From patchwork Sun Aug 18 13:18:34 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Masami Hiramatsu (Google)" X-Patchwork-Id: 13767447 X-Patchwork-Delegate: mhiramat@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 417BE45007; Sun, 18 Aug 2024 13:18:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723987118; cv=none; b=AzAMQ3Fy2BW7NFntP5LCWqv4IQdiSpJIeURxXhn+muodsmorDk9WDZkSbKkG1aRPPDpuX1VlQkFerNRdlFPg5PjjjOEpphf6F8GTrLjK3+tRO+lI4zqs6GPAmxLkIcyUD6cRMXprar8AYK+48mlG06FCcu0aMYhuRqlQvp3xaaM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723987118; c=relaxed/simple; bh=PduHRgfMp3qDtlIlUMaJZfdj3y/ud8IXpCM0H4jkdiM=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=gcsPgCGT8OGyXIYNQO2p0zkpAbzCC9DV+MNIMxWiiI6Hu6CbrA/Vpd/sTashtpXQGwd9U2SJliuneeEYVwbdGd8aIyLntvjPgaJGw/LJ/7C0m0sezJqCBxc11FiIEQbvpYqy4us+TY9/AlVmGkRuHFNSljeNpJobENBOOVmXWpc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=in8QWJjZ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="in8QWJjZ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3AD90C32786; Sun, 18 Aug 2024 13:18:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1723987118; bh=PduHRgfMp3qDtlIlUMaJZfdj3y/ud8IXpCM0H4jkdiM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=in8QWJjZdwDFuKZw/wPgrjV2DY2b7x/gYZVuiD2cAybbhGGaIn91b0q0FcZXPB6+X Ox1wcovtCisp0pT1ESXStWggr3JSXt6JVQ5ZHQCrV1y/Al9Dzq7s27ebZ4a0WlxUVc uUJNN+akhLRzVBf8sM34CUbUKho9wuSsaCopHKy5WO7bxapz24+W8cFhLRM+XsZFqB faW3rhk5zZdUbxaUFopBrbTnLiuj/1vax0eoxn95D+tTo/CXO/EE7ysBjpD0GDK64c hFFT773he+9HAF6LOZa5XZuzjXQ2CvuKkHcIZZk5/4eEJjGYaQWSEa/t2zgKX5CQ72 kof8HTYBSvlDA== From: "Masami Hiramatsu (Google)" To: Steven Rostedt , Shuah Khan Cc: Masami Hiramatsu , Tom Zanussi , Mathieu Desnoyers , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: [PATCH v5 1/3] tracing/hist: Add poll(POLLIN) support on hist file Date: Sun, 18 Aug 2024 22:18:34 +0900 Message-Id: <172398711398.295714.5203663482865135771.stgit@devnote2> X-Mailer: git-send-email 2.34.1 In-Reply-To: <172398710447.295714.4489282566285719918.stgit@devnote2> References: <172398710447.295714.4489282566285719918.stgit@devnote2> User-Agent: StGit/0.19 Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Masami Hiramatsu (Google) Add poll syscall support on the `hist` file. The Waiter will be waken up when the histogram is updated with POLLIN. Currently, there is no way to wait for a specific event in userspace. So user needs to peek the `trace` periodicaly, or wait on `trace_pipe`. But that is not good idea to peek the `trace` for the event randomely happens. And `trace_pipe` is not coming back until a page is filled with events. This allows user to wait for a specific events on `hist` file. User can set a histogram trigger on the event which they want to monitor. And poll() on its `hist` file. Since this poll() returns POLLIN, the next poll() will return soon unless you do read() on hist file. NOTE: To read the hist file again, you must set the file offset to 0, but just for monitoring the event, you may not need to read the histogram. Signed-off-by: Masami Hiramatsu (Google) Reviewed-by: Tom Zanussi --- include/linux/trace_events.h | 5 +++ kernel/trace/trace_events.c | 18 +++++++++ kernel/trace/trace_events_hist.c | 76 +++++++++++++++++++++++++++++++++++++- 3 files changed, 