From patchwork Mon Mar 5 08:47:46 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mahendran Ganesh X-Patchwork-Id: 10258383 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 37A396037E for ; Mon, 5 Mar 2018 08:48:12 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 27758288DC for ; Mon, 5 Mar 2018 08:48:12 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 1BAB128935; Mon, 5 Mar 2018 08:48:12 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, FREEMAIL_FROM, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 9E406288DC for ; Mon, 5 Mar 2018 08:48:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932930AbeCEIsK (ORCPT ); Mon, 5 Mar 2018 03:48:10 -0500 Received: from mail-pf0-f194.google.com ([209.85.192.194]:37208 "EHLO mail-pf0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932892AbeCEIsJ (ORCPT ); Mon, 5 Mar 2018 03:48:09 -0500 Received: by mail-pf0-f194.google.com with SMTP id h11so6524904pfn.4; Mon, 05 Mar 2018 00:48:09 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=USs2LPnnBPP+a4qHzLgEt7V9iKhpQMPa1x6WyQCHWnQ=; b=eHJZUvkWxg/MNL7K60LN/OtrtBte+pJOhyf+/BI16m88S9CeFV0W17fnpYOOZyrzBc j3C37rCXanh7DxvsGZEH+DCWsanblCI568NuBbCZDaRTiaddyqEo3MhiiF8iAfh1KiAH gTtVGIqxpWINTm8WmGfEOe9+dy0JbdPdfDFDCsfBvZVGFIlxL+JqoOrhc78TuxWeX2Q8 KbQrLBgAou7Z7hHYj6xGNv63hIlOUIaQGDzG75uRVlOtR/l29HheNaY/kQgN1xlbTI6R 7h/st0FUaQaTsnl2W4InM3vkdtEuTUmk4FqzJOPogUrccODAX3AjYEYd3oAAUidS8N55 NoOg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=USs2LPnnBPP+a4qHzLgEt7V9iKhpQMPa1x6WyQCHWnQ=; b=rgOPY/CRW98uPCeRu6Yru177WDBlnpA6Z2FwI4N6wM+DqugzxbaXLP/CUpz8lQ4jn5 7Ua6I+K5+TA3QqUDI2m8F6rD6MwyhMaVD1oAzvD5eefDhpfi7MH8iwaca+uRkWHivSb9 BUvgAdQM2TTbpWYZBh+mCbjWG1lLmybdI3Zhl7z2+weJRSe9n7+A2vLW52aKXFBjndCU dj8ezveBKoXvUQjvt2yJN2gJ6QvR983b1/exT2kz9eF0yn7eRXWu5lK48WrT8Y2mmk4k pv94FAz6J1/pZwrehPlVogY4aoc3uRwc7tg7kwbtivy/iKDX2pvJdl0xq7AZBi2j4WrG D+ZQ== X-Gm-Message-State: APf1xPBTyssfyYiuvmHVryEFXRsJgM1VEW54/dgZf7/gTk0g2gR8YceA 8FXFtlUGbVYC6mc01ZFX/Q7wNw== X-Google-Smtp-Source: AG47ELvCa2Per4e6oyPV581thAZN8Vj7q17SrgHusi4jyEBt9mzd+4bdGn9MkjAQ53zPrXN48TNxsA== X-Received: by 10.99.108.199 with SMTP id h190mr11615683pgc.295.1520239688907; Mon, 05 Mar 2018 00:48:08 -0800 (PST) Received: from localhost ([221.226.180.178]) by smtp.gmail.com with ESMTPSA id c14sm21015241pfn.185.2018.03.05.00.48.07 (version=TLS1_2 cipher=AES128-SHA bits=128/128); Mon, 05 Mar 2018 00:48:08 -0800 (PST) From: Ganesh Mahendran To: rjw@rjwysocki.net, pavel@ucw.cz, len.brown@intel.com, rafael@kernel.org, gregkh@linuxfoundation.org Cc: linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, Ganesh Mahendran Subject: [PATCH v2] PM / wakeup: use seq_open() to show wakeup stats Date: Mon, 5 Mar 2018 16:47:46 +0800 Message-Id: <1520239666-2964-1-git-send-email-opensource.ganesh@gmail.com> X-Mailer: git-send-email 1.9.1 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP single_open() interface requires that the whole output must fit into a single buffer. This will lead to timeout when system memory is not in a good situation. This patch use seq_open() to show wakeup stats. This method need only one page, so timeout will not be observed. Signed-off-by: Ganesh