linux-kernel - Re: drm/nouneau: 5.11 cycle regression bisected to 461619f5c324 "drm/nouveau: switch to new allocator"

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Date:   Wed, 10 Feb 2021 16:34:42 +0100
From:   Christian König <christian.koenig@....com>
To:     Mike Galbraith <efault@....de>, lkml <linux-kernel@...r.kernel.org>
Cc:     nouveau@...ts.freedesktop.org, Ben Skeggs <bskeggs@...hat.com>,
        Dave Airlie <airlied@...hat.com>
Subject: Re: drm/nouneau: 5.11 cycle regression bisected to 461619f5c324
 "drm/nouveau: switch to new allocator"



Am 10.02.21 um 16:30 schrieb Mike Galbraith:
> On Wed, 2021-02-10 at 14:26 +0100, Christian König wrote:
>> Am 10.02.21 um 13:22 schrieb Mike Galbraith:
>>> On Wed, 2021-02-10 at 12:44 +0100, Christian König wrote:
>>>> Please try to add a "return NULL" at the beginning of ttm_pool_type_take().
>>>>
>>>> That should effectively disable using the pool.
>>> That did away with the yield looping, but it doesn't take long for the
>>> display to freeze.  I ssh'd in from lappy, but there was nada in dmesg.
>> Yeah, that is expected. Without taking pages from the pool we leak
>> memory like sieve.
>>
>> At least we could narrow down the problem quite a bit with that.
>>
>> Can you test the attached patch and see if it helps?
> Yup, that seems to have fixed it all up.  Another one bites the dust ;)

Ah! So basically nouveau relies on that the pages are cleared.

Yeah, that wasn't consitently implemented before. Some code path was 
clearing the page, some wasn't.

Any objections that I add a Reported-and-tested-by: Mike Galbraith 
<efault@....de> ?

Regards,
Christian.

>
> 	-Mike
>