Re: [PATCH, v6 2/3] Implement timer slack notifier chain
From: Thomas Gleixner <hidden>
Date: 2011-02-14 13:32:58
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On Mon, 14 Feb 2011, Kirill A. Shutsemov wrote:
From: Kirill A. Shutemov <redacted> Process can change its timer slack using prctl(). Timer slack notifier call chain allows to react on such change or forbid it.
So we add a notifier call chain and more exports to allow what ?
quoted hunk ↗ jump to hunk
--- a/kernel/sys.c +++ b/kernel/sys.c@@ -1691,15 +1691,10 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3, error = perf_event_task_enable(); break; case PR_GET_TIMERSLACK: - error = current->timer_slack_ns; + error = prctl_get_timer_slack();
What's the point of replacing current->timer_slack_ns with a function which does exactly the same ?
+long prctl_set_timer_slack(long timer_slack_ns)
+{
+ int err;
+
+ /* Reset timer slack to default value */
+ if (timer_slack_ns <= 0) {
+ current->timer_slack_ns = current->default_timer_slack_ns;
+ return 0;That does not make any sense at all. Why is setting default_timer_slack_ns not subject to validation ? Why is it treaded seperately ?
+ } + + err = blocking_notifier_call_chain(&timer_slack_notify_list, + timer_slack_ns, NULL); + if (err == NOTIFY_DONE) + current->timer_slack_ns = timer_slack_ns; + + return notifier_to_errno(err);
Thanks, tglx