From: Will Deacon <will.deacon@arm.com>
To: Kevin Hilman <khilman@linaro.org>
Cc: Catalin Marinas <Catalin.Marinas@arm.com>,
"larry.bassel@linaro.org \"linux-kernel@vger.kernel.org\""
<linux-kernel@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linaro-kernel@lists.linaro.org" <linaro-kernel@lists.linaro.org>
Subject: Re: [PATCH v6 2/2] arm64: enable context tracking
Date: Tue, 3 Jun 2014 11:26:46 +0100 [thread overview]
Message-ID: <20140603102646.GB23149@arm.com> (raw)
In-Reply-To: <7hioonythl.fsf@paris.lan>
Hi guys,
On Fri, May 30, 2014 at 08:08:38PM +0100, Kevin Hilman wrote:
> Will Deacon <will.deacon@arm.com> writes:
> > I'd like to give these some stress testing before it gets merged, so I'm
> > not sure if it'll make it for 3.16 given where we are at the moment.
>
> FWIW, this feature is disabled by default. I use the following kconfig
> fragment to enable the various parts I use for testing:
>
> CONFIG_NO_HZ=y
> CONFIG_NO_HZ_FULL=y
> CONFIG_NO_HZ_FULL_ALL=y
> CONFIG_NO_HZ_FULL_SYSIDLE=y
>
> # default to power-efficient workqueues (which are then set to unbound)
> CONFIG_WQ_POWER_EFFICIENT_DEFAULT=y
>
> # lockup detector sets a 4s timer on every CPU, which wakes CPUs
> # from idle. (alternately, can be controlled via procfs,
> # e.g: echo 0 > /proc/sys/kernel/watchdog)
> #CONFIG_LOCKUP_DETECTOR=n
I had a go with this, but I couldn't seem to trigger any context tracking
without forcing CONFIG_CONTEXT_TRACKING_FORCE=y. Does that mean we're
missing something else?
Anyway, with that forced on, I see the following during boot:
------------[ cut here ]------------
WARNING: CPU: 0 PID: 0 at kernel/rcu/tree.c:418 rcu_eqs_enter+0x84/0xa4()
Modules linked in:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.15.0-rc8+ #5
Call trace:
[<ffffffc000088048>] dump_backtrace+0x0/0x130
[<ffffffc000088188>] show_stack+0x10/0x1c
[<ffffffc0004891a0>] dump_stack+0x74/0xbc
[<ffffffc0000a45e0>] warn_slowpath_common+0x8c/0xb4
[<ffffffc0000a46cc>] warn_slowpath_null+0x14/0x20
[<ffffffc0000efc14>] rcu_eqs_enter+0x80/0xa4
[<ffffffc0000efc58>] rcu_idle_enter+0x20/0x50
[<ffffffc0000dd314>] cpu_startup_entry+0x118/0x184
[<ffffffc0004865ec>] rest_init+0x7c/0x88
[<ffffffc000609800>] start_kernel+0x368/0x37c
---[ end trace c17313e162496e65 ]---
------------[ cut here ]------------
WARNING: CPU: 0 PID: 0 at kernel/rcu/tree.c:541 rcu_eqs_exit+0xb0/0xbc()
Modules linked in:
CPU: 0 PID: 0 Comm: swapper/0 Tainted: G W 3.15.0-rc8+ #5
Call trace:
[<ffffffc000088048>] dump_backtrace+0x0/0x130
[<ffffffc000088188>] show_stack+0x10/0x1c
[<ffffffc0004891a0>] dump_stack+0x74/0xbc
[<ffffffc0000a45e0>] warn_slowpath_common+0x8c/0xb4
[<ffffffc0000a46cc>] warn_slowpath_null+0x14/0x20
[<ffffffc0000ed384>] rcu_eqs_exit+0xac/0xbc
[<ffffffc0000efdac>] rcu_user_exit+0xc/0x18
[<ffffffc00011d48c>] context_tracking_user_exit+0xc4/0xd4
[<ffffffc000083d98>] el1_irq+0x58/0xd4
[<ffffffc0000dd318>] cpu_startup_entry+0x11c/0x184
[<ffffffc0004865ec>] rest_init+0x7c/0x88
[<ffffffc000609800>] start_kernel+0x368/0x37c
---[ end trace c17313e162496e66 ]---
Can you take a look please? I had to fix up some conflicts to apply your
patches against our for-next branch, so I've put a branch here for you to
look at:
git://git.kernel.org/pub/scm/linux/kernel/git/will/linux.git aarch64/context-tracking
Cheers,
Will
next prev parent reply other threads:[~2014-06-03 10:27 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-29 21:45 [PATCH v6 0/2] context tracker support for arm64 Larry Bassel
2014-05-29 21:45 ` [PATCH v6 1/2] arm64: adjust el0_sync so that a function can be called Larry Bassel
2014-05-30 18:20 ` Will Deacon
2014-05-29 21:45 ` [PATCH v6 2/2] arm64: enable context tracking Larry Bassel
2014-05-30 18:23 ` Will Deacon
[not found] ` <7hioonythl.fsf@paris.lan>
2014-06-03 10:26 ` Will Deacon [this message]
2014-06-03 17:34 ` Kevin Hilman
-- strict thread matches above, loose matches on Subject: below --
2014-05-29 20:08 [PATCH v6 0/2] context tracker support for arm64 Larry Bassel
2014-05-29 20:08 ` [PATCH v6 2/2] arm64: enable context tracking Larry Bassel
2014-05-29 20:37 ` Kevin Hilman
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