Mahendran ---- v2: use srcu_read_lock instead of rcu_read_lock --- drivers/base/power/wakeup.c | 77 +++++++++++++++++++++++++++++++++++---------- 1 file changed, 61 insertions(+), 16 deletions(-) diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c index ea01621..3bcab7d 100644 --- a/drivers/base/power/wakeup.c +++ b/drivers/base/power/wakeup.c @@ -1029,32 +1029,77 @@ static int print_wakeup_source_stats(struct seq_file *m, return 0; } -/** - * wakeup_sources_stats_show - Print wakeup sources statistics information. - * @m: seq_file to print the statistics into. - */ -static int wakeup_sources_stats_show(struct seq_file *m, void *unused) +static void *wakeup_sources_stats_seq_start(struct seq_file *m, + loff_t *pos) { struct wakeup_source *ws; - int srcuidx; + loff_t n = *pos; + int *srcuidx = m->private; - seq_puts(m, "name\t\tactive_count\tevent_count\twakeup_count\t" - "expire_count\tactive_since\ttotal_time\tmax_time\t" - "last_change\tprevent_suspend_time\n"); + if (n == 0) { + seq_puts(m, "name\t\tactive_count\tevent_count\twakeup_count\t" + "expire_count\tactive_since\ttotal_time\tmax_time\t" + "last_change\tprevent_suspend_time\n"); + } - srcuidx = srcu_read_lock(&wakeup_srcu); - list_for_each_entry_rcu(ws, &wakeup_sources, entry) - print_wakeup_source_stats(m, ws); - srcu_read_unlock(&wakeup_srcu, srcuidx); + *srcuidx = srcu_read_lock(&wakeup_srcu); + list_for_each_entry_rcu(ws, &wakeup_sources, entry) { + if (n-- > 0) + continue; + goto out; + } + ws = NULL; +out: + return ws; +} + +static void *wakeup_sources_stats_seq_next(struct seq_file *m, + void *v, loff_t *pos) +{ + struct wakeup_source *ws = v; + struct wakeup_source *next_ws = NULL; + + ++(*pos); - print_wakeup_source_stats(m, &deleted_ws); + list_for_each_entry_continue_rcu(ws, &wakeup_sources, entry) { + next_ws = ws; + break; + } + + return next_ws; +} + +static void wakeup_sources_stats_seq_stop(struct seq_file *m, void *v) +{ + int *srcuidx = m->private; + + srcu_read_unlock(&wakeup_srcu, *srcuidx); +} + +/** + * wakeup_sources_stats_seq_show - Print wakeup sources statistics information. + * @m: seq_file to print the statistics into. + * @v: wakeup_source of each iteration + */ +static int wakeup_sources_stats_seq_show(struct seq_file *m, void *v) +{ + struct wakeup_source *ws = v; + + print_wakeup_source_stats(m, ws); return 0; } +static const struct seq_operations wakeup_sources_stats_seq_ops = { + .start = wakeup_sources_stats_seq_start, + .next = wakeup_sources_stats_seq_next, + .stop = wakeup_sources_stats_seq_stop, + .show = wakeup_sources_stats_seq_show, +}; + static int wakeup_sources_stats_open(struct inode *inode, struct file *file) { - return single_open(file, wakeup_sources_stats_show, NULL); + return seq_open_private(file, &wakeup_sources_stats_seq_ops, sizeof(int)); } static const struct file_operations wakeup_sources_stats_fops = { @@ -1062,7 +1107,7 @@ static int wakeup_sources_stats_open(struct inode *inode, struct file *file) .open = wakeup_sources_stats_open, .read = seq_read, .llseek = seq_lseek, - .release = single_release, + .release = seq_release_private, }; static int __init wakeup_sources_debugfs_init(void)