From patchwork Tue Dec 19 18:54:17 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Rostedt X-Patchwork-Id: 181216 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a05:7300:24d3:b0:fb:cd0c:d3e with SMTP id r19csp2155699dyi; Tue, 19 Dec 2023 10:57:09 -0800 (PST) X-Google-Smtp-Source: AGHT+IH/UQhqDS6zIQ4Qis3kNDeswqeK0IRZp+UFTTQZiROru7dKj53IrmeeyC6gOw4BLiBeZYux X-Received: by 2002:a17:902:e847:b0:1d3:b816:6100 with SMTP id t7-20020a170902e84700b001d3b8166100mr2811219plg.24.1703012228890; Tue, 19 Dec 2023 10:57:08 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1703012228; cv=none; d=google.com; s=arc-20160816; b=Uvbyz/MorI6HgTstERs8BTDgSx4mel6MNOHIcvINEeLTx0Gl2vSzyxmYyZCNZo1zry 5lKy6vcoYdbLl+20/TmjqlhPKmFVnTM8JZw9F3poEzV8Vc06IUlUViq1ijL2r4ZWEQ5X Yt7nV/h/ixDPGGnqNUVVbh/JhXyDQg+Uv/nUDgyxriLWeAds8ZXHpefDlrqCnqevpq6j BGXguP4eNGyy/ICux0Qo73rapJUYQZ29OzWJur1JMsHQ9hqdPivnnqT8ZV4BQWF69Az1 tvZSjJ2MHzgUEimSAswgWOe/Uw8cAQNw9H4b2Sc0NAhILazYqgySz6bB37XJY3dWh8RF h+hQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:list-unsubscribe:list-subscribe:list-id:precedence :references:subject:cc:to:from:date:user-agent:message-id; bh=nyWZcSkMBA1EJSi9kwPdm/RbGS9v7JOi2RKJ3+2p3o0=; fh=pL1t9p0RxD5qCgSUniSa3P4+XmpksJYPzX6TE+dndao=; b=TOrJ0SGGihaGMpyNXhXv3/dGfXEQcDL3MsbyYoMi9VT/gdG8T4xWOGZlHJJ1bsVIhR Et5S84qTW+USs9klayNPybDXbi6Ta2F5m9qBWrm2X1d0on0azqwpg7wFRcz92vK1fWdR n99Gt/rLmrv1aYGBNCnxJc3d6T31F3UdumA2tpx9BvAqnlXqBfyl+XsOB21xAHTcRr4u lp6kyMwm5O+GrsPoErWg71N3a1KvaoPyyFb4HKScD31GY4TvGkl79rTavNGDv1W/gEOo uXpJdjLRaFHS8F4XlRDRGK+a7Cedw35Num2SSmquZUv0DiKeh8WERPnMm2vnIYJBInPS sVyA== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel+bounces-5837-ouuuleilei=gmail.com@vger.kernel.org designates 139.178.88.99 as permitted sender) smtp.mailfrom="linux-kernel+bounces-5837-ouuuleilei=gmail.com@vger.kernel.org" Received: from sv.mirrors.kernel.org (sv.mirrors.kernel.org. [139.178.88.99]) by mx.google.com with ESMTPS id b6-20020a170902bd4600b001d00c80f3b3si19659679plx.280.2023.12.19.10.57.08 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 19 Dec 2023 10:57:08 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel+bounces-5837-ouuuleilei=gmail.com@vger.kernel.org designates 139.178.88.99 as permitted sender) client-ip=139.178.88.99; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel+bounces-5837-ouuuleilei=gmail.com@vger.kernel.org designates 139.178.88.99 as permitted sender) smtp.mailfrom="linux-kernel+bounces-5837-ouuuleilei=gmail.com@vger.kernel.org" Received: from smtp.subspace.kernel.org (wormhole.subspace.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sv.mirrors.kernel.org (Postfix) with ESMTPS id 3E13C2879E1 for ; Tue, 19 Dec 2023 18:57:08 +0000 (UTC) Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 15D693D0BD; Tue, 19 Dec 2023 18:55:32 +0000 (UTC) X-Original-To: linux-kernel@vger.kernel.org Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 606F938FB8; Tue, 19 Dec 2023 18:55:29 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 11C5AC433CD; Tue, 19 Dec 2023 18:55:29 +0000 (UTC) Received: from rostedt by gandalf with local (Exim 4.97) (envelope-from ) id 1rFfGW-00000003R0r-2BgT; Tue, 19 Dec 2023 13:56:28 -0500 Message-ID: <20231219185628.298324722@goodmis.org> User-Agent: quilt/0.67 Date: Tue, 19 Dec 2023 13:54:17 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Cc: Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers , Andrew Morton , Tzvetomir Stoyanov , Vincent Donnefort , Kent Overstreet Subject: [PATCH v5 03/15] ring-buffer: Add interface for configuring trace sub buffer size References: <20231219185414.474197117@goodmis.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1785737750805018283 X-GMAIL-MSGID: 1785737750805018283 From: "Tzvetomir Stoyanov (VMware)" The trace ring buffer sub page size can be configured, per trace instance. A new ftrace file "buffer_subbuf_order" is added to get and set the size of the ring buffer sub page for current trace instance. The size must be an order of system page size, that's why the new interface works with system page order, instead of absolute page size: 0 means the ring buffer sub page is equal to 1 system page and so forth: 0 - 1 system page 1 - 2 system pages 2 - 4 system pages ... The ring buffer sub page size is limited between 1 and 128 system pages. The default value is 1 system page. New ring buffer APIs are introduced: ring_buffer_subbuf_order_set() ring_buffer_subbuf_order_get() ring_buffer_subbuf_size_get() Link: https://lore.kernel.org/linux-trace-devel/20211213094825.61876-4-tz.stoyanov@gmail.com Signed-off-by: Tzvetomir Stoyanov (VMware) Signed-off-by: Steven Rostedt (Google) --- include/linux/ring_buffer.h | 4 ++ kernel/trace/ring_buffer.c | 73 +++++++++++++++++++++++++++++++++++++ kernel/trace/trace.c | 48 ++++++++++++++++++++++++ 3 files changed, 125 insertions(+) diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h index ce46218ce46d..12573306b889 100644 --- a/include/linux/ring_buffer.h +++ b/include/linux/ring_buffer.h @@ -202,6 +202,10 @@ struct trace_seq; int ring_buffer_print_entry_header(struct trace_seq *s); int ring_buffer_print_page_header(struct trace_buffer *buffer, struct trace_seq *s); +int ring_buffer_subbuf_order_get(struct trace_buffer *buffer); +int ring_buffer_subbuf_order_set(struct trace_buffer *buffer, int order); +int ring_buffer_subbuf_size_get(struct trace_buffer *buffer); + enum ring_buffer_flags { RB_FL_OVERWRITE = 1 << 0, }; diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index d9f656502400..20fc0121735d 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -507,6 +507,7 @@ struct trace_buffer { bool time_stamp_abs; unsigned int subbuf_size; + unsigned int subbuf_order; unsigned int max_data_size; }; @@ -5761,6 +5762,78 @@ int ring_buffer_read_page(struct trace_buffer *buffer, } EXPORT_SYMBOL_GPL(ring_buffer_read_page); +/** + * ring_buffer_subbuf_size_get - get size of the sub buffer. + * @buffer: the buffer to get the sub buffer size from + * + * Returns size of the sub buffer, in bytes. + */ +int ring_buffer_subbuf_size_get(struct trace_buffer *buffer) +{ + return buffer->subbuf_size + BUF_PAGE_HDR_SIZE; +} +EXPORT_SYMBOL_GPL(ring_buffer_subbuf_size_get); + +/** + * ring_buffer_subbuf_order_get - get order of system sub pages in one buffer page. + * @buffer: The ring_buffer to get the system sub page order from + * + * By default, one ring buffer sub page equals to one system page. This parameter + * is configurable, per ring buffer. The size of the ring buffer sub page can be + * extended, but must be an order of system page size. + * + * Returns the order of buffer sub page size, in system pages: + * 0 means the sub buffer size is 1 system page and so forth. + * In case of an error < 0 is returned. + */ +int ring_buffer_subbuf_order_get(struct trace_buffer *buffer) +{ + if (!buffer) + return -EINVAL; + + return buffer->subbuf_order; +} +EXPORT_SYMBOL_GPL(ring_buffer_subbuf_order_get); + +/** + * ring_buffer_subbuf_order_set - set the size of ring buffer sub page. + * @buffer: The ring_buffer to set the new page size. + * @order: Order of the system pages in one sub buffer page + * + * By default, one ring buffer pages equals to one system page. This API can be + * used to set new size of the ring buffer page. The size must be order of + * system page size, that's why the input parameter @order is the order of + * system pages that are allocated for one ring buffer page: + * 0 - 1 system page + * 1 - 2 system pages + * 3 - 4 system pages + * ... + * + * Returns 0 on success or < 0 in case of an error. + */ +int ring_buffer_subbuf_order_set(struct trace_buffer *buffer, int order) +{ + int psize; + + if (!buffer || order < 0) + return -EINVAL; + + if (buffer->subbuf_order == order) + return 0; + + psize = (1 << order) * PAGE_SIZE; + if (psize <= BUF_PAGE_HDR_SIZE) + return -EINVAL; + + buffer->subbuf_order = order; + buffer->subbuf_size = psize - BUF_PAGE_HDR_SIZE; + + /* Todo: reset the buffer with the new page size */ + + return 0; +} +EXPORT_SYMBOL_GPL(ring_buffer_subbuf_order_set); + /* * We only allocate new buffers, never free them if the CPU goes down. * If we were to free the buffer, then the user would lose any trace that was in diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 76dd0a4c8cb5..a010aba4c4a4 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -9358,6 +9358,51 @@ static const struct file_operations buffer_percent_fops = { .llseek = default_llseek, }; +static ssize_t +buffer_order_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) +{ + struct trace_array *tr = filp->private_data; + char buf[64]; + int r; + + r = sprintf(buf, "%d\n", ring_buffer_subbuf_order_get(tr->array_buffer.buffer)); + + return simple_read_from_buffer(ubuf, cnt, ppos, buf, r); +} + +static ssize_t +buffer_order_write(struct file *filp, const char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + struct trace_array *tr = filp->private_data; + unsigned long val; + int ret; + + ret = kstrtoul_from_user(ubuf, cnt, 10, &val); + if (ret) + return ret; + + /* limit between 1 and 128 system pages */ + if (val < 0 || val > 7) + return -EINVAL; + + ret = ring_buffer_subbuf_order_set(tr->array_buffer.buffer, val); + if (ret) + return ret; + + (*ppos)++; + + return cnt; +} + +static const struct file_operations buffer_order_fops = { + .open = tracing_open_generic_tr, + .read = buffer_order_read, + .write = buffer_order_write, + .release = tracing_release_generic_tr, + .llseek = default_llseek, +}; + static struct dentry *trace_instance_dir; static void @@ -9824,6 +9869,9 @@ init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer) trace_create_file("buffer_percent", TRACE_MODE_WRITE, d_tracer, tr, &buffer_percent_fops); + trace_create_file("buffer_subbuf_order", TRACE_MODE_WRITE, d_tracer, + tr, &buffer_order_fops); + create_trace_options_dir(tr); #ifdef CONFIG_TRACER_MAX_TRACE