From: Russ.Dill@ti•com (Russ Dill)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH RFC v1 3/3] ARM hibernation / suspend-to-disk
Date: Fri, 21 Feb 2014 22:46:59 -0800 [thread overview]
Message-ID: <530847E3.4070401@ti.com> (raw)
In-Reply-To: <20140222043714.19852.67450@capellas-linux>
On 02/21/2014 08:37 PM, Sebastian Capella wrote:
> Quoting Sebastian Capella (2014-02-21 15:59:11)
>> - Cyril Chemparathy as his email is bouncing back to me.
>>
>> Quoting Sebastian Capella (2014-02-21 10:39:56)
>>> Quoting Lorenzo Pieralisi (2014-02-20 08:27:55)
>>>>>>> + cpu_switch_mm(idmap_pgd, &init_mm);
>> [ ... ]
>>> I can try removing it and seeing if there are side effects.
>>
>> FYI, It's definitely hanging with this removed, still looking.
>
> I see when we reach this call, the 1st level page table @ TTBR0 is located
> at different memory locations each run (expected). If we omit the
> cpu_switch_mm we're corrupting the page table causing the observed
> intermittent failures. I believe these match the corruption you expected.
>
> The reason this doesn't happen when I leave the call is that idmap_pgd
> is always at the same memory location. I expect this is because it's
> allocated during init. I've seen the same address 50/50 times for
> idmap_pgd. I don't think it is correct to rely on this behavior.
>
> Would it be appropriate to use the swapper_pg_dir directly in place
> of idmap_pgd?
> - I do not see any modification to the swapper_pg_dir contents in the
> code that would change from init time.
> - swapper_pg_dir is always at the same offset.
>
> Ideally we should have no issue with overwriting it with identical data.
>
> I've run a couple hundred test loops using swapper_pg_dir and so far
> there are no failures.
If there is worry about this, you could setup a page mapping in a
__nosave region, preventing it from being overwritten.
next prev parent reply other threads:[~2014-02-22 6:46 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-19 1:52 [PATCH RFC v1 0/3] hibernation support on ARM Sebastian Capella
2014-02-19 1:52 ` [PATCH RFC v1 1/3] ARM: Add irq disabled version of soft_restart Sebastian Capella
2014-02-22 10:26 ` Russell King - ARM Linux
2014-02-24 23:13 ` Sebastian Capella
2014-02-25 0:22 ` Sebastian Capella
2014-02-25 7:56 ` Russ Dill
2014-02-25 10:27 ` Thomas Gleixner
2014-02-25 17:15 ` Russ Dill
2014-02-25 23:24 ` Sebastian Capella
2014-02-19 1:52 ` [PATCH RFC v1 2/3] Fix hibernation restore hang in freeze_processes Sebastian Capella
2014-02-24 7:09 ` Ming Lei
2014-02-19 1:52 ` [PATCH RFC v1 3/3] ARM hibernation / suspend-to-disk Sebastian Capella
2014-02-19 16:12 ` Lorenzo Pieralisi
2014-02-19 19:10 ` Russ Dill
2014-02-20 10:37 ` Lorenzo Pieralisi
2014-02-19 19:33 ` Sebastian Capella
2014-02-20 16:27 ` Lorenzo Pieralisi
2014-02-21 18:39 ` Sebastian Capella
2014-02-21 23:59 ` Sebastian Capella
2014-02-22 4:37 ` Sebastian Capella
2014-02-22 6:46 ` Russ Dill [this message]
2014-02-22 10:22 ` Russell King - ARM Linux
2014-02-22 10:16 ` Russell King - ARM Linux
2014-02-22 12:13 ` Lorenzo Pieralisi
2014-02-22 22:30 ` Pavel Machek
2014-02-21 1:01 ` Sebastian Capella
2014-02-22 10:38 ` Russell King - ARM Linux
2014-02-22 12:09 ` Lorenzo Pieralisi
2014-02-22 22:28 ` Pavel Machek
2014-02-23 19:52 ` Sebastian Capella
2014-02-23 20:02 ` Sebastian Capella
2014-02-25 11:32 ` Lorenzo Pieralisi
2014-02-25 17:55 ` Sebastian Capella
2014-02-26 10:24 ` Lorenzo Pieralisi
2014-02-26 17:50 ` Sebastian Capella
2014-02-26 19:03 ` Lorenzo Pieralisi
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