Re: [fake numa not working] [PATCH 1/1] mm/fake-numa: allow later numa node hotplug

Hyeonggon Yoo
2025-01-20T04:35:39Z

On 1/20/2025 12:27 PM, Zi Yan wrote:
> On Sun Jan 19, 2025 at 9:37 PM EST, Hyeonggon Yoo wrote:
>>
>>
>> On 1/20/2025 11:16 AM, Zi Yan wrote:
>>> On Sun Jan 19, 2025 at 7:37 PM EST, Hyeonggon Yoo wrote:
>>>>
>>>>
>>>> On 1/18/2025 4:09 AM, Zi Yan wrote:
>>>>> On 17 Jan 2025, at 0:00, Hyeonggon Yoo wrote:
>>>>>
>>>>>> On 1/6/2025 9:06 PM, Bruno Faccini wrote:
>>>>>>> Current fake-numa implementation prevents new Numa
>>>>>>> nodes to be later hot-plugged by drivers.
>>>>>>> A common symptom of this limitation is the
>>>>>>> "node <X> was absent from the node_possible_map"
>>>>>>> message by associated warning in mm/memory_hotplug.c:
>>>>>>> add_memory_resource().
>>>>>>> This comes from the lack of remapping in both
>>>>>>> pxm_to_node_map[] and node_to_pxm_map[] tables
>>>>>>> to take fake-numa nodes into account and thus
>>>>>>> triggers collisions with original and physical nodes
>>>>>>> only-mapping that had been determined from BIOS tables.
>>>>>>> This patch fixes this by doing the necessary node-ids
>>>>>>> translation in both pxm_to_node_map[]/node_to_pxm_map[]
>>>>>>> tables.
>>>>>>> node_distance[] table has also been fixed accordingly.
>>>>>>>
>>>>>>> Signed-off-by: Bruno Faccini <bfaccini@nvidia.com>
>>>>>>
>>>>>> Hi Bruno,
>>>>>>
>>>>>> This commit causes WARN() and disables fakenuma
>>>>>> when I pass "numa=fake=4U" on my QEMU setup.
>>>>>>
>>>>>> Attaching WARN() log and git bisect log to help debugging.
>>>>>
>>>>> Is your VM getting 4 NUMA nodes at the end?
>>>>
>>>> No, it only gets node 0 at the end.
>>>
>>> Got it.
>>>
>>>>
>>>>> Can you also share your QEMU command line and your kernel config?
>>>>
>>>> The config is attached (fakenuma.config)
>>>>
>>>> QEMU command line:
>>>> $ qemu-system-x86_64 \
>>>> -cpu host \
>>>> -enable-kvm \
>>>> -smp $(nproc) \
>>>> -m 32G \
>>>> -nographic \
>>>> -kernel arch/x86/boot/bzImage \
>>>> -initrd ../../rootfs.cpio.gz \
>>>> -nic user,model=virtio-net-pci \
>>>> -append "console=ttyS0 numa=fake=4U"
>>>>
>>>>> This can help Bruno reproduce the issue locally. At least, I
>>>>> cannot reproduce it on mm-everything-2025-01-16-23-18.
>>>>
>>>> Still reproduced on mm-everything-2025-01-18-04-55 with my setup.
>>>>
>>>>> I also
>>>>> notice that my VM does not have “No NUMA configuration found”
>>>>> (in your log) in its kernel log and that might explain
>>>>> why I could not reproduce it.
>>>>
>>>> Did you do NUMA configuration (-numa in QEMU) for your VM?
>>>> I didn't, but it's still expected to work 'cause it's fake numa.
>>>
>>> No. It seems that the "No NUMA configuration found" is caused by your
>>> qemu, where dummy_numa_init() is used (maybe ACPI SRAT is not
>>> populated?)
>>
>> FYI, Yes. ACPI SRAT is not populated.
>>
>> $ qemu-system-x86_64 --version
>> QEMU emulator version 6.2.0 (Debian 1:6.2+dfsg-2ubuntu6.24)
>> Copyright (c) 2003-2021 Fabrice Bellard and the QEMU Project developers
>
> Basically, fix_pxm_node_maps() breaks fakenuma when it cannot fix the
> pxm_to_node_map() due to ACPI SRAT is missing. IMHO, it should let
> fakenuma proceed with a warning. The diff below fixed the issue
> locally, but Bruno can tell if I miss anything.
