Re: [PATCH v4] mm/demotion: Expose memory tier details via sysfs
From: Huang, Ying
Date: Sun Sep 25 2022 - 21:04:41 EST
Aneesh Kumar K V <aneesh.kumar@xxxxxxxxxxxxx> writes:
> On 9/23/22 1:37 PM, Huang, Ying wrote:
>> "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxx> writes:
>>
>>> This patch adds /sys/devices/virtual/memory_tiering/ where all memory tier
>>> related details can be found. All allocated memory tiers will be listed
>>> there as /sys/devices/virtual/memory_tiering/memory_tierN/
>>>
>>> The nodes which are part of a specific memory tier can be listed via
>>> /sys/devices/virtual/memory_tiering/memory_tierN/nodes
>>
>> It appears that XXXs is used for mask while XXXs_list is used for list?
>> For example,
>>
>> # cat /sys/devices/system/cpu/cpu2/topology/core_cpus
>> 0,00100004
>> # cat /sys/devices/system/cpu/cpu2/topology/core_cpus_list
>> 2,20
>>
>> It's better to follow the this convention?
>>
>
> That is not followed in other parts of the kernel. I was loking at cpuset
>
> $cat cpuset.cpus.effective
> 0-7
Per my understanding, cpuset isn't sysfs, but cgroupfs?
I did some research in my system,
$ grep . $(find /sys/devices | grep 'list$')
and
$ grep . $(find /sys/devices | grep 'cpus$')
I found that the cpus/cpus_list convention is used in
- pci
/sys/devices/pci0000:64/0000:64:0d.2/local_cpulist:0-35
/sys/devices/pci0000:64/0000:64:0c.2/local_cpus:f,ffffffff
- system
/sys/devices/system/cpu/cpu7/topology/core_cpus_list:7,25
/sys/devices/system/cpu/cpu7/topology/core_cpus:0,02000080
- block
/sys/devices/virtual/block/loop1/mq/0/cpu_list:0, 1, 2, ...
- net
/sys/devices/virtual/net/lo/queues/rx-0/rps_cpus:0,00000000
And I haven't found any exception in sysfs of my system. Can you find
some?
Best Regards,
Huang, Ying
>>> A directory hierarchy looks like
>>> :/sys/devices/virtual/memory_tiering$ tree memory_tier4/
>>> memory_tier4/
>>> ├── nodes
>>> ├── subsystem -> ../../../../bus/memory_tiering
>>> └── uevent
>>>
>>> :/sys/devices/virtual/memory_tiering$ cat memory_tier4/nodes
>>> 0,2
>>>
>>> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx>
>>
>> Best Regards,
>> Huang, Ying
>>
>> [snip]