Re: [PATCH] mm: thp: don't have to lock page anymore when splitting PMD

[David Hildenbrand]

On 08.03.22 00:43, Andrew Morton wrote:
> On Mon, 7 Mar 2022 09:24:58 +0100 David Hildenbrand <david@xxxxxxxxxx> wrote:
> 
>> On 07.03.22 03:07, Andrew Morton wrote:
>>> On Fri, 4 Mar 2022 19:50:08 +0100 David Hildenbrand <david@xxxxxxxxxx> wrote:
>>>
>>>> @Andrew, the last mail I received was
>>>>
>>>> + mm-huge_memory-remove-stale-locking-logic-from-__split_huge_pmd.patch
>>>> added to -mm tree
>>>>
>>>> The patch shows up in mmotm as
>>>>
>>>> #[merged]mm-huge_memory-remove-stale-locking-logic-from-__split_huge_pmd.patch
>>>>
>>>> ... which shouldn't be true.
>>>
>>> I guess I mislabelled the reason for dropping it.  Should have been to-be-updated, 
>>> due to https://lkml.kernel.org/r/CAHbLzkpbnQyHRckoRtbZoaLvANu92MY4kEsbKudaQ8MDUA3nVg@xxxxxxxxxxxxxx
>>>
>>
>> Let me clarify.
>>
>> 1. I sent [1] (9 patches)
>>
>> 2. You queued the 9 patches
>>
>> E.g., in "mmotm 2022-02-15-20-22 uploaded"
>>
>> * mm-optimize-do_wp_page-for-exclusive-pages-in-the-swapcache.patch
>> * mm-optimize-do_wp_page-for-fresh-pages-in-local-lru-pagevecs.patch
>> * mm-slightly-clarify-ksm-logic-in-do_swap_page.patch
>> * mm-streamline-cow-logic-in-do_swap_page.patch
>> * mm-huge_memory-streamline-cow-logic-in-do_huge_pmd_wp_page.patch
>> * mm-khugepaged-remove-reuse_swap_page-usage.patch
>> * mm-swapfile-remove-stale-reuse_swap_page.patch
>> * mm-huge_memory-remove-stale-page_trans_huge_mapcount.patch
>> * mm-huge_memory-remove-stale-locking-logic-from-__split_huge_pmd.patch
>>
>> 3. The last patch in the series was dropped. What remains are 8 patches.
>>
>> E.g., in "mmotm 2022-02-24-22-38 uploaded"
>>
>> * mm-optimize-do_wp_page-for-exclusive-pages-in-the-swapcache.patch
>> * mm-optimize-do_wp_page-for-fresh-pages-in-local-lru-pagevecs.patch
>> * mm-slightly-clarify-ksm-logic-in-do_swap_page.patch
>> * mm-streamline-cow-logic-in-do_swap_page.patch
>> * mm-huge_memory-streamline-cow-logic-in-do_huge_pmd_wp_page.patch
>> * mm-khugepaged-remove-reuse_swap_page-usage.patch
>> * mm-swapfile-remove-stale-reuse_swap_page.patch
>> * mm-huge_memory-remove-stale-page_trans_huge_mapcount.patch
>>
>> 4. Yang Shi sent his patch (the one we're replying to)
>>
>> 5. You picked his patch and dropped it again due to [2]
>>
>>
>> I'm wondering why 3 happened and why
>> https://www.ozlabs.org/~akpm/mmotm/series contains:
>>
>>
>> mm-optimize-do_wp_page-for-exclusive-pages-in-the-swapcache.patch
>> mm-optimize-do_wp_page-for-fresh-pages-in-local-lru-pagevecs.patch
>> mm-slightly-clarify-ksm-logic-in-do_swap_page.patch
>> mm-streamline-cow-logic-in-do_swap_page.patch
>> mm-huge_memory-streamline-cow-logic-in-do_huge_pmd_wp_page.patch
>> mm-khugepaged-remove-reuse_swap_page-usage.patch
>> mm-swapfile-remove-stale-reuse_swap_page.patch
>> mm-huge_memory-remove-stale-page_trans_huge_mapcount.patch
>> ...
>> #[merged]mm-huge_memory-remove-stale-locking-logic-from-__split_huge_pmd.patch
> 
> OK, thanks.  I guess it was me seeing 100% rejects when merging onto
> the folio changes then incorrectly deciding the patch was now in
> linux-next via some other tree.
> 

Thanks Andrew, my 2 cents would have been that my series, which fixes
actual CVEs should go in before folio cleanups. But that's a different
discussion (and the patch is question is just a cleanup part of the same
series, so i don't particularly care).

> I restored it and fixed things up.  Please check.
> 

That change looks good to me. I'd even say that we do the second cleanup
separately, with Yang Shi being the author. But whatever you+others prefer.


-- 
Thanks,

David / dhildenb