Re: [PATCH] mm: split thp synchronously on MADV_DONTNEED

[David Hildenbrand]

On 23.11.21 18:24, Shakeel Butt wrote:
> On Tue, Nov 23, 2021 at 9:20 AM David Hildenbrand <david@xxxxxxxxxx> wrote:
>>
>> On 23.11.21 18:17, Shakeel Butt wrote:
>>> On Tue, Nov 23, 2021 at 8:57 AM David Hildenbrand <david@xxxxxxxxxx> wrote:
>>>>
>>> [...]
>>>>>>
>>>>>> I do wonder which these locking contexts are exactly, and if we could
>>>>>> also do the same thing on ordinary munmap -- because I assume it can be
>>>>>> similarly problematic for some applications.
>>>>>
>>>>> This is a good question regarding munmap. One main difference is
>>>>> munmap takes mmap_lock in write mode and usually performance critical
>>>>> applications avoid such operations.
>>>>
>>>> Maybe we can extend it too most page zapping, if that makes things simpler.
>>>>
>>>
>>> Do you mean doing sync THP split for most of page zapping functions
>>> (but only if that makes things simpler)?
>>>
>>
>> Yes -- if there are no downsides.
>>
> 
> I will try. At the moment the assumption of "Not null zap_details
> implies leave swap entries" is giving me a headache.

Not only you, did you stumble over

https://lkml.kernel.org/r/20211115134951.85286-1-peterx@xxxxxxxxxx

already?

-- 
Thanks,

David / dhildenb