>
> diff --git a/drivers/acpi/numa/srat.c b/drivers/acpi/numa/srat.c
> index 59fffe34c9d0..18d04f054e93 100644
> --- a/drivers/acpi/numa/srat.c
> +++ b/drivers/acpi/numa/srat.c
> @@ -95,9 +95,12 @@ int __init fix_pxm_node_maps(int max_nid)
> int i, j, index = -1, count = 0;
> nodemask_t nodes_to_enable;
>
> - if (numa_off || srat_disabled())
> + if (numa_off)
> return -1;
>
> + if (srat_disabled())
> + return 0;
> +
> /* find fake nodes PXM mapping */
> for (i = 0; i < MAX_NUMNODES; i++) {
> if (node_to_pxm_map[i] != PXM_INVAL) {
> @@ -117,9 +120,9 @@ int __init fix_pxm_node_maps(int max_nid)
> }
> }
> }
> - if (WARN(index != max_nid, "%d max nid when expected %d\n",
> - index, max_nid))
> - return -1;
> + /* No srat data */
> + if (index != max_nid)
> + return 0;
>
> nodes_clear(nodes_to_enable);

Thanks, this fixes the bug on my environment as well.

>>
>>> I used the patch below to emulate the situation and
>>> reproduced the issue. Since dummy_numa_init() is used when there is
>>> no underlying NUMA architecture, NUMA initialization fails, or NUMA
>>> is disabled on the command line (the last does not apply here),
>>> it should be properly handled. I will let Bruno look into it.
>>>
>>> Thank you for the info.
>>>
>>> diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c
>>> index 64e5cdb2460a..70dfd9bfb23f 100644
>>> --- a/arch/x86/mm/numa.c
>>> +++ b/arch/x86/mm/numa.c
>>> @@ -223,7 +223,7 @@ static int __init dummy_numa_init(void)
>>> */
>>> void __init x86_numa_init(void)
>>> {
>>> - if (!numa_off) {
>>> + if (0 && !numa_off) {
>>> #ifdef CONFIG_ACPI_NUMA
>>> if (!numa_init(x86_acpi_numa_init))
>>> return;
>>>
>>>>>>
>>>>>> [WARN() splat]
>>>>>>
>>>>>> [ 0.009676] No NUMA configuration found
>>>>>> [ 0.009677] Faking a node at [mem 0x0000000000000000-0x000000083fffffff]
>>>>>> [ 0.009705] Fake node size 16895MB too small, increasing to 16896MB
>>>>>> [ 0.009708] Faking node 0 at [mem 0x0000000000001000-0x0000000420000fff] (16896MB)
>>>>>> [ 0.009711] Faking node 1 at [mem 0x0000000420001000-0x000000083fffffff] (16895MB)
>>>>>> [ 0.009738] ------------[ cut here ]------------
>>>>>> [ 0.009739] -1 max nid when expected 1
>>>>>> [ 0.009760] WARNING: CPU: 0 PID: 0 at drivers/acpi/numa/srat.c:120 fix_pxm_node_maps+0x577/0x810
>>>>>> [ 0.009766] Modules linked in:
>>>>>> [ 0.009769] CPU: 0 UID: 0 PID: 0 Comm: swapper Not tainted 6.13.0-rc6+ #31
>>>>>> [ 0.009771] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
>>>>>> [ 0.009772] RIP: 0010:fix_pxm_node_maps+0x577/0x810
