Re: [RFC][PATCH -mm 2/6] Freezer: Do not send signals to kernel threads

[Pavel Machek <pavel@ucw.cz>]

Hi!

> From: Rafael J. Wysocki <rjw@sisk.pl>
> 
> Commit b74d0deb968e1f85942f17080eace015ce3c332c has changed
> recalc_sigpending_tsk() so that it doesn't clear TIF_SIGPENDING.  For this
> reason, the freezer should not send fake signals to kernel threads any more,
> since otherwise some of them may run with TIF_SIGPENDING set forever if the
> freezing of kernel threads fails.

Is there some bigger plan why we want this?

I mean, it seems nicer w/o signals, but OTOH it is more lines of code
and kernel/user freezing diverges. Can we just revert few lines,
instead of inserting 100 lines?

> +/*
> + * Freezer-friendly wrappers around wait_event_interruptible() and
> + * wait_event_interruptible_timeout(), originally defined in <linux/wait.h>
> + */
> +
> +#define wait_event_freezable(wq, condition)				\
> +({									\
> +	int __ret;							\
> +	do {								\
> +		__ret = wait_event_interruptible(wq, 			\
> +				(condition) || freezing(current));	\
> +	} while (try_to_freeze());					\
> +	__ret;								\
> +})
> +
> +
> +#define wait_event_freezable_timeout(wq, condition, timeout)		\
> +({									\
> +	long __ret = timeout;						\
> +	do {								\
> +		__ret = wait_event_interruptible_timeout(wq,		\
> +				(condition) || freezing(current),	\
> +				__ret); 				\
> +	} while (try_to_freeze());					\
> +	__ret;								\
> +})

Hohum, but yes, these are nice.

								Pavel

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html