RE: [RFC PATCH 5/5] mm, page_alloc: Introduce ZONELIST_FALLBACK_SAME_TYPE fallback list

[Du, Fan]

>-----Original Message-----
>From: owner-linux-mm@xxxxxxxxx [mailto:owner-linux-mm@xxxxxxxxx] On
>Behalf Of Michal Hocko
>Sent: Thursday, April 25, 2019 4:10 PM
>To: Du, Fan <fan.du@xxxxxxxxx>
>Cc: akpm@xxxxxxxxxxxxxxxxxxxx; Wu, Fengguang <fengguang.wu@xxxxxxxxx>;
>Williams, Dan J <dan.j.williams@xxxxxxxxx>; Hansen, Dave
><dave.hansen@xxxxxxxxx>; xishi.qiuxishi@xxxxxxxxxxxxxxx; Huang, Ying
><ying.huang@xxxxxxxxx>; linux-mm@xxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
>Subject: Re: [RFC PATCH 5/5] mm, page_alloc: Introduce
>ZONELIST_FALLBACK_SAME_TYPE fallback list
>
>On Thu 25-04-19 07:55:58, Du, Fan wrote:
>> >> PMEM is good for frequently read accessed page, e.g. page cache(implicit
>> >> page
>> >> request), or user space data base (explicit page request)
>> >> For now this patch create GFP_SAME_NODE_TYPE for such cases,
>additional
>> >> Implementation will be followed up.
>> >
>> >Then simply configure that NUMA node as movable and you get these
>> >allocations for any movable allocation. I am not really convinced a new
>> >gfp flag is really justified.
>>
>> Case 1: frequently write and/or read accessed page deserved to DRAM
>
>NUMA balancing

Sorry, I mean page cache case here.
Numa balancing works for pages mapped in pagetable style.

>> Case 2: frequently read accessed page deserved to PMEM
>
>memory reclaim to move those pages to a more distant node (e.g. a PMEM).
>
>Btw. none of the above is a static thing you would easily know at the
>allocation time.
>
>Please spare some time reading surrounding discussions - e.g.
>http://lkml.kernel.org/r/1554955019-29472-1-git-send-email-yang.shi@xxxxxxx
>libaba.com

Thanks for the point.

>Michal Hocko
>SUSE Labs