>>>>>> [ 0.009774] Code: 8b 85 40 ff ff ff 44 8b 8d 44 ff ff ff 8b 85 48 ff ff ff e9 83 fb ff ff 44 89 f2 44 89 ce 48 c7 c7 aa 2f 84 8d e8 b9 71 01 fe <0f> 0b 41 b8 ff ff ff ff e9 ba fb ff ff 48 c7 c7 a0 d8 d1 8d 44 89
>>>>>> [ 0.009776] RSP: 0000:ffffffff8da03be0 EFLAGS: 00010046 ORIG_RAX: 0000000000000000
>>>>>> [ 0.009778] RAX: 0000000000000000 RBX: 0000000000000400 RCX: 0000000000000000
>>>>>> [ 0.009779] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
>>>>>> [ 0.009780] RBP: ffffffff8da03ca8 R08: 0000000000000000 R09: 0000000000000000
>>>>>> [ 0.009781] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001
>>>>>> [ 0.009782] R13: 00000000000007ff R14: 0000000000000001 R15: 0000000000000000
>>>>>> [ 0.009783] FS: 0000000000000000(0000) GS:ffffffff8de8c000(0000) knlGS:0000000000000000
>>>>>> [ 0.009784] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>>>>>> [ 0.009785] CR2: ffff90e4bde01000 CR3: 00000001bd03e000 CR4: 00000000000200b0
>>>>>> [ 0.009788] Call Trace:
>>>>>> [ 0.009790] <TASK>
>>>>>> [ 0.009792] ? show_regs+0x71/0x90
>>>>>> [ 0.009797] ? __warn+0x8d/0x150
>>>>>> [ 0.009799] ? fix_pxm_node_maps+0x577/0x810
>>>>>> [ 0.009802] ? report_bug+0x1ab/0x1c0
>>>>>> [ 0.009805] ? fixup_exception+0x27/0x380
>>>>>> [ 0.009809] ? early_fixup_exception+0xa2/0xf0
>>>>>> [ 0.009813] ? do_early_exception+0x28/0x90
>>>>>> [ 0.009816] ? early_idt_handler_common+0x2f/0x3a
>>>>>> [ 0.009819] ? fix_pxm_node_maps+0x577/0x810
>>>>>> [ 0.009822] ? numa_cleanup_meminfo+0x8c/0x5b0
>>>>>> [ 0.009828] numa_emulation+0x4e3/0xad0
>>>>>> [ 0.009830] ? __pfx_dummy_numa_init+0x10/0x10
>>>>>> [ 0.009833] ? __pfx_dummy_numa_init+0x10/0x10
>>>>>> [ 0.009836] numa_memblks_init+0x10c/0x2c0
>>>>>> [ 0.009838] ? __pfx_dummy_numa_init+0x10/0x10
>>>>>> [ 0.009840] numa_init+0x61/0x3e0
>>>>>> [ 0.009842] ? topology_register_boot_apic+0x2a/0x40
>>>>>> [ 0.009846] x86_numa_init+0x65/0x80
>>>>>> [ 0.009848] initmem_init+0xe/0x20
>>>>>> [ 0.009850] setup_arch+0x9d8/0xfa0
>>>>>> [ 0.009852] ? _printk+0x58/0x90
>>>>>> [ 0.009855] start_kernel+0x5f/0xb50
>>>>>> [ 0.009860] x86_64_start_reservations+0x18/0x30
>>>>>> [ 0.009863] x86_64_start_kernel+0xc0/0x110
>>>>>> [ 0.009864] ? setup_ghcb+0xe/0x140
>>>>>> [ 0.009867] common_startup_64+0x13e/0x141
>>>>>> [ 0.009871] </TASK>
>>>>>> [ 0.009871] ---[ end trace 0000000000000000 ]---
>>>>>>
>>>>>> [Git bisect log]
>>>>>>
>>>>>> # bad: [f378252a2168c2fbf8fc08b635061e5f6748c1f2] kasan: sw_tags: use str_on_off() helper in kasan_init_sw_tags()
>>>>>> git bisect bad f378252a2168c2fbf8fc08b635061e5f6748c1f2
>>>>>> # good: [cbc5dde0a461240046e8a41c43d7c3b76d5db952] fs/proc: fix softlockup in __read_vmcore (part 2)
