TRACE_FLAG_NMI; if (pc & HARDIRQ_MASK) trace_flags |= TRACE_FLAG_HARDIRQ; - - if (pc & SOFTIRQ_OFFSET) + if (in_serving_softirq()) trace_flags |= TRACE_FLAG_SOFTIRQ; if (tif_need_resched()) -- 2.29.2