Re: [PATCH 0/3] mm, thp: remove duplication and fix locking issues in swapin

[Ebru Akagunduz]

On Mon, May 23, 2016 at 08:14:08PM +0300, Ebru Akagunduz wrote:
> This patch series removes duplication of included header
> and fixes locking inconsistency in khugepaged swapin
> 
> Ebru Akagunduz (3):
>   mm, thp: remove duplication of included header
>   mm, thp: fix possible circular locking dependency caused by
>     sum_vm_event()
>   mm, thp: make swapin readahead under down_read of mmap_sem
> 
>  mm/huge_memory.c | 39 ++++++++++++++++++++++++++++++---------
>  1 file changed, 30 insertions(+), 9 deletions(-)
> 

Hi Andrew,

I prepared this patch series to solve rest of
problems of khugepaged swapin.

I have seen the discussion:
http://marc.info/?l=linux-mm&m=146373278424897&w=2

In my opinion, checking whether kswapd is wake up
could be good.

It's up to you. I can take an action according to community's decision.

Here is the last status of the discussion:

"
Optimistic swapin collapsing

1. it could be too optimisitic to lose the gain due to evicting workingset
2. let's detect memory pressure
3. current allocstall magic is not a good idea.
4. let's change the design from optimistic to conservative
5. how we can be conservative
6. two things - detect hot pages and threshold of swap pte
7. threhsold of swap pte is already done so remained thing is detect hot page
8. how to detect hot page - let's use young bit
9. Now, we are conservatie so we will swap in when it's worth
10. let's remove allocstall magic

I think it's not off-topic.
Anyway, it's just my thought and don't have any real workload and objection.
Feel free to ignore.
"

Thanks.