Messages in this thread |  | | Date | Sun, 29 Apr 2018 16:30:02 +0200 | From | Pavel Machek <> | Subject | Re: [PATCH v3] PM / wakeup: use seq_open() to show wakeup stats |
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On Wed 2018-04-25 18:59:31, 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.
Sounds like magic.
> -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) > { ... > - 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_stop(struct seq_file *m, void *v) > +{ > + int *srcuidx = m->private; > + > + srcu_read_unlock(&wakeup_srcu, *srcuidx); > +}
But you are holding srcu_lock over return to userspace, and somehow I don't think that's permitted? Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html [unhandled content-type:application/pgp-signature] |  |