On Mon, 2022-05-30 at 13:50 +0100, Jonathan Cameron wrote: > On Sun, 29 May 2022 12:31:30 +0800 > Ying Huang <ying.huang@xxxxxxxxx> wrote: > > > On Fri, 2022-05-27 at 09:30 -0700, Wei Xu wrote: > > > On Fri, May 27, 2022 at 6:41 AM Aneesh Kumar K V > > > <aneesh.kumar@xxxxxxxxxxxxx> wrote: > > > > > > > > On 5/27/22 2:52 AM, Wei Xu wrote: > > > > > > > > > > > > > > > > > > > > > The order of memory tiers is determined by their rank values, not by > > > > > their memtier device names. > > > > > > > > > > - /sys/devices/system/memtier/possible > > > > > > > > > > Format: ordered list of "memtier(rank)" > > > > > Example: 0(64), 1(128), 2(192) > > > > > > > > > > Read-only. When read, list all available memory tiers and their > > > > > associated ranks, ordered by the rank values (from the highest > > > > > tier to the lowest tier). > > > > > > > > > > > > > > > > > > > > > > > > > > > > Did we discuss the need for this? I haven't done this in the patch > > > > series I sent across. > > > > > > The "possible" file is only needed if we decide to hide the > > > directories of memtiers that have no nodes. We can remove this > > > interface and always show all memtier directories to keep things > > > simpler. > > > > When discussed offline, Tim Chen pointed out that with the proposed > > interface, it's unconvenient to know the position of a given memory tier > > in all memory tiers. We must sort "rank" of all memory tiers to know > > that. "possible" file can be used for that. Although "possible" file > > can be generated with a shell script, it's more convenient to show it > > directly. > > > > Another way to address the issue is to add memtierN/pos for each memory > > tier as suggested by Tim. It's readonly and will show position of > > "memtierN" in all memory tiers. It's even better to show the relative > > postion to the default memory tier (DRAM with CPU). That is, the > > position of DRAM memory tier is 0. > > > > Unlike memory tier device ID or rank, the position is relative and > > dynamic. > > Hi, > > I'm unconvinced. This is better done with a shell script than > by adding ABI we'll have to live with for ever.. > > I'm no good at shell scripting but this does the job > grep "" tier*/rank | sort -n -k 2 -t : > > tier2/rank:50 > tier0/rank:100 > tier1/rank:200 > tier3/rank:240 > > I'm sure someone more knowledgeable will do it in a simpler fashion still. I am OK to leave this to be added later if we found that it's useful. Best Regards, Huang, Ying > Jonathan > > > > > Best Regards, > > Huang, Ying > > > > >
