Re: [PATCH v2] mm/codetag: swap tags when migrate pages

[David Wang]

At 2024-11-30 06:59:26, "Suren Baghdasaryan" <surenb@xxxxxxxxxx> wrote:
>On Thu, Nov 28, 2024 at 6:52 PM David Wang <00107082@xxxxxxx> wrote:
>>
>> Current solution to adjust codetag references during page migration is
>> done in 3 steps:
>> 1. sets the codetag reference of the old page as empty (not pointing
>> to any codetag);
>> 2. subtracts counters of the new page to compensate for its own allocation;
>> 3. sets codetag reference of the new page to point to the codetag of
>> the old page.
>> This does not work if CONFIG_MEM_ALLOC_PROFILING_DEBUG=n because
>> set_codetag_empty() becomes NOOP. Instead, let's simply swap codetag
>> references so that the new page is referencing the old codetag and the
>> old page is referencing the new codetag. This way accounting stays
>> valid and the logic makes more sense.
>>
>> Fixes: e0a955bf7f61 ("mm/codetag: add pgalloc_tag_copy()")
>> Signed-off-by: David Wang <00107082@xxxxxxx>
>> Closes: https://lore.kernel.org/lkml/20241124074318.399027-1-00107082@xxxxxxx/
>> Acked-by: Suren Baghdasaryan <surenb@xxxxxxxxxx>
>> Suggested-by: Suren Baghdasaryan <surenb@xxxxxxxxxx>
>
>Thanks! This looks fine to me but IIRC I did not Ack this patch

Sorry, I am kind of new to the kernel development process, still catching up. 

>before. In the future please do not add Acked-by until you get an
>explicit Ack. That said,

Roger that~
I was wondering when "Acked-by~ or "Rreviewd-by" were added in other commits. Now I understand,
I am not supposed to do that. 


Thanks
David

>