Messages in this thread |  | | From | "Rafael J. Wysocki" <> | Subject | Re: [PATCH v3] PM / wakeup: use seq_open() to show wakeup stats | Date | Sun, 13 May 2018 10:46:57 +0200 |
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On Wednesday, April 25, 2018 12:59:31 PM CEST Ganesh Mahendran wrote: > 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 <opensource.ganesh@gmail.com> > ---- > 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) >
Applied, thanks!
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