linux-kernel - Re: [PATCH 10/25] hrtimer: Make handling of hrtimer reprogramming and enqueuing not conditional

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:   Tue, 26 Sep 2017 14:14:35 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Anna-Maria Gleixner <anna-maria@...utronix.de>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        Ingo Molnar <mingo@...hat.com>,
        Christoph Hellwig <hch@....org>, keescook@...omium.org,
        John Stultz <john.stultz@...aro.org>,
        Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH 10/25] hrtimer: Make handling of hrtimer reprogramming
 and enqueuing not conditional

On Thu, Aug 31, 2017 at 12:23:38PM -0000, Anna-Maria Gleixner wrote:
> The hrtimer_reprogramming, remote timer enqueuing and handling of the
> hrtimer_cpu_base struct member expires_next depend on the active high
> resolution timers. This makes the code harder to understand.
> 
> To simplify the code, the hrtimer reprogramming is now executed
> independently except for the real reprogramming part. The expires_next
> stores now the first enqueued timer. Due to the adaption of the
> check_target function, remote enqueuing is now only possible when the
> expiry time is after the currently first expiry time independent of the
> active high resolution timers.

Sorry, very hard to follow. What?

So we do this to unconditionally track expire_next, such that we can
(later) use hrtimer_check_target()?