>-----Original Message----- >From: owner-linux-mm@xxxxxxxxx [mailto:owner-linux-mm@xxxxxxxxx] On >Behalf Of Michal Hocko >Sent: Thursday, April 25, 2019 4:43 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 08:20:28, Du, Fan wrote: >> >> >> >-----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. > >I would still expect that a remote PMEM node access latency is >smaller/comparable to the real storage so a promoting part is not that >important for the unmapped pagecache. Maybe I am wrong here but that >really begs for some experiments before we start adding special casing. I understand your concern :), please refer to following summary from 3rd party. https://arxiv.org/pdf/1903.05714.pdf >-- >Michal Hocko >SUSE Labs
