From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: ARC-Seal: i=1; a=rsa-sha256; t=1524653991; cv=none; d=google.com; s=arc-20160816; b=iRFgsp42QlQv5rC8q13I8QyZjVxfMvis6uE9/J2VYywWi2Ryc1tnpZPksncawhc/nd q0znYbTL5c7n+uY1IvLCrJdtqdNaOD227ysaEvGmXMOY3vV2opD4F7F/8SglJhy2FTTf eohvyoizZUjxx0azmkkAcvJohQYtUkTsauPowM4/xZtlFRCziOAM5MPTxPp/6oWt7ZW5 e7/Wzk1fI5V8QFlaJTvplq9OPixKTnzA1fh05zXYx0LwQSjgbsraJi8GhSpxQwSUhF/n 2d1iBzwMFC/6rtgHJn63jDsFypigwOdsuYz1wGQPcu72PAruz47fJTpYd4Pk4TlKSLnM t7CA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=message-id:date:subject:cc:to:from:dkim-signature :arc-authentication-results; bh=+YSK0If6uDJ4RXABIIMZbZ61AcmWkpQ4NLM5aaDPbFk=; b=xS71/NyC7fGQh3qwnoGYCtBnR/Nfjevr3jfzEIKm3R1AaFZtWK/+QWa47H8C0mKKc9 2zHjxQ2TMWKQN8UVJI1RxAEUl86dY355XO//gByetOjEndQJexAmL3SWcgmELhGap6Wz KbWtzUOg1JWnDQKJorCIba6q/t2ySe2IUhF3fNUZugHhMiRmecYav51daJC2altfc4Sz DFFRt3daFEkvmb514mlAYpo0PLwWOOeLJZx4F1fXsyZlZMrFmb5gHKRu3pNK9/9OoFGX yN1HRHVDrFjo1AlttJZ/mT4xrj2LR3Pa6Zr7luDf1p2lrkVqiGTDinBGQ2v1WDYhbPt4 iI2Q== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=TWKjFWeZ; spf=pass (google.com: domain of opensource.ganesh@gmail.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=opensource.ganesh@gmail.com; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=TWKjFWeZ; spf=pass (google.com: domain of opensource.ganesh@gmail.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=opensource.ganesh@gmail.com; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com X-Google-Smtp-Source: AIpwx49NtScbSQCWoJGXX6lC2mJPHoBae8HaJ9GxOMJjry7zy/kbOILTxfHYLsokJEMqtt5cZJj21w== From: Ganesh Mahendran To: rjw@rjwysocki.net, pavel@ucw.cz, len.brown@intel.com, rafael@kernel.org, gregkh@linuxfoundation.org, geert@linux-m68k.org Cc: linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, Ganesh Mahendran Subject: [PATCH v3] PM / wakeup: use seq_open() to show wakeup stats Date: Wed, 25 Apr 2018 18:59:31 +0800 Message-Id: <1524653971-10425-1-git-send-email-opensource.ganesh@gmail.com> X-Mailer: git-send-email 1.9.1 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1598715584055641513?= X-GMAIL-MSGID: =?utf-8?q?1598715584055641513?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 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 ---- v3: simplify wakeup_sources_stats_seq_start v2: use srcu_read_lock instead of rcu_read_lock --- drivers/base/power/wakeup.c | 75 +++++++++++++++++++++++++++++++++++---------- 1 file changed, 59 insertions(+), 16 deletions(-) diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c index ea01621..5872705 100644 --- a/drivers/base/power/wakeup.c +++ b/drivers/base/power/wakeup.c @@ -1029,32 +1029,75 @@ 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) + return ws; + } + + return NULL; +} + +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 +1105,7 @@ 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) -- 1.9.1