lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Fri, 11 Apr 2014 16:33:42 -0400 (EDT)
From:	David Miller <davem@...emloft.net>
To:	riel@...hat.com
Cc:	linux-kernel@...r.kernel.org, netdev@...r.kernel.org,
	jbenc@...hat.com, peterz@...radead.org, tglx@...utronix.de,
	fweisbec@...il.com
Subject: Re: [PATCH] softirq: punt to ksoftirqd if __do_softirq recently
 looped

From: Rik van Riel <riel@...hat.com>
Date: Thu, 10 Apr 2014 11:57:06 -0400

> @@ -330,7 +334,11 @@ void irq_enter(void)
>  
>  static inline void invoke_softirq(void)
>  {
> -	if (!force_irqthreads) {
> +	/*
> +	 * If force_irqthreads is set, or if we looped in __do_softirq this
> +	 * jiffie, punt to ksoftirqd to prevent userland starvation.
> +	 */
> +	if (!force_irqthreads && this_cpu_read(softirq_looped) != jiffies) {

If we do this, which I'm not convinced of yet, I think we should use two
jiffies as the cutoff.

Because if we are at the tail end of one jiffie we'll prematurely go to
ksoftirqd when we really have no reason to do so.
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Powered by blists - more mailing lists