>>>>>> git bisect good cbc5dde0a461240046e8a41c43d7c3b76d5db952
>>>>>> # good: [fb73203263021f2ee9dd54d280b1c543d10acd76] mm: move common part of pagetable_*_ctor to helper
>>>>>> git bisect good fb73203263021f2ee9dd54d280b1c543d10acd76
>>>>>> # bad: [8fd966c9310f14d5bbe653cf087853582170aad6] mm, swap: remove old allocation path for HDD
>>>>>> git bisect bad 8fd966c9310f14d5bbe653cf087853582170aad6
>>>>>> # bad: [8646971f02651146554233d63fdd721f5f060973] mm: shmem: skip swapcache for swapin of synchronous swap device
>>>>>> git bisect bad 8646971f02651146554233d63fdd721f5f060973
>>>>>> # good: [b8ba614eaa8dd31702c61e7df7231b1b18b99259] mm/damon/paddr: report filter-passed bytes back for DAMOS_STAT action
>>>>>> git bisect good b8ba614eaa8dd31702c61e7df7231b1b18b99259
>>>>>> # good: [fd0935b8e9e8c2edf05a3d0ffa09d0aa3e9cf2dd] Docs/ABI/damon: document per-region DAMOS filter-passed bytes stat file
>>>>>> git bisect good fd0935b8e9e8c2edf05a3d0ffa09d0aa3e9cf2dd
>>>>>> # good: [3ffd3cd7e2e8793d3b5fbb83c03668c47ab6d599] selftests/damon: remove tests for DAMON debugfs interface
>>>>>> git bisect good 3ffd3cd7e2e8793d3b5fbb83c03668c47ab6d599
>>>>>> # good: [bf9f93f0b7bff8af780330f5094775a39caf3612] mm/damon: remove DAMON debugfs interface
>>>>>> git bisect good bf9f93f0b7bff8af780330f5094775a39caf3612
>>>>>> # bad: [1746744be6ff271e29345a5be4cc144aa33b10ab] mm/memmap: prevent double scanning of memmap by kmemleak
>>>>>> git bisect bad 1746744be6ff271e29345a5be4cc144aa33b10ab
>>>>>> # bad: [ca19a5ab8756ef78c34d02d2b8c266a9cc7bf57d] mm/fake-numa: allow later numa node hotplug
>>>>>> git bisect bad ca19a5ab8756ef78c34d02d2b8c266a9cc7bf57d
>>>>>> # first bad commit: [ca19a5ab8756ef78c34d02d2b8c266a9cc7bf57d] mm/fake-numa: allow later numa node hotplug
>>>>>>
>>>>>>> ---
>>>>>>> drivers/acpi/numa/srat.c | 86 ++++++++++++++++++++++++++++++++++++
>>>>>>> include/acpi/acpi_numa.h | 5 +++
>>>>>>> include/linux/numa_memblks.h | 3 ++
>>>>>>> mm/numa_emulation.c | 45 ++++++++++++++++---
>>>>>>> mm/numa_memblks.c | 2 +-
>>>>>>> 5 files changed, 133 insertions(+), 8 deletions(-)
>>>>>>>
>>>>>>> diff --git a/drivers/acpi/numa/srat.c b/drivers/acpi/numa/srat.c
>>>>>>> index bec0dcd1f9c3..59fffe34c9d0 100644
>>>>>>> --- a/drivers/acpi/numa/srat.c
>>>>>>> +++ b/drivers/acpi/numa/srat.c
>>>>>>> @@ -81,6 +81,92 @@ int acpi_map_pxm_to_node(int pxm)
>>>>>>> }
>>>>>>> EXPORT_SYMBOL(acpi_map_pxm_to_node);
>>>>>>> +#ifdef CONFIG_NUMA_EMU
>>>>>>> +/*
>>>>>>> + * Take max_nid - 1 fake-numa nodes into account in both
>>>>>>> + * pxm_to_node_map()/node_to_pxm_map[] tables.
