Hi Fan Awesome, thanks for the info!
On Fri, 11 Aug 2023 at 22:19, Fan Ni <fan...@gmx.us> wrote: > > On Fri, Aug 11, 2023 at 07:52:25AM +0530, Maverickk 78 wrote: > > Thanks Fan, > > > > cxl create-region works like a charm :) > > > > Since this gets listed as "System Ram(kmem)", I guess the kernel > > treats it as regular memory and > > allocates it to the applications when needed? > > or is there an extra effort needed to make it available for > > applications on the host? > > > > Yes. Once it is onlined, you can use it as regular memory. > CXL memory will serve as a zero-CPU memory-only NUMA node. > You can check it with numactl -H. > > To use the cxl memory with an app, you can use > numactl --membind=numa_id app_name > #numa_id is the dedicated numa node where cxl memory sits. > > One thing to notes, kvm will not work correctly with Qemu emulation when > you try to use cxl memory for an application, so do not enable kvm. > > Fan > > > On Thu, 10 Aug 2023 at 22:03, Fan Ni <fan...@gmx.us> wrote: > > > > > > On Wed, Aug 09, 2023 at 04:21:47AM +0530, Maverickk 78 wrote: > > > > Hello, > > > > > > > > I am running qemu-system-x86_64 > > > > > > > > qemu-system-x86_64 --version > > > > QEMU emulator version 8.0.92 (v8.1.0-rc2-80-g0450cf0897) > > > > > > > > qemu-system-x86_64 \ > > > > -m 2G,slots=4,maxmem=4G \ > > > > -smp 4 \ > > > > -machine type=q35,accel=kvm,cxl=on \ > > > > -enable-kvm \ > > > > -nographic \ > > > > -device pxb-cxl,id=cxl.0,bus=pcie.0,bus_nr=52 \ > > > > -device cxl-rp,id=rp0,bus=cxl.0,chassis=0,port=0,slot=0 \ > > > > -object > > > > memory-backend-file,id=mem0,mem-path=/tmp/mem0,size=1G,share=true \ > > > > -device cxl-type3,bus=rp0,volatile-memdev=mem0,id=cxl-mem0 \ > > > > -M cxl-fmw.0.targets.0=cxl.0,cxl-fmw.0.size=1G > > > > > > > > > > > > I was expecting the CXL memory to be listed in "System Ram", the lsmem > > > > shows only 2G memory which is System RAM, it's not listing the CXL > > > > memory. > > > > > > > > Do I need to pass any particular parameter in the kernel command line? > > > > > > > > Is there any documentation available? I followed the inputs provided in > > > > > > > > https://lore.kernel.org/linux-mm/y+csoehvlkudn...@kroah.com/T/ > > > > > > > > Is there any documentation/blog listed? > > > > > > If I remember it correctly, for volatile cxl memory, we need to create a > > > region and then it will be discovered as system memory and shows up. > > > > > > Try to create a region with "cxl create-region". > > > > > > Fan > > > >
