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
| ||
|
Date: Mon, 17 Aug 2020 11:03:10 +0900 From: Sergey Senozhatsky <sergey.senozhatsky@...il.com> To: Will Deacon <will@...nel.org>, Marc Zyngier <maz@...nel.org> Cc: James Morse <james.morse@....com>, Julien Thierry <julien.thierry.kdev@...il.com>, Suzuki K Poulose <suzuki.poulose@....com>, suleiman@...gle.com, joelaf@...gle.com, linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.cs.columbia.edu, linux-kernel@...r.kernel.org, Sergey Senozhatsky <sergey.senozhatsky@...il.com> Subject: Re: [RFC][PATCH 0/4] arm64:kvm: teach guest sched that VCPUs can be preempted 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. Hi, A gentle ping. -ss
Powered by blists - more mailing lists