96 insertions(+), 3 deletions(-) diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h index 42bedcddd511..f3ec67d34097 100644 --- a/include/linux/trace_events.h +++ b/include/linux/trace_events.h @@ -663,6 +663,11 @@ struct trace_event_file { struct trace_subsystem_dir *system; struct list_head triggers; +#ifdef CONFIG_HIST_TRIGGERS + struct irq_work hist_work; + wait_queue_head_t hist_wq; +#endif + /* * 32 bit flags: * bit 0: enabled diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 7266ec2a4eea..0f077b32eea4 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -2972,6 +2972,20 @@ static bool event_in_systems(struct trace_event_call *call, return !*p || isspace(*p) || *p == ','; } +#ifdef CONFIG_HIST_TRIGGERS +/* + * Wake up waiter on the hist_wq from irq_work because the hist trigger + * may happen in any context. + */ +static void hist_event_irq_work(struct irq_work *work) +{ + struct trace_event_file *event_file; + + event_file = container_of(work, struct trace_event_file, hist_work); + wake_up_all(&event_file->hist_wq); +} +#endif + static struct trace_event_file * trace_create_new_event(struct trace_event_call *call, struct trace_array *tr) @@ -3004,6 +3018,10 @@ trace_create_new_event(struct trace_event_call *call, INIT_LIST_HEAD(&file->triggers); list_add(&file->list, &tr->events); refcount_set(&file->ref, 1); +#ifdef CONFIG_HIST_TRIGGERS + init_irq_work(&file->hist_work, hist_event_irq_work); + init_waitqueue_head(&file->hist_wq); +#endif return file; } diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index 5f9119eb7c67..d27b60f54f68 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -5314,6 +5314,9 @@ static void event_hist_trigger(struct event_trigger_data *data, if (resolve_var_refs(hist_data, key, var_ref_vals, true)) hist_trigger_actions(hist_data, elt, buffer, rec, rbe, key, var_ref_vals); + + if (hist_data->event_file && wq_has_sleeper(&hist_data->event_file->hist_wq)) + irq_work_queue(&hist_data->event_file->hist_work); } static void hist_trigger_stacktrace_print(struct seq_file *m, @@ -5593,15 +5596,36 @@ static void hist_trigger_show(struct seq_file *m, n_entries, (u64)atomic64_read(&hist_data->map->drops)); } +struct hist_file_data { + struct file *file; + u64 last_read; +}; + +static u64 get_hist_hit_count(struct trace_event_file *event_file) +{ + struct hist_trigger_data *hist_data; + struct event_trigger_data *data; + u64 ret = 0; + + list_for_each_entry(data, &event_file->triggers, list) { + if (data->cmd_ops->trigger_type == ETT_EVENT_HIST) { + hist_data = data->private_data; + ret += atomic64_read(&hist_data->map->hits); + } + } + return ret; +} + static int hist_show(struct seq_file *m, void *v) { + struct hist_file_data *hist_file = m->private; struct event_trigger_data *data; struct trace_event_file *event_file; int n = 0, ret = 0; mutex_lock(&event_mutex); - event_file = event_file_file(m->private); + event_file = event_file_file(hist_file->file); if (unlikely(!event_file)) { ret = -ENODEV; goto out_unlock; @@ -5611,6 +5635,7 @@ static int hist_show(struct seq_file *m, void *v) if (data->cmd_ops->trigger_type == ETT_EVENT_HIST) hist_trigger_show(m, data, n++); } + hist_file->last_read = get_hist_hit_count(event_file); out_unlock: mutex_unlock(&event_mutex); @@ -5618,24 +5643,69 @@ static int hist_show(struct seq_file *m, void *v) return ret; } +static __poll_t event_hist_poll(struct file *file, struct poll_table_struct *wait) +{ + struct trace_event_file *event_file; + struct seq_file *m = file->private_data; + struct hist_file_data *hist_file = m->private; + __poll_t ret = 0; + + mutex_lock(&event_mutex); + + event_file = event_file_data(file); + if (!event_file) { + ret = EPOLLERR; + goto out_unlock; + } + + poll_wait(file, &event_file->hist_wq, wait); + + if (hist_file->last_read != get_hist_hit_count(event_file)) + ret = EPOLLIN | EPOLLRDNORM; + +out_unlock: + mutex_unlock(&event_mutex); + + return ret; +} + +static int event_hist_release(struct inode *inode, struct file *file) +{ + struct seq_file *m = file->private_data; + struct hist_file_data *hist_file = m->private; + + kfree(hist_file); + return tracing_single_release_file_tr(inode, file); +} + static int event_hist_open(struct inode *inode, struct file *file) { + struct hist_file_data *hist_file; int ret; ret = tracing_open_file_tr(inode, file); if (ret) return ret; + hist_file = kzalloc(sizeof(*hist_file), GFP_KERNEL); + if (!hist_file) + return -ENOMEM; + hist_file->file = file; + /* Clear private_data to avoid warning in single_open() */ file->private_data = NULL; - return single_open(file, hist_show, file); + ret = single_open(file, hist_show, hist_file); + if (ret) + kfree(hist_file); + return ret; } const struct file_operations event_hist_fops = { .open = event_hist_open, .read = seq_read, .llseek = seq_lseek, - .release = tracing_single_release_file_tr, + .release = event_hist_release, + .poll = event_hist_poll, }; #ifdef CONFIG_HIST_TRIGGERS_DEBUG From patchwork Sun Aug 18 13:18:43 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Masami Hiramatsu (Google)" X-Patchwork-Id: 13767448 X-Patchwork-Delegate: mhiramat@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 BF6E977113; Sun, 18 Aug 2024 13:18:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723987127; cv=none; b=pKm+3rTcNY+BfP22piXxNfkXpXxfVzJxunMZWh1wQX21xBWzWoUAhCR9W0Zl78R97LE9bj2xsH6eGTcJxJ2nHxonS5oPpYQh0ivDCI0yX6eTFMMT2aO9G9h+/5EMj98aat0ew6UmYhn0DNOVcqpoAJcuWFOqVHhnw9mQCHaO1ug= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723987127; c=relaxed/simple; bh=Jur8XeuZlryZD5nLURpFedzGOoXyD7Nm8ATeE/V8NpA=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=nNybJUG6C9gCQvBNOAkc8dqcV6NtYTKJWrKkKgPsIeELyi3SVQcSqpZbnIbUZMTBSVe4vicLcaZQ57STGQ3ZlyrjjG9Y//vcGIefhwzDK/xa0NswHogokgDwnygag1GosZ8TFPM8kKqFz4/o9bvqZqZSZTexxYz98oLJl7dH5yc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=M7AZmTLm; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="M7AZmTLm" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A3EF8C32786; Sun, 18 Aug 2024 13:18:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1723987127; bh=Jur8XeuZlryZD5nLURpFedzGOoXyD7Nm8ATeE/V8NpA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=M7AZmTLmnRGlDFxYk+/jMEkQxUbI3xnr5nkV7Q5Abes34BJaGuY8s3eU7pXdEKIAB 5l9Q05hbBReBM7OKWBQOAp2zF8Zwb0BwzO7i4jrIxrjJrvuR1xmhCnTGr7D/iI4gzd FP35dIrBV2uX6CnrjbJ82RFP42X26n0uofSR8FxsBP4Z2vUcdCJYsfu7UO04kknGbr atJf6TGWCVeRODLi+4UtVj+Jy6CbQruy2QFiL055rdyey5g7UtnyG0dH6lsu9dRpwn opIOaPcwbxmTgB/PV2cucmDLP/kaaOOhJ5jtbjzkORqEZP01dnXmYR3d6JxO9ugvWJ ikyk2svJoC/sA== From: "Masami Hiramatsu (Google)" To: Steven Rostedt , Shuah Khan Cc: Masami Hiramatsu , Tom Zanussi , Mathieu Desnoyers , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: [PATCH v5 2/3] tracing/hist: Support POLLPRI event for poll on histogram Date: Sun, 18 Aug 2024 22:18:43 +0900 Message-Id: <172398712354.295714.14480056153369400862.stgit@devnote2> X-Mailer: git-send-email 2.34.1 In-Reply-To: <172398710447.295714.4489282566285719918.stgit@devnote2> References: <172398710447.295714.4489282566285719918.stgit@devnote2> User-Agent: StGit/0.19 Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Masami Hiramatsu (Google) Since POLLIN will not be flashed until read the hist file, user needs to repeat read() and poll() on hist for monitoring the event continuously. But the read() is somewhat redundant only for monitoring events. This add POLLPRI poll event on hist, this event returns when a histogram is updated after open(), poll() or read(). Thus it is possible to wait next event without read(). Signed-off-by: Masami Hiramatsu (Google) Reviewed-by: Tom Zanussi --- kernel/trace/trace_events_hist.c | 29 +++++++++++++++++++++++++++-- 1 file changed, 27 insertions(+), 2 deletions(-) diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index d27b60f54f68..d64aa34892e7 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -5599,6 +5599,7 @@ static void hist_trigger_show(struct seq_file *m, struct hist_file_data { struct file *file; u64 last_read; + u64 last_act; }; static u64 get_hist_hit_count(struct trace_event_file *event_file) @@ -5636,6 +5637,11 @@ static int hist_show(struct seq_file *m, void *v) hist_trigger_show(m, data, n++); } hist_file->last_read = get_hist_hit_count(event_file); + /* + * Update last_act too so that poll()/POLLPRI can wait for the next + * event after any syscall on hist file. + */ + hist_file->last_act = hist_file->last_read; out_unlock: mutex_unlock(&event_mutex); @@ -5649,6 +5655,7 @@ static __poll_t event_hist_poll(struct file *file, struct poll_table_struct *wai struct seq_file *m = file->private_data; struct hist_file_data *hist_file = m->private; __poll_t ret = 0; + u64 cnt; mutex_lock(&event_mutex); @@ -5660,8 +5667,13 @@ static __poll_t event_hist_poll(struct file *file, struct poll_table_struct *wai poll_wait(file, &event_file->hist_wq, wait); - if (hist_file->last_read != get_hist_hit_count(event_file)) - ret = EPOLLIN | EPOLLRDNORM; + cnt = get_hist_hit_count(event_file); + if (hist_file->last_read != cnt) + ret |= EPOLLIN | EPOLLRDNORM; + if (hist_file->last_act != cnt) { + hist_file->last_act = cnt; + ret |= EPOLLPRI; + } out_unlock: mutex_unlock(&event_mutex); @@ -5680,6 +5692,7 @@ static int event_hist_release(struct inode *inode, struct file *file) static int event_hist_open(struct inode *inode, struct file *file) { + struct trace_event_file *event_file; struct hist_file_data *hist_file; int ret; @@ -5690,13 +5703,25 @@ static int event_hist_open(struct inode *inode, struct file *file) hist_file = kzalloc(sizeof(*hist_file), GFP_KERNEL); if (!hist_file) return -ENOMEM; + + mutex_lock(&event_mutex); + event_file = event_file_data(file); + if (!event_file) { + ret = -ENODEV; + goto out_unlock; + } + hist_file->file = file; + hist_file->last_act = get_hist_hit_count(event_file); /* Clear