Re: [PATCH 00/10] use folio in ksm

Alex Shi
2024-06-05T03:46:29Z

On 6/4/24 9:28 PM, David Hildenbrand wrote:
> On 04.06.24 06:24, alexs@kernel.org wrote:
>> From: "Alex Shi (tencent)" <alexs@kernel.org>
>>
>> This is the 2nd part to use folio in ksm, it saves 82kbytes in ksm.o and
>> passed all ksm testcases in kselftest.
>>
>> KSM still split same folios to single page if they are good to be KSM,
>> but will skip the rest subpage checking if a folio couldn't suit for
>> ksm.
>>
>> Alex Shi (tencent) (10):
>>    mm/ksm: reduce the flush action for ksm merging page
>>    mm/ksm: skip subpages of compound pages
>>    mm/ksm: use folio in try_to_merge_one_page
>>    mm/ksm: add identical_folio func
>>    mm/ksm: use folio in stable_tree_search
>>    mm/ksm: remove page_stable_node
>>    mm/ksm: use folio in unstable_tree_search_insert
>>    mm/ksm: use folio in try_to_merge_xx serie funcs
>>    mm/ksm: calc_checksum for folio
>>    m/ksm: use folio in ksm scan path
>
> I skimmed over most patches, but I'm afraid you introduce quite some subtle problems.
>
> Part of the rework should not be do convert things to folios that really operate on pages (of possibly large folios).
>
> We really have to be careful about pages vs. folios before we have KSM folios. Only then, we know that we have small folios only.
>

Thanks a lot for your reviewing and comments. Let's if we'd do it better with your comments! :)

Thanks
Alex