>>>>>>> + */
>>>>>>> +int __init fix_pxm_node_maps(int max_nid)
>>>>>>> +{
>>>>>>> + static int pxm_to_node_map_copy[MAX_PXM_DOMAINS] __initdata
>>>>>>> + = { [0 ... MAX_PXM_DOMAINS - 1] = NUMA_NO_NODE };
>>>>>>> + static int node_to_pxm_map_copy[MAX_NUMNODES] __initdata
>>>>>>> + = { [0 ... MAX_NUMNODES - 1] = PXM_INVAL };
>>>>>>> + int i, j, index = -1, count = 0;
>>>>>>> + nodemask_t nodes_to_enable;
>>>>>>> +
>>>>>>> + if (numa_off || srat_disabled())
>>>>>>> + return -1;
>>>>>>> +
>>>>>>> + /* find fake nodes PXM mapping */
>>>>>>> + for (i = 0; i < MAX_NUMNODES; i++) {
>>>>>>> + if (node_to_pxm_map[i] != PXM_INVAL) {
>>>>>>> + for (j = 0; j <= max_nid; j++) {
>>>>>>> + if ((emu_nid_to_phys[j] == i) &&
>>>>>>> + WARN(node_to_pxm_map_copy[j] != PXM_INVAL,
>>>>>>> + "Node %d is already binded to PXM %d\n",
>>>>>>> + j, node_to_pxm_map_copy[j]))
>>>>>>> + return -1;
>>>>>>> + if (emu_nid_to_phys[j] == i) {
>>>>>>> + node_to_pxm_map_copy[j] =
>>>>>>> + node_to_pxm_map[i];
>>>>>>> + if (j > index)
>>>>>>> + index = j;
>>>>>>> + count++;
>>>>>>> + }
>>>>>>> + }
>>>>>>> + }
>>>>>>> + }
>>>>>>> + if (WARN(index != max_nid, "%d max nid when expected %d\n",
>>>>>>> + index, max_nid))
>>>>>>> + return -1;
>>>>>>> +
>>>>>>> + nodes_clear(nodes_to_enable);
>>>>>>> +
>>>>>>> + /* map phys nodes not used for fake nodes */
>>>>>>> + for (i = 0; i < MAX_NUMNODES; i++) {
>>>>>>> + if (node_to_pxm_map[i] != PXM_INVAL) {
>>>>>>> + for (j = 0; j <= max_nid; j++)
>>>>>>> + if (emu_nid_to_phys[j] == i)
>>>>>>> + break;
>>>>>>> + /* fake nodes PXM mapping has been done */
>>>>>>> + if (j <= max_nid)
>>>>>>> + continue;
>>>>>>> + /* find first hole */
>>>>>>> + for (j = 0;
>>>>>>> + j < MAX_NUMNODES &&
>>>>>>> + node_to_pxm_map_copy[j] != PXM_INVAL;
>>>>>>> + j++)
>>>>>>> + ;
>>>>>>> + if (WARN(j == MAX_NUMNODES,
>>>>>>> + "Number of nodes exceeds MAX_NUMNODES\n"))
>>>>>>> + return -1;
>>>>>>> + node_to_pxm_map_copy[j] = node_to_pxm_map[i];
>>>>>>> + node_set(j, nodes_to_enable);
>>>>>>> + count++;
>>>>>>> + }
>>>>>>> + }
>>>>>>> +
>>>>>>> + /* creating reverse mapping in pxm_to_node_map[] */
>>>>>>> + for (i = 0; i < MAX_NUMNODES; i++)
>>>>>>> + if (node_to_pxm_map_copy[i] != PXM_INVAL &&
>>>>>>> + pxm_to_node_map_copy[node_to_pxm_map_copy[i]] == NUMA_NO_NODE)
>>>>>>> + pxm_to_node_map_copy[node_to_pxm_map_copy[i]] = i;
>>>>>>> +
>>>>>>> + /* overwrite with new mapping */
>>>>>>> + for (i = 0; i < MAX_NUMNODES; i++) {
>>>>>>> + node_to_pxm_map[i] = node_to_pxm_map_copy[i];
>>>>>>> + pxm_to_node_map[i] = pxm_to_node_map_copy[i];
>>>>>>> + }
>>>>>>> +
>>>>>>> + /* enable other nodes found in PXM for hotplug */
>>>>>>> + nodes_or(numa_nodes_parsed, nodes_to_enable, numa_nodes_parsed);
>>>>>>> +
>>>>>>> + pr_debug("found %d total number of nodes\n", count);
>>>>>>> + return 0;
>>>>>>> +}
>>>>>>> +#endif
>>>>>>> +
>>>>>>> static void __init
>>>>>>> acpi_table_print_srat_entry(struct acpi_subtable_header *header)
>>>>>>> {
>>>>>>> diff --git a/include/acpi/acpi_numa.h b/include/acpi/acpi_numa.h
>>>>>>> index b5f594754a9e..99b960bd473c 100644
>>>>>>> --- a/include/acpi/acpi_numa.h
>>>>>>> +++ b/include/acpi/acpi_numa.h
>>>>>>> @@ -17,11 +17,16 @@ extern int node_to_pxm(int);
>>>>>>> extern int acpi_map_pxm_to_node(int);
>>>>>>> extern unsigned char acpi_srat_revision;
