linux-kernel - Re: [PATCH v3] hrtimer: avoid retrigger_next

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 linux-cve-announce 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:   Thu, 15 Apr 2021 20:59:30 +0200
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Marcelo Tosatti <mtosatti@...hat.com>
Cc:     Anna-Maria Behnsen <anna-maria@...utronix.de>,
        linux-kernel@...r.kernel.org,
        Frederic Weisbecker <frederic@...nel.org>,
        Peter Xu <peterx@...hat.com>,
        Nitesh Narayan Lal <nitesh@...hat.com>,
        Alex Belits <abelits@...vell.com>
Subject: Re: [PATCH v3] hrtimer: avoid retrigger_next_event IPI

On Thu, Apr 15 2021 at 12:39, Marcelo Tosatti wrote:
> +static bool need_reprogram_timer(struct hrtimer_cpu_base *cpu_base)
> +{
> +	unsigned int active = 0;
> +
> +	if (cpu_base->softirq_activated)
> +		return true;
> +
> +	active = cpu_base->active_bases & HRTIMER_ACTIVE_SOFT;
> +	active = active | (cpu_base->active_bases & HRTIMER_ACTIVE_HARD);

It's not entirely clear to me what that 'active' variable business above
is doing and why it's needed at all. But I might be missing something.

> +	return (cpu_base->active_bases & CLOCK_SET_BASES) != 0;
> +}