On Thu, Sep 19, 2019 at 08:10:47AM -0700, Dan Williams wrote: > On Thu, Sep 19, 2019 at 4:56 AM Adam Borowski <[email protected]> wrote: > > Hi! > > If I try to change the mode of a devdax namespace that's in use (mapped by > > some process), ndctl hangs: > > Is it merely mapped, or might the pages be actively pinned / in use by > another part of the kernel? The kernel has no choice but to wait for > active page pins to drain. Can you get a stack trace of the process > with the dev-dax instance mapped?
Looks like the behaviour is different depending on what the other process is: * with qemu, the hang is 100% reproducible, the guest continues to work and cleanly exits -- qemu does not exit on its own (unlike normal case) but SIGTERM terminates it correctly. Thus, qemu is not stuck, only ndctl is. * with mere mmap() (I've used vmemcache) ndctl allows reconfiguring the namespace. No hang. My way to start qemu is: .---- #!/bin/sh NET="-net bridge -net nic" DISK=eoan-devdax.disk exec qemu-system-x86_64 -enable-kvm -m 4096,slots=2,maxmem=16G -smp 8 $NET \ -drive if=none,id=hd,file="$DISK",format=raw,cache=unsafe,discard=on \ -device virtio-scsi-pci,id=scsi -device scsi-hd,drive=hd \ -M pc,nvdimm,nvdimm-persistence=mem-ctrl \ -object memory-backend-file,id=mem1,share=on,mem-path=/dev/dax0.0,size=4225761280,align=2M,pmem=on \ -device nvdimm,id=nvdimm1,memdev=mem1,label-size=256K \ -vnc :5 `---- Meow! -- ⢀⣴⠾⠻⢶⣦⠀ A MAP07 (Dead Simple) raspberry tincture recipe: 0.5l 95% alcohol, ⣾⠁⢠⠒⠀⣿⡁ 1kg raspberries, 0.4kg sugar; put into a big jar for 1 month. ⢿⡄⠘⠷⠚⠋⠀ Filter out and throw away the fruits (can dump them into a cake, ⠈⠳⣄⠀⠀⠀⠀ etc), let the drink age at least 3-6 months. _______________________________________________ Linux-nvdimm mailing list [email protected] https://lists.01.org/mailman/listinfo/linux-nvdimm
