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
| ||
|
Date: Mon, 23 Oct 2017 13:12:43 +0800 From: Alex Shi <alex.shi@...aro.org> To: "Rafael J. Wysocki" <rjw@...ysocki.net>, Linux PM <linux-pm@...r.kernel.org> Cc: LKML <linux-kernel@...r.kernel.org>, Reinette Chatre <reinette.chatre@...el.com>, Ramesh Thomas <ramesh.thomas@...el.com>, Ulf Hansson <ulf.hansson@...aro.org> Subject: Re: [PATCH] PM / QoS: Fix device resume latency PM QoS On 10/20/2017 07:27 PM, Rafael J. Wysocki wrote: > From: Rafael J. Wysocki <rafael.j.wysocki@...el.com> > > The special value of 0 for device resume latency PM QoS means > "no restriction", but there are two problems with that. > > First, device resume latency PM QoS requests with 0 as the > value are always put in front of requests with positive > values in the priority lists used internally by the PM QoS > framework, causing 0 to be chosen as an effective constraint > value. However, that 0 is then interpreted as "no restriction" > effectively overriding the other requests with specific > restrictions which is incorrect. > > Second, the users of device resume latency PM QoS have no > way to specify that *any* resume latency at all should be > avoided, which is an artificial limitation in general. > > To address these issues, modify device resume latency PM QoS to > use S32_MAX as the "no constraint" value and 0 as the "no > latency at all" one and rework its users (the cpuidle menu > governor, the genpd QoS governor and the runtime PM framework) > to follow these changes. > > Also add a special "n/a" value to the corresponding user space I/F > to allow user space to indicate that it cannot accept any resume > latencies at all for the given device. > > Link: https://bugzilla.kernel.org/show_bug.cgi?id=197323 > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com> > Reported-by: Reinette Chatre <reinette.chatre@...el.com> Acked-by: Alex Shi <alex.shi@...aro.org>
Powered by blists - more mailing lists