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For example, a Power system with 255 GB RAM failed to boot with the following kernel command-line arguments: default_hugepagesz=2M hugepagesz=2M hugepages=128512 The failure occurred with the following logs:   Booting a command list OF stdout device is: /vdevice/vty@30000000 Preparing to boot Linux version 6.19.0-rc1+ (root@root) (gcc (GCC), GNU ld version 2.35.2-63.el9) #4 SMP Thu Dec 18 09:02:16 CST 2025 Detected machine type: 0000000000000101 command line: BOOT_IMAGE=(ieee1275//vdevice/v-scsi@30000065/disk@8100000000000000,msdos2)/vmlinuz-6.19.0-rc1+ root=/dev/mapper/r-root ro rd.lvm.lv=root/root rd.lvm.lv=root/swap biosdevname=0 loglevel=7 ignore_loglevel debug console=hvc0 earlycon=hvc0 earlyprintk crashkernel=4G default_hugepagesz=2M hugepagesz=2M hugepages=128512 Max number of cores passed to firmware: 256 (NR_CPUS = 2048) Calling ibm,client-architecture-support... done memory layout at init:   memory_limit : 0000000000000000 (16 MB aligned)   alloc_bottom : 0000000016050000   alloc_top    : 0000000030000000   alloc_top_hi : 0000000030000000   rmo_top      : 0000000030000000   ram_top      : 0000000030000000 instantiating rtas at 0x000000002ec50000... done prom_hold_cpus: skipped copying OF device tree... Building dt strings... Building dt structure... Device tree strings 0x0000000016060000 -> 0x0000000016061844 Device tree struct  0x0000000016070000 -> 0x0000000016080000 Quiescing Open Firmware ... Booting Linux via __start() @ 0x000000000a700000 ... [    0.000000] printk: debug: ignoring loglevel setting. [    0.000000] crashkernel reserved: 0x0000000018000000 - 0x0000000118000000 (4096 MB) [    0.000000] radix-mmu: Page sizes from device-tree: [    0.000000] radix-mmu: Page size shift = 12 AP=0x0 [    0.000000] radix-mmu: Page size shift = 16 AP=0x5 [    0.000000] radix-mmu: Page size shift = 21 AP=0x1 [    0.000000] radix-mmu: Page size shift = 30 AP=0x2 [    0.000000] Activating Kernel Userspace Access Prevention [    0.000000] Activating Kernel Userspace Execution Prevention [    0.000000] radix-mmu: Mapped 0x0000000000000000-0x0000000002800000 with 2.00 MiB pages (exec) [    0.000000] radix-mmu: Mapped 0x0000000002800000-0x0000003ffde00000 with 2.00 MiB pages [    0.000000] radix-mmu: Mapped 0x0000003ffde00000-0x0000003ffdff0000 with 64.0 KiB pages [    0.000000] radix-mmu: Mapped 0x0000003fffff0000-0x0000004000000000 with 64.0 KiB pages [    0.000000] radix-mmu: Mapped 0x0000003ffdff0000-0x0000003fffff0000 with 64.0 KiB pages [    0.000000] lpar: Using radix MMU under hypervisor [    0.000000] Linux version 6.19.0-rc1+ (root) (gcc (GCC) GNU ld version 2.35.2-63.el9) #4 SMP Thu Dec 18 09:02:16 CST 202 5 [    0.000000] OF: reserved mem: Reserved memory: No reserved-memory node in the DT [    0.000000] Found initrd at 0xc00000000f800000:0xc000000016046afe [    0.000000] Hardware name: hv:phyp pSeries [    0.000000] printk: legacy bootconsole [udbg0] enabled [    0.000000] Partition configured for 72 cpus. [    0.000000] CPU maps initialized for 8 threads per core [    0.000000]  (thread shift is 3) [    0.000000] Initmem setup node 28 as memoryless [    0.000000] Initmem setup node 29 as memoryless [    0.000000] Initmem setup node 30 as memoryless [    0.000000] Initmem setup node 31 as memoryless [    0.000000] percpu: Embedded 3 pages/cpu s126488 r0 d70120 u196608 [    0.000000] pcpu-alloc: s126488 r0 d70120 u196608 alloc=3*65536 [    0.000000] pcpu-alloc: [0] 00 [0] 01 [0] 02 [0] 03 [0] 04 [0] 05 [0] 06 [0] 07 [    0.000000] pcpu-alloc: [0] 08 [0] 09 [0] 10 [0] 11 [0] 12 [0] 13 [0] 14 [0] 15 [    0.000000] pcpu-alloc: [0] 16 [0] 17 [0] 18 [0] 19 [0] 20 [0] 21 [0] 22 [0] 23 [    0.000000] pcpu-alloc: [0] 24 [0] 25 [0] 26 [0] 27 [0] 28 [0] 29 [0] 30 [0] 31 [    0.000000] pcpu-alloc: [1] 32 [1] 33 [1] 34 [1] 35 [1] 36 [1] 37 [1] 38 [1] 39 [    0.000000] pcpu-alloc: [1] 40 [1] 41 [1] 42 [1] 43 [1] 44 [1] 45 [1] 46 [1] 47 [    0.000000] pcpu-alloc: [1] 48 [1] 49 [1] 50 [1] 51 [1] 52 [1] 53 [1] 54 [1] 55 [    0.000000] pcpu-alloc: [1] 56 [1] 57 [1] 58 [1] 59 [1] 60 [1] 61 [1] 62 [1] 63 [    0.000000] pcpu-alloc: [2] 64 [2] 65 [2] 66 [2] 67 [2] 68 [2] 69 [2] 70 [2] 71 [    0.000000] Kernel command line: BOOT_IMAGE=(ieee1275//vdevice/v-scsi@30000065/disk@8100000000000000,msdos2)/vmlinuz-6.19.0-rc1+ root=/dev/mapper/root ro rd.lvm.lv=root/root rd.lvm.lv=root/swap biosdevname=0 loglevel=7 ignore_loglevel debug console=hvc0 earlycon=hvc0 earlyprintk crashkernel=4G default_hugepagesz=2M hugepagesz= 2M hugepages=128512 [    