On 6/3/2022 2:34 PM, Aneesh Kumar K V wrote: > On 6/2/22 12:06 PM, Bharata B Rao wrote: >> On 6/1/2022 7:19 PM, Aneesh Kumar K V wrote: >>> On 6/1/22 11:59 AM, Bharata B Rao wrote: >>>> I was experimenting with this patchset and found this behaviour. >>>> Here's what I did: >>>> >>>> Boot a KVM guest with vNVDIMM device which ends up with device_dax >>>> driver by default. >>>> >>>> Use it as RAM by binding it to dax kmem driver. It now appears as >>>> RAM with a new NUMA node that is put to memtier1 (the existing tier >>>> where DRAM already exists) >>>> >>> >>> That should have placed it in memtier2. >>> >>>> I can move it to memtier2 (MEMORY_RANK_PMEM) manually, but isn't >>>> that expected to happen automatically when a node with dax kmem >>>> device comes up? >>>> >>> >>> This can happen if we have added the same NUMA node to memtier1 before dax kmem driver initialized the pmem memory. Can you check before the above node_set_memory_tier_rank() whether the specific NUMA node is already part of any memory tier? >> >> When we reach node_set_memory_tier_rank(), node1 (that has the pmem device) >> is already part of memtier1 whose nodelist shows 0-1. >> > > can you find out which code path added node1 to memtier1? node_set_memory_tier_rank+0x63/0x80 migrate_on_reclaim_callback+0x40/0x4d blocking_notifier_call_chain+0x68/0x90 memory_notify+0x1b/0x20 online_pages+0x257/0x2f0 memory_subsys_online+0x99/0x150 device_online+0x65/0x90 online_memory_block+0x1b/0x20 walk_memory_blocks+0x85/0xc0 ? generic_online_page+0x40/0x40 add_memory_resource+0x1fa/0x2d0 add_memory_driver_managed+0x80/0xc0 dev_dax_kmem_probe+0x1af/0x250 dax_bus_probe+0x6e/0xa0 After this the explicit call to node_set_memory_tier_rank(numa_node, MEMORY_RANK_PMEM) from dev_dax_kmem_probe() finds that the memtier is already set. > Do you have regular memory also appearing on node1? No, regular memory is on Node0. Regards, Bharata.
