Re: PM regression in next

[Tony Lindgren <tony@atomide.com>]

* Andrew Morton <akpm@linux-foundation.org> [180112 00:45]:
> On Thu, 11 Jan 2018 16:23:22 -0800 Tony Lindgren <tony@atomide.com> wrote:
> 
> > * Andrew Morton <akpm@linux-foundation.org> [180112 00:18]:
> > > On Thu, 11 Jan 2018 16:01:13 -0800 Tony Lindgren <tony@atomide.com> wrote:
> > > 
> > > > Hi all,
> > > > 
> > > > I'm seeing a considerable idle power consumption regression in
> > > > Linux next, with power consumption for my idle test system going
> > > > to 17.5mW compared to the usual 8mW on my test device.
> > > > 
> > > > Git bisect points to merge commit e130bc1d00a4 ("Merge branch
> > > > 'akpm-current/current'") being the first bad commit.
> > > > 
> > > > I have also verified that commit 70286688e5ad ("ipc/mqueue.c:
> > > > have RT tasks queue in by priority in wq_add()") is good, and
> > > > commit e2d7fe89e8ae ("Merge remote-tracking branch
> > > > 'init_task/init_task'") is good.
> > > 
> > > Do you mean that everything up to and including 70286688e5ad
> > > ("ipc/mqueue.c: have RT tasks queue in by priority in wq_add()") is
> > > good?
> > 
> > Yes I'm not seeing the regression in your branch at commit
> > 70286688e5ad. I'm seeing it only with the merge commit
> > e130bc1d00a4.
> > 
> 
> That's weird.  All I'm seeing between 70286688e5ad and end-of-mm is:
> 
> tools-objtool-makefile-dont-assume-sync-checksh-is-executable.patch
> ipc-mqueue-add-missing-error-code-in-init_mqueue_fs.patch
> 
> vfs-remove-might_sleep-from-clear_inode.patch
> 
> mm-remove-duplicate-includes.patch
> 
> mm-remove-unneeded-kallsyms-include.patch
> hrtimer-remove-unneeded-kallsyms-include.patch
> genirq-remove-unneeded-kallsyms-include.patch
> 
> mm-memblock-memblock_is_map-region_memory-can-be-boolean.patch
> lib-lockref-__lockref_is_dead-can-be-boolean.patch
> kernel-cpuset-current_cpuset_is_being_rebound-can-be-boolean.patch
> kernel-resource-iomem_is_exclusive-can-be-boolean.patch
> kernel-module-module_is_live-can-be-boolean.patch
> kernel-mutex-mutex_is_locked-can-be-boolean.patch
> crash_dump-is_kdump_kernel-can-be-boolean.patch
> 
> fix-const-confusion-in-certs-blacklist.patch
> fix-read-buffer-overflow-in-delta-ipc.patch
> 
> kasan-rework-kconfig-settings.patch
> 
> sparc64-ng4-memset-32-bits-overflow.patch
> 
> lib-crc-ccitt-add-ccitt-false-crc16-variant.patch

Well there are some changes in merge commit e130bc1d00a4..

> And I don't see how any of those can cause this.  Did anything else
> change, like context switch rates, interrupt rates, etc?

Well I tried to measure suspend power consumption and noticed
that system suspend fails too hand hangs the network device:

# echo mem > /sys/power/state
[   32.577850] PM: suspend entry (deep)
[   32.582031] PM: Syncing filesystems ... done.
[   32.598083] Freezing user space processes ... (elapsed 0.002 seconds) done.
[   32.608398] OOM killer disabled.
[   32.611846] Freezing remaining freezable tasks ... (elapsed 0.002 seconds) done.
[   32.622192] Suspending console(s) (use no_console_suspend to debug)
[   32.651123] dpm_run_callback(): mdio_bus_suspend+0x0/0x24 returns 4352
[   32.651428] PM: Device 2c000000.ethernet-ffffffff:01 failed to suspend: error 4352
[   32.653289] PM: Some devices failed to suspend, or early wake event detected
[   32.685455] OOM killer enabled.
[   32.688629] Restarting tasks ... done.
[   32.695983] PM: suspend exit
ash: write error: Bad address

That too works just fine at commit 70286688e5ad.

Regards,

Tony