>>>>>>> extern void disable_srat(void);
>>>>>>> +extern int fix_pxm_node_maps(int max_nid);
>>>>>>> extern void bad_srat(void);
>>>>>>> extern int srat_disabled(void);
>>>>>>> #else /* CONFIG_ACPI_NUMA */
>>>>>>> +static inline int fix_pxm_node_maps(int max_nid)
>>>>>>> +{
>>>>>>> + return 0;
>>>>>>> +}
>>>>>>> static inline void disable_srat(void)
>>>>>>> {
>>>>>>> }
>>>>>>> diff --git a/include/linux/numa_memblks.h b/include/linux/numa_memblks.h
>>>>>>> index cfad6ce7e1bd..dd85613cdd86 100644
>>>>>>> --- a/include/linux/numa_memblks.h
>>>>>>> +++ b/include/linux/numa_memblks.h
>>>>>>> @@ -29,7 +29,10 @@ int __init numa_cleanup_meminfo(struct numa_meminfo *mi);
>>>>>>> int __init numa_memblks_init(int (*init_func)(void),
>>>>>>> bool memblock_force_top_down);
>>>>>>> +extern int numa_distance_cnt;
>>>>>>> +
>>>>>>> #ifdef CONFIG_NUMA_EMU
>>>>>>> +extern int emu_nid_to_phys[MAX_NUMNODES];
>>>>>>> int numa_emu_cmdline(char *str);
>>>>>>> void __init numa_emu_update_cpu_to_node(int *emu_nid_to_phys,
>>>>>>> unsigned int nr_emu_nids);
>>>>>>> diff --git a/mm/numa_emulation.c b/mm/numa_emulation.c
>>>>>>> index 031fb9961bf7..9d55679d99ce 100644
>>>>>>> --- a/mm/numa_emulation.c
>>>>>>> +++ b/mm/numa_emulation.c
>>>>>>> @@ -8,11 +8,12 @@
>>>>>>> #include <linux/memblock.h>
>>>>>>> #include <linux/numa_memblks.h>
>>>>>>> #include <asm/numa.h>
>>>>>>> +#include <acpi/acpi_numa.h>
>>>>>>> #define FAKE_NODE_MIN_SIZE ((u64)32 << 20)
>>>>>>> #define FAKE_NODE_MIN_HASH_MASK (~(FAKE_NODE_MIN_SIZE - 1UL))
>>>>>>> -static int emu_nid_to_phys[MAX_NUMNODES];
>>>>>>> +int emu_nid_to_phys[MAX_NUMNODES];
>>>>>>> static char *emu_cmdline __initdata;
>>>>>>> int __init numa_emu_cmdline(char *str)
>>>>>>> @@ -379,6 +380,7 @@ void __init numa_emulation(struct numa_meminfo *numa_meminfo, int numa_dist_cnt)
>>>>>>> size_t phys_size = numa_dist_cnt * numa_dist_cnt * sizeof(phys_dist[0]);
>>>>>>> int max_emu_nid, dfl_phys_nid;
>>>>>>> int i, j, ret;
>>>>>>> + nodemask_t physnode_mask = numa_nodes_parsed;
>>>>>>> if (!emu_cmdline)
>>>>>>> goto no_emu;
>>>>>>> @@ -395,7 +397,6 @@ void __init numa_emulation(struct numa_meminfo *numa_meminfo, int numa_dist_cnt)
>>>>>>> * split the system RAM into N fake nodes.
>>>>>>> */
>>>>>>> if (strchr(emu_cmdline, 'U')) {
>>>>>>> - nodemask_t physnode_mask = numa_nodes_parsed;
>>>>>>> unsigned long n;
>>>>>>> int nid = 0;
>>>>>>> @@ -465,9 +466,6 @@ void __init numa_emulation(struct numa_meminfo *numa_meminfo, int numa_dist_cnt)
>>>>>>> */
>>>>>>> max_emu_nid = setup_emu2phys_nid(&dfl_phys_nid);
>>>>>>> - /* commit */
>>>>>>> - *numa_meminfo = ei;
>>>>>>> -
>>>>>>> /* Make sure numa_nodes_parsed only contains emulated nodes */
>>>>>>> nodes_clear(numa_nodes_parsed);
>>>>>>> for (i = 0; i < ARRAY_SIZE(ei.blk); i++)
>>>>>>> @@ -475,10 +473,21 @@ void __init numa_emulation(struct numa_meminfo *numa_meminfo, int numa_dist_cnt)
>>>>>>> ei.blk[i].nid != NUMA_NO_NODE)
>>>>>>> node_set(ei.blk[i].nid, numa_nodes_parsed);
>>>>>>> - numa_emu_update_cpu_to_node(emu_nid_to_phys, ARRAY_SIZE(emu_nid_to_phys));
>>>>>>> + /* fix pxm_to_node_map[] and node_to_pxm_map[] to avoid collision
>>>>>>> + * with faked numa nodes, particularly during later memory hotplug
>>>>>>> + * handling, and also update numa_nodes_parsed accordingly.
