On Thu, Sep 1, 2022 at 11:44 PM Aneesh Kumar K V <aneesh.kumar@xxxxxxxxxxxxx> wrote: > > On 9/2/22 12:10 PM, Huang, Ying wrote: > > Aneesh Kumar K V <aneesh.kumar@xxxxxxxxxxxxx> writes: > > > >> On 9/2/22 11:42 AM, Huang, Ying wrote: > >>> Aneesh Kumar K V <aneesh.kumar@xxxxxxxxxxxxx> writes: > >>> > >>>> On 9/2/22 11:10 AM, Huang, Ying wrote: > >>>>> Aneesh Kumar K V <aneesh.kumar@xxxxxxxxxxxxx> writes: > >>>>> > >>>>>> On 9/2/22 10:39 AM, Wei Xu wrote: > >>>>>>> On Thu, Sep 1, 2022 at 5:33 PM Huang, Ying <ying.huang@xxxxxxxxx> wrote: > >>>>>>>> > >>>>>>>> Aneesh Kumar K V <aneesh.kumar@xxxxxxxxxxxxx> writes: > >>>>>>>> > >>>>>>>>> On 9/1/22 12:31 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 > >>>>>>>>>> > >>>>>>>>>> I think "memory_tier" is a better subsystem/bus name than > >>>>>>>>>> memory_tiering. Because we have a set of memory_tierN devices inside. > >>>>>>>>>> "memory_tier" sounds more natural. I know this is subjective, just my > >>>>>>>>>> preference. > >>>>>>>>>> > >>>>>> > >>>>>> > >>>>>> I missed replying to this earlier. I will keep memory_tiering as subsystem name in v4 > >>>>>> because we would want it to a susbsystem where all memory tiering related details can be found > >>>>>> including memory type in the future. This is as per discussion > >>>>>> > >>>>>> https://lore.kernel.org/linux-mm/CAAPL-u9TKbHGztAF=r-io3gkX7gorUunS2UfstudCWuihrA=0g@xxxxxxxxxxxxxx > >>>>> > >>>>> I don't think that it's a good idea to mix 2 types of devices in one > >>>>> subsystem (bus). If my understanding were correct, that breaks the > >>>>> driver core convention. > >>>>> > >>>> > >>>> All these are virtual devices .I am not sure i follow what you mean by 2 types of devices. > >>>> memory_tiering is a subsystem that represents all the details w.r.t memory tiering. It shows > >>>> details of memory tiers and can possibly contain details of different memory types . > >>> > >>> IMHO, memory_tier and memory_type are 2 kind of devices. They have > >>> almost totally different attributes (sysfs file). So, we should create > >>> 2 buses for them. Each has its own attribute group. "virtual" itself > >>> isn't a subsystem. > >> > >> Considering both the details are related to memory tiering, wouldn't it be much simpler we consolidate > >> them within the same subdirectory? I am still not clear why you are suggesting they need to be in different > >> sysfs hierarchy. It doesn't break any driver core convention as you mentioned earlier. > >> > >> /sys/devices/virtual/memory_tiering/memory_tierN > >> /sys/devices/virtual/memory_tiering/memory_typeN > > > > I think we should add > > > > /sys/devices/virtual/memory_tier/memory_tierN > > /sys/devices/virtual/memory_type/memory_typeN > > > > I am trying to find if there is a technical reason to do the same? > > > I don't think this is complex. Devices of same bus/subsystem should > > have mostly same attributes. This is my understanding of driver core > > convention. > > > > I was not looking at this from code complexity point. Instead of having multiple directories > with details w.r.t memory tiering, I was looking at consolidating the details > within the directory /sys/devices/virtual/memory_tiering. (similar to all virtual devices > are consolidated within /sys/devics/virtual/). > > -aneesh Here is an example of /sys/bus/nd/devices (I know it is not under /sys/devices/virtual, but it can still serve as a reference): ls -1 /sys/bus/nd/devices namespace2.0 namespace3.0 ndbus0 nmem0 nmem1 region0 region1 region2 region3 So I think it is not unreasonable if we want to group memory tiering related interfaces within a single top directory. Wei
