From patchwork Wed Aug 14 00:11:24 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: 819284 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 5EC222901; Wed, 14 Aug 2024 00:11:28 +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=1723594288; cv=none; b=V/cu9Io0XakTZ+RBlBrrxXWj0fW/vbC3VQVgUXio7xUu3EH3/3EzLMY4q9mC8D9BPQguJndkiZZ60177GHzzVv/7R5KkbR8egdVeyA1ciPQpwRokfvEM/nT1ke/AFC4GkHOvWGDNV/3anSbFlrHEXfBuMdkwixyZdmMMig5wlQs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723594288; c=relaxed/simple; bh=PduHRgfMp3qDtlIlUMaJZfdj3y/ud8IXpCM0H4jkdiM=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=OX5EvUWesOToXE4Acc4B89JM3I0gTsM9wv15gQMPaFN0DpTpvB0AfMSAiumeZxrenbon/6VSJd4zoG5rXNuLsMrOYyNogY1kR7JnLNYQz5hOXPW0fe8E+tkFooiAlc1YeQ6Qck06BKYyWkwEy6Qe7X2EaJiOFx8HfP5vMBB093k= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=oPqaJ7QS; 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="oPqaJ7QS" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 96402C32782; Wed, 14 Aug 2024 00:11:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1723594288; bh=PduHRgfMp3qDtlIlUMaJZfdj3y/ud8IXpCM0H4jkdiM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=oPqaJ7QS3VOFcIlhjBGTAlFHglF/8UnBzdBS4p4m4a6LbNQlGVn3SCMnCMkJglj4t hiMvjojhXt2yrmF6GEQDxyBO9s8/nGA7yZWoL1pcJiCKjZgWGf06y827RQqOxSuuzl fbracmVx6cGaHdNSf6Ju26pttOQFP/DUM16ZGPgSZgjRc/jBgV5GGAZ+HC4LfTceYE +CWV8KoMefcjI4v0QN0TOONGZ4ytaUg9I+FrBj7LxNG+cpyB3RueudwbdaCWmGtcXN hNgv+RjRfUhPp2E93Bll/Yt00nzx1aWMHhWJIv06PW65zM13thjWtsJI9sAioAFLQ9 KAh7TlU5NlEkQ== 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 v3 1/3] tracing/hist: Add poll(POLLIN) support on hist file Date: Wed, 14 Aug 2024 09:11:24 +0900 Message-Id: <172359428405.323666.13595084292942408031.stgit@devnote2> X-Mailer: git-send-email 2.34.1 In-Reply-To: <172359427367.323666.6446548762874507863.stgit@devnote2> References: <172359427367.323666.6446548762874507863.stgit@devnote2> User-Agent: StGit/0.19 Precedence: bulk X-Mailing-List: linux-kselftest@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 Wed Aug 14 00:11:33 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: 819621 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 3AF702594; Wed, 14 Aug 2024 00:11:37 +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=1723594298; cv=none; b=gzYi9WCELGzWDCrfPFsFsIJMsUnVmmaCkoFqfBX7yI+aElLX8PN/cIsgByNHpH+bO/tqWIh28U7kjaMiX0J5V6vw5jZh0UV5wECFjIPbyW2JQlfu4GFbQZbPgzluSOS6xnxUq6KyLWrjO4unrsXLa0ZbYcGi1jncUVUpyH/rC+c= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723594298; c=relaxed/simple; bh=Jur8XeuZlryZD5nLURpFedzGOoXyD7Nm8ATeE/V8NpA=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=S991qMHZ2UiDMhh72l2o9aO3DhJnF78BlalZZsw4XglCvKuDHj2qG8G0saSe7oPuBTd4XbCQRuR8sDuRaCpGcfnUEbEuoOGWvmvIxzdPuSx75rAwsSlqHI0CFQpWyhx3EmEw8Q9RUBDKfyBZ4AeS8VIKH7ck0nKi2/ktCAgFXaY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=N/rZEM60; 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="N/rZEM60" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E4CEDC4AF0C; Wed, 14 Aug 2024 00:11:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1723594297; bh=Jur8XeuZlryZD5nLURpFedzGOoXyD7Nm8ATeE/V8NpA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=N/rZEM60+o93h9aJhJDoC41rvH6xN+00+lWdrNeaEDHDewuxlaEEJtFov1QltISts J2xbHmkTZ2P60R2ig07lugI03BpBH+ctu4GRCCZlKlaj7dvDNzJdRzXuMji9QkPQQV vrc1fmdIK8VUMhrjgaxYaDSRNKhm3A1vlAsUnZsZf6+73Z42wrCNc/SAXj2wViedBG NA8qb69i/RgXie+SSj2Dv/xnnsaDS5K2SZUCTb4JB+c+o+F0zEpdUYM8DnMJ6QY9Mb oQJ6gd2FTofJNDALVJOUUlKFerJmP//TidJuPj/zV1R4VlTGKsOB7tvUjWaduYOJ9g 1UFT4U7DJ8cbA== 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 v3 2/3] tracing/hist: Support POLLPRI event for poll on histogram Date: Wed, 14 Aug 2024 09:11:33 +0900 Message-Id: <172359429363.323666.2642075317101942614.stgit@devnote2> X-Mailer: git-send-email 2.34.1 In-Reply-To: <172359427367.323666.6446548762874507863.stgit@devnote2> References: <172359427367.323666.6446548762874507863.stgit@devnote2> User-Agent: StGit/0.19 Precedence: bulk X-Mailing-List: linux-kselftest@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 Wed Aug 14 00:11:43 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: 819283 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 9598F8460; Wed, 14 Aug 2024 00:11:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; 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Wed, 14 Aug 2024 00:11:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1723594307; bh=qMUrvkxecOx/v3yAVcd4bfohhjch6A/wjtM7rqSvV/g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VnG9KMjJ42Oc4ohmoc45h9to5g8LhrCZUah5TyAFfAyVVXNtHVR/TSnYqddsfCKdd ayS5izpO2Y9lUysZO8+5stYd3JmImH5yatDY4Q1IcPOdEXw9k4CArycy2KFp2mJ+Xv Max0JENKQWPyhkuhQGZ/hyraIEmPKSZSfudjtOqcoela64fLx6CYQ79rYjwFPfzbZT QzVTOFrFiUGhw1r4XYKlYuZGYOJuWWXzRz0tzDRGGpfOVjzn0h0fGmb7MhQQZ0eTfj vGjpMpaUzZvqMN3namnzgQg0zVotiQXnpQCqY0nVnrcPuTyhccnhOOzsk7V9l/Y7Ed lJNfMDeda2r0Q== 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 v3 3/3] selftests/tracing: Add hist poll() support test Date: Wed, 14 Aug 2024 09:11:43 +0900 Message-Id: <172359430351.323666.9768554440535494357.stgit@devnote2> X-Mailer: git-send-email 2.34.1 In-Reply-To: <172359427367.323666.6446548762874507863.stgit@devnote2> References: <172359427367.323666.6446548762874507863.stgit@devnote2> User-Agent: StGit/0.19 Precedence: bulk X-Mailing-List: linux-kselftest@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) --- 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 | 62 +++++++++++++++++ .../ftrace/test.d/trigger/trigger-hist-poll.tc | 74 ++++++++++++++++++++ 3 files changed, 138 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 := $(OUTPUT)/logs/* +TEST_GEN_PROGS = poll + include ../lib.mk diff --git a/tools/testing/selftests/ftrace/poll.c b/tools/testing/selftests/ftrace/poll.c new file mode 100644 index 000000000000..8003a59fe042 --- /dev/null +++ b/tools/testing/selftests/ftrace/poll.c @@ -0,0 +1,62 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Simple poll on a file. + * + * Copyright (c) 2024 Google LLC. + */ + +#include +#include +#include +#include +#include +#include +#include + +#define BUFSIZE 4096 + +/* + * Usage: + * poll [timeout] + */ +int main(int argc, char *argv[]) +{ + struct pollfd pfd; + char buf[BUFSIZE]; + int timeout = -1; + int ret; + + if (argc < 3) + return -1; + + if (!strcmp(argv[1], "in")) + pfd.events = POLLIN; + else if (!strcmp(argv[1], "pri")) + pfd.events = POLLPRI; + + pfd.fd = open(argv[2], O_RDONLY); + if (pfd.fd < 0) { + perror("open"); + return -1; + } + + if (argc == 4) + timeout = atoi(argv[3]); + + /* Reset poll by read if POLLIN is specified. */ + if (pfd.events & POLLIN) + do {} while (read(pfd.fd, buf, BUFSIZE) == BUFSIZE); + + ret = poll(&pfd, 1, timeout); + if (ret < 0 && errno != EINTR) { + perror("poll"); + return -1; + } + close(pfd.fd); + + /* If timeout happned, return code is 0 */ + if (ret == 0) + return 1; + + return 0; +} diff --git a/tools/testing/selftests/ftrace/test.d/trigger/trigger-hist-poll.tc b/tools/testing/selftests/ftrace/test.d/trigger/trigger-hist-poll.tc new file mode 100644 index 000000000000..53bea74e2234 --- /dev/null +++ b/tools/testing/selftests/ftrace/test.d/trigger/trigger-hist-poll.tc @@ -0,0 +1,74 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0 +# description: event trigger - test poll wait on histogram +# requires: set_event events/sched/sched_process_free/trigger events/sched/sched_process_free/hist +# flags: instance + +POLL=${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} in ${EVENT}/hist 1000 +ret=$? +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} in ${EVENT}/hist 4000 +echo 0 > tracing_on + +if [ -d /proc/${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} pri ${EVENT}/hist 4000 +echo 0 > tracing_on + +if [ -d /proc/${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