>>>>>>> + */
>>>>>>> + ret = fix_pxm_node_maps(max_emu_nid);
>>>>>>> + if (ret < 0)
>>>>>>> + goto no_emu;
>>>>>>> +
>>>>>>> + /* commit */
>>>>>>> + *numa_meminfo = ei;
>>>>>>> +
>>>>>>> + numa_emu_update_cpu_to_node(emu_nid_to_phys, max_emu_nid + 1);
>>>>>>> /* make sure all emulated nodes are mapped to a physical node */
>>>>>>> - for (i = 0; i < ARRAY_SIZE(emu_nid_to_phys); i++)
>>>>>>> + for (i = 0; i < max_emu_nid + 1; i++)
>>>>>>> if (emu_nid_to_phys[i] == NUMA_NO_NODE)
>>>>>>> emu_nid_to_phys[i] = dfl_phys_nid;
>>>>>>> @@ -501,12 +510,34 @@ void __init numa_emulation(struct numa_meminfo *numa_meminfo, int numa_dist_cnt)
>>>>>>> numa_set_distance(i, j, dist);
>>>>>>> }
>>>>>>> }
>>>>>>> + for (i = 0; i < numa_distance_cnt; i++) {
>>>>>>> + for (j = 0; j < numa_distance_cnt; j++) {
>>>>>>> + int physi, physj;
>>>>>>> + u8 dist;
>>>>>>> +
>>>>>>> + /* distance between fake nodes is already ok */
>>>>>>> + if (emu_nid_to_phys[i] != NUMA_NO_NODE &&
>>>>>>> + emu_nid_to_phys[j] != NUMA_NO_NODE)
>>>>>>> + continue;
>>>>>>> + if (emu_nid_to_phys[i] != NUMA_NO_NODE)
>>>>>>> + physi = emu_nid_to_phys[i];
>>>>>>> + else
>>>>>>> + physi = i - max_emu_nid;
>>>>>>> + if (emu_nid_to_phys[j] != NUMA_NO_NODE)
>>>>>>> + physj = emu_nid_to_phys[j];
>>>>>>> + else
>>>>>>> + physj = j - max_emu_nid;
>>>>>>> + dist = phys_dist[physi * numa_dist_cnt + physj];
>>>>>>> + numa_set_distance(i, j, dist);
>>>>>>> + }
>>>>>>> + }
>>>>>>> /* free the copied physical distance table */
>>>>>>> memblock_free(phys_dist, phys_size);
>>>>>>> return;
>>>>>>> no_emu:
>>>>>>> + numa_nodes_parsed = physnode_mask;
>>>>>>> /* No emulation. Build identity emu_nid_to_phys[] for numa_add_cpu() */
>>>>>>> for (i = 0; i < ARRAY_SIZE(emu_nid_to_phys); i++)
>>>>>>> emu_nid_to_phys[i] = i;
>>>>>>> diff --git a/mm/numa_memblks.c b/mm/numa_memblks.c
>>>>>>> index a3877e9bc878..ff4054f4334d 100644
>>>>>>> --- a/mm/numa_memblks.c
>>>>>>> +++ b/mm/numa_memblks.c
>>>>>>> @@ -7,7 +7,7 @@
>>>>>>> #include <linux/numa.h>
>>>>>>> #include <linux/numa_memblks.h>
>>>>>>> -static int numa_distance_cnt;
>>>>>>> +int numa_distance_cnt;
>>>>>>> static u8 *numa_distance;
>>>>>>> nodemask_t numa_nodes_parsed __initdata;
>>>>>
>>>>>
>>>>> Best Regards,
>>>>> Yan, Zi
>>>>>
>>>
>>>
>>>
>>>
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