linux-kernel - Re: [RFT][PATCH v2 1/2] PM / domains: Rework governor code to be more consistent

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:   Sun, 5 Nov 2017 23:47:50 -0800
From:   Ramesh Thomas <ramesh.thomas@...el.com>
To:     "Rafael J. Wysocki" <rafael@...nel.org>
Cc:     "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Linux PM <linux-pm@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        Tero Kristo <t-kristo@...com>,
        Reinette Chatre <reinette.chatre@...el.com>,
        Alex Shi <alex.shi@...aro.org>
Subject: Re: [RFT][PATCH v2 1/2] PM / domains: Rework governor code to be
 more consistent

On 2017-11-04 at 12:24:15 +0100, Rafael J. Wysocki wrote:
> On Sat, Nov 4, 2017 at 3:34 AM, Ramesh Thomas <ramesh.thomas@...el.com> wrote:
> > On 2017-11-03 at 12:47:20 +0100, Rafael J. Wysocki wrote:
> >> From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> >>
> >> The genpd governor currently uses negative PM QoS values to indicate
> >> the "no suspend" condition and 0 as "no restriction", but it doesn't
> >> use them consistently.  Moreover, it tries to refresh QoS values for
> >> already suspended devices in a quite questionable way.
> >>
> >> For the above reasons, rework it to be a bit more consistent.
> >>
> >> First off, note that dev_pm_qos_read_value() in
> >> dev_update_qos_constraint() and __default_power_down_ok() is
> >> evaluated for devices in suspend.  Moreover, that only happens if the
> >> effective_constraint_ns value for them is negative (meaning "no
> >> suspend").  It is not evaluated in any other cases, so effectively
> >> the QoS values are only updated for devices in suspend that should
> >> not have been suspended in the first place.  In all of the other
> >> cases, the QoS values taken into account are the effective ones from
> >> the time before the device has been suspended, so generally devices
> >> need to be resumed and suspended again for new QoS values to take
> >> effect anyway.  Thus evaluating dev_update_qos_constraint() in
> >> those two places doesn't make sense at all, so drop it.
> >>
> >> Second, initialize effective_constraint_ns to 0 ("no constraint")
> >> rather than to (-1) ("no suspend"), which makes more sense in
> >> general and in case effective_constraint_ns is never updated
> >> (the device is in suspend all the time or it is never suspended)
> >> it doesn't affect the device's parent and so on.
> >>
> >> Finally, rework default_suspend_ok() to explicitly handle the
> >> "no restriction" special case.
> >>
> >> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> >> ---
> 
> [cut]
> 
> > Looks good to me.
> >
> > Acked-by: Ramesh Thomas <ramesh.thomas@...el.com>
> 
> Thanks!
> 
> Do you actually mean Reviewed-by?

Yes, it should be Reveiewed-by for both patches!

Thanks,
Ramesh