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:   Mon, 17 Aug 2020 11:03:10 +0900
From:   Sergey Senozhatsky <>
To:     Will Deacon <>, Marc Zyngier <>
Cc:     James Morse <>,
        Julien Thierry <>,
        Suzuki K Poulose <>,,,,,,
        Sergey Senozhatsky <>
Subject: Re: [RFC][PATCH 0/4] arm64:kvm: teach guest sched that VCPUs can be

On (20/07/21 13:17), Sergey Senozhatsky wrote:
> Hello,
> 	RFC
> 	We noticed that in a number of cases when we wake_up_process()
> on arm64 guest we end up enqueuing that task on a preempted VCPU. The culprit
> appears to be the fact that arm64 guests are not aware of VCPU preemption
> as such, so when sched picks up an idle VCPU it always assumes that VCPU
> is available:
>       wake_up_process()
>        try_to_wake_up()
>         select_task_rq_fair()
>          available_idle_cpu()
>           vcpu_is_preempted()    // return false;
> Which is, obviously, not the case.
> This RFC patch set adds a simple vcpu_is_preempted() implementation so
> that scheduler can make better decisions when it search for the idle
> (v)CPU.


A gentle ping.


Powered by blists - more mailing lists