From nobody Sun Feb 8 15:29:01 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D07A6C001DF for ; Mon, 31 Jul 2023 23:17:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231152AbjGaXRl (ORCPT ); Mon, 31 Jul 2023 19:17:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40198 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231907AbjGaXRX (ORCPT ); Mon, 31 Jul 2023 19:17:23 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 921F61FDE for ; Mon, 31 Jul 2023 16:17:15 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id BBE6F61361 for ; Mon, 31 Jul 2023 23:17:07 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2E281C433C8; Mon, 31 Jul 2023 23:17:07 +0000 (UTC) Received: from rostedt by gandalf with local (Exim 4.96) (envelope-from ) id 1qQc8Q-003fMV-0D; Mon, 31 Jul 2023 19:17:06 -0400 Message-ID: <20230731231705.888984593@goodmis.org> User-Agent: quilt/0.66 Date: Mon, 31 Jul 2023 19:16:39 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Masami Hiramatsu , Mark Rutland , Andrew Morton , Zheng Yejian Subject: [for-next][PATCH 05/15] tracing: Set actual size after ring buffer resize References: <20230731231634.031452225@goodmis.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Zheng Yejian Currently we can resize trace ringbuffer by writing a value into file 'buffer_size_kb', then by reading the file, we get the value that is usually what we wrote. However, this value may be not actual size of trace ring buffer because of the round up when doing resize in kernel, and the actual size would be more useful. Link: https://lore.kernel.org/linux-trace-kernel/20230705002705.576633-1-zh= engyejian1@huawei.com Cc: Signed-off-by: Zheng Yejian Signed-off-by: Steven Rostedt (Google) --- kernel/trace/trace.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index a3c4f9826872..bc96567dc230 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -6286,6 +6286,15 @@ static void set_buffer_entries(struct array_buffer *= buf, unsigned long val) per_cpu_ptr(buf->data, cpu)->entries =3D val; } =20 +static void update_buffer_entries(struct array_buffer *buf, int cpu) +{ + if (cpu =3D=3D RING_BUFFER_ALL_CPUS) { + set_buffer_entries(buf, ring_buffer_size(buf->buffer, 0)); + } else { + per_cpu_ptr(buf->data, cpu)->entries =3D ring_buffer_size(buf->buffer, c= pu); + } +} + #ifdef CONFIG_TRACER_MAX_TRACE /* resize @tr's buffer to the size of @size_tr's entries */ static int resize_buffer_duplicate_size(struct array_buffer *trace_buf, @@ -6364,18 +6373,12 @@ static int __tracing_resize_ring_buffer(struct trac= e_array *tr, return ret; } =20 - if (cpu =3D=3D RING_BUFFER_ALL_CPUS) - set_buffer_entries(&tr->max_buffer, size); - else - per_cpu_ptr(tr->max_buffer.data, cpu)->entries =3D size; + update_buffer_entries(&tr->max_buffer, cpu); =20 out: #endif /* CONFIG_TRACER_MAX_TRACE */ =20 - if (cpu =3D=3D RING_BUFFER_ALL_CPUS) - set_buffer_entries(&tr->array_buffer, size); - else - per_cpu_ptr(tr->array_buffer.data, cpu)->entries =3D size; + update_buffer_entries(&tr->array_buffer, cpu); =20 return ret; } --=20 2.40.1