Re: [PATCH v3] mm: vmscan: abort proactive reclaim early when freezing for suspend

[Oleg Nesterov <oleg@redhat.com>]

On 07/17, Richard Chang wrote:
>
> v3: Return -ERESTARTSYS instead of -EINTR in user_proactive_reclaim

Yes, this change LGTM, but ...

> +		/*
> +		 * Return -ERESTARTSYS to allow the freezer to interrupt the
> +		 * task. The syscall will be transparently restarted upon
> +		 * resume. Real signals (e.g. SIGINT) will be automatically
> +		 * converted to -EINTR by the signal layer.
> +		 */

... the comment looks a bit misleading...

So, if the signal is "real" and has a handler, handle_signal() does

		case -ERESTARTSYS:
			if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
				regs->ax = -EINTR;
				break;
			}
			fallthrough;
		case -ERESTARTNOINTR:
			regs->ax = regs->orig_ax;
			regs->ip -= 2;
			break;

If SA_RESTART is set, the syscall will be restarted after return from
signal handler.

Oleg.