private_data to avoid warning in single_open() */ file->private_data = NULL; ret = single_open(file, hist_show, hist_file); + +out_unlock: if (ret) kfree(hist_file); + mutex_unlock(&event_mutex); return ret; } From patchwork Sun Aug 18 13:18:53 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Masami Hiramatsu (Google)" X-Patchwork-Id: 13767449 X-Patchwork-Delegate: mhiramat@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 8E2BA1B978; Sun, 18 Aug 2024 13:18:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; 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Sun, 18 Aug 2024 13:18:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1723987137; bh=fH0kpLtUOttFyGNx+llSY9Yf0sAa021adABVn3AZlG0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZSc6UKjawLkikgx1pojN6BDqvAGZ+dgxo1Dy/E0dtGT/7AN7/nwRHKkx4ak43X9J7 40FBhv6ldE0tcqX0j6m744goDIuuJj+VhZe40sWRct/7J7Qa5FsVxm/tkzwRKgeyNl ciAaUxJH9xcyBX0HhCTkFYKeZ4evAjP7NN8uKZmUctrrD9IOqyKVrEwjsdw8hIv/Uc 9K4sfrERyIfw7MvL1n0sv1F7SiWjviTyxTk6upzaqvzYJR643bafyWm+FiOftTpT/O Dw4GQn6iE/IBn7PkTiGAGMW4b9CePh5htBpmAy7eNirjjpMCSFzcfH/G19uQvqd5b6 En+gDMDqV2Mww== From: "Masami Hiramatsu (Google)" To: Steven Rostedt , Shuah Khan Cc: Masami Hiramatsu , Tom Zanussi , Mathieu Desnoyers , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: [PATCH v5 3/3] selftests/tracing: Add hist poll() support test Date: Sun, 18 Aug 2024 22:18:53 +0900 Message-Id: <172398713342.295714.14169750905476040792.stgit@devnote2> X-Mailer: git-send-email 2.34.1 In-Reply-To: <172398710447.295714.4489282566285719918.stgit@devnote2> References: <172398710447.295714.4489282566285719918.stgit@devnote2> User-Agent: StGit/0.19 Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Masami Hiramatsu (Google) Add a testcase for poll() on hist file. This introduces a helper binary to the ftracetest, because there is no good way to reliably execute poll() on hist file. Signed-off-by: Masami Hiramatsu (Google) Reviewed-by: Shuah Khan --- Changes in v5: - Update comment about timeout. Changes in v4: - Use getopt() in poll.c (command options are changed) - Update test code according to the new command options. Changes in v2: - Update poll command to support both of POLLIN and POLLPRI, and timeout. - Identify unsupported stable kernel if poll-in returns soon. - Test both of POLLIN and POLLPRI. --- tools/testing/selftests/ftrace/Makefile | 2 + tools/testing/selftests/ftrace/poll.c | 74 ++++++++++++++++++++ .../ftrace/test.d/trigger/trigger-hist-poll.tc | 74 ++++++++++++++++++++ 3 files changed, 150 insertions(+) create mode 100644 tools/testing/selftests/ftrace/poll.c create mode 100644 tools/testing/selftests/ftrace/test.d/trigger/trigger-hist-poll.tc diff --git a/tools/testing/selftests/ftrace/Makefile b/tools/testing/selftests/ftrace/Makefile index a1e955d2de4c..49d96bb16355 100644 --- a/tools/testing/selftests/ftrace/Makefile +++ b/tools/testing/selftests/ftrace/Makefile @@ -6,4 +6,6 @@ TEST_PROGS := ftracetest-ktap TEST_FILES := test.d settings EXTRA_CLEAN := $(OUTPUT)/logs/* +TEST_GEN_PROGS = poll + include ../lib.mk diff --git a/tools/testing/selftests/ftrace/poll.c b/tools/testing/selftests/ftrace/poll.c new file mode 100644 index 000000000000..53258f7515e7 --- /dev/null +++ b/tools/testing/selftests/ftrace/poll.c @@ -0,0 +1,74 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Simple poll on a file. + * + * Copyright (c) 2024 Google LLC. + */ + +#include +#include +#include +#include +#include +#include +#include + +#define BUFSIZE 4096 + +/* + * Usage: + * poll [-I|-P] [-t timeout] FILE + */ +int main(int argc, char *argv[]) +{ + struct pollfd pfd = {.events = POLLIN}; + char buf[BUFSIZE]; + int timeout = -1; + int ret, opt; + + while ((opt = getopt(argc, argv, "IPt:")) != -1) { + switch (opt) { + case 'I': + pfd.events = POLLIN; + break; + case 'P': + pfd.events = POLLPRI; + break; + case 't': + timeout = atoi(optarg); + break; + default: + fprintf(stderr, "Usage: %s [-I|-P] [-t timeout] FILE\n", + argv[0]); + return -1; + } + } + if (optind >= argc) { + fprintf(stderr, "Error: Polling file is not specified\n"); + return -1; + } + + pfd.fd = open(argv[optind], O_RDONLY); + if (pfd.fd < 0) { + fprintf(stderr, "failed to open %s", argv[optind]); + perror("open"); + return -1; + } + + /* Reset poll by read if POLLIN is specified. */ + if (pfd.events & POLLIN) + do {} while (read(pfd.fd, buf, BUFSIZE) == BUFSIZE); + + ret = poll(&pfd, 1, timeout); + if (ret < 0 && errno != EINTR) { + perror("poll"); + return -1; + } + close(pfd.fd); + + /* If timeout happned (ret == 0), exit code is 1 */ + if (ret == 0) + return 1; + + return 0; +} diff --git a/tools/testing/selftests/ftrace/test.d/trigger/trigger-hist-poll.tc b/tools/testing/selftests/ftrace/test.d/trigger/trigger-hist-poll.tc new file mode 100644 index 000000000000..cbd01a71ecad --- /dev/null +++ b/tools/testing/selftests/ftrace/test.d/trigger/trigger-hist-poll.tc @@ -0,0 +1,74 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0 +# description: event trigger - test poll wait on histogram +# requires: set_event events/sched/sched_process_free/trigger events/sched/sched_process_free/hist +# flags: instance + +POLL=${FTRACETEST_ROOT}/poll + +if [ ! -x ${POLL} ]; then + echo "poll program is not compiled!" + exit_unresolved +fi + +EVENT=events/sched/sched_process_free/ + +# Check poll ops is supported. Before implementing poll on hist file, it +# returns soon with POLLIN | POLLOUT, but not POLLPRI. + +# This must wait >1 sec and return 1 (timeout). +set +e +${POLL} -I -t 1000 ${EVENT}/hist +ret=$? +set -e +if [ ${ret} != 1 ]; then + echo "poll on hist file is not supported" + exit_unsupported +fi + +# Test POLLIN +echo > trace +echo "hist:key=comm" > ${EVENT}/trigger +echo 1 > ${EVENT}/enable + +# This sleep command will exit after 2 seconds. +sleep 2 & +BGPID=$! +# if timeout happens, poll returns 1. +${POLL} -I -t 4000 ${EVENT}/hist +echo 0 > tracing_on + +if [ -d /proc/${BGPID} ]; then + echo "poll exits too soon" + kill -KILL ${BGPID} ||: + exit_fail +fi + +if ! grep -qw "sleep" trace; then + echo "poll exits before event happens" + exit_fail +fi + +# Test POLLPRI +echo > trace +echo 1 > tracing_on + +# This sleep command will exit after 2 seconds. +sleep 2 & +BGPID=$! +# if timeout happens, poll returns 1. +${POLL} -P -t 4000 ${EVENT}/hist +echo 0 > tracing_on + +if [ -d /proc/${BGPID} ]; then + echo "poll exits too soon" + kill -KILL ${BGPID} ||: + exit_fail +fi + +if ! grep -qw "sleep" trace; then + echo "poll exits before event happens" + exit_fail +fi + +exit_pass