Messages in this thread Patch in this message | | | From | "Huang, Ying" <> | Subject | Re: [PATCH -V10 RESEND 0/6] NUMA balancing: optimize memory placement for memory tiering system | Date | Thu, 13 Jan 2022 20:06:40 +0800 |
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Peter Zijlstra <peterz@infradead.org> writes:
> On Thu, Jan 13, 2022 at 03:19:06PM +0800, Huang, Ying wrote: >> Hi, Peter, >> >> Peter Zijlstra <peterz@infradead.org> writes: >> >> > On Tue, Dec 07, 2021 at 10:27:51AM +0800, Huang Ying wrote: >> >> After commit c221c0b0308f ("device-dax: "Hotplug" persistent memory >> >> for use like normal RAM"), the PMEM could be used as the >> >> cost-effective volatile memory in separate NUMA nodes. In a typical >> >> memory tiering system, there are CPUs, DRAM and PMEM in each physical >> >> NUMA node. The CPUs and the DRAM will be put in one logical node, >> >> while the PMEM will be put in another (faked) logical node. >> > >> > So what does a system like that actually look like, SLIT table wise, and >> > how does that affect init_numa_topology_type() ? >> >> The SLIT table is as follows, >> >> [000h 0000 4] Signature : "SLIT" [System Locality Information Table] >> [004h 0004 4] Table Length : 0000042C >> [008h 0008 1] Revision : 01 >> [009h 0009 1] Checksum : 59 >> [00Ah 0010 6] Oem ID : "INTEL " >> [010h 0016 8] Oem Table ID : "S2600WF " >> [018h 0024 4] Oem Revision : 00000001 >> [01Ch 0028 4] Asl Compiler ID : "INTL" >> [020h 0032 4] Asl Compiler Revision : 20091013 >> >> [024h 0036 8] Localities : 0000000000000004 >> [02Ch 0044 4] Locality 0 : 0A 15 11 1C >> [030h 0048 4] Locality 1 : 15 0A 1C 11 >> [034h 0052 4] Locality 2 : 11 1C 0A 1C >> [038h 0056 4] Locality 3 : 1C 11 1C 0A >> >> The `numactl -H` output is as follows, >> >> available: 4 nodes (0-3) >> node 0 cpus: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 >> node 0 size: 64136 MB >> node 0 free: 5981 MB >> node 1 cpus: 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 >> node 1 size: 64466 MB >> node 1 free: 10415 MB >> node 2 cpus: >> node 2 size: 253952 MB >> node 2 free: 253920 MB >> node 3 cpus: >> node 3 size: 253952 MB >> node 3 free: 253951 MB >> node distances: >> node 0 1 2 3 >> 0: 10 21 17 28 >> 1: 21 10 28 17 >> 2: 17 28 10 28 >> 3: 28 17 28 10 >> >> init_numa_topology_type() set sched_numa_topology_type to NUMA_DIRECT. >> >> The node 0 and node 1 are onlined during boot. While the PMEM node, >> that is, node 2 and node 3 are onlined later. As in the following dmesg >> snippet. > > But how? sched_init_numa() scans the *whole* SLIT table to determine > nr_levels / sched_domains_numa_levels, even offline nodes. Therefore it > should find 4 distinct distance values and end up not selecting > NUMA_DIRECT. > > Similarly for the other types it uses for_each_online_node(), which > would include the pmem nodes once they've been onlined, but I'm thinking > we explicitly want to skip CPU-less nodes in that iteration.
I used the debug patch as below, and get the log in dmesg as follows,
[ 5.394577][ T1] sched_numa_topology_type: 0, levels: 4, max_distance: 28
I found that I forget another caller of init_numa_topology_type() run during hotplug. I will add another printk() to show it. Sorry about that.
Best Regards, Huang, Ying
-------------------------------8<------------------------------------ From 11cea4be2db6220333d84f5b168174f534ac0933 Mon Sep 17 00:00:00 2001 From: Huang Ying <ying.huang@intel.com> Date: Thu, 13 Jan 2022 09:53:15 +0800 Subject: [PATCH] dbg: show sched_numa_topology_type
--- kernel/sched/topology.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c index d201a7052a29..9d92191fd62d 100644 --- a/kernel/sched/topology.c +++ b/kernel/sched/topology.c @@ -1914,6 +1914,10 @@ void sched_init_numa(void) init_numa_topology_type(); + pr_info("sched_numa_topology_type: %d, levels: %d, max_distance: %d\n", + sched_numa_topology_type, sched_domains_numa_levels, + sched_max_numa_distance); + sched_numa_onlined_nodes = bitmap_alloc(nr_node_ids, GFP_KERNEL); if (!sched_numa_onlined_nodes) return; -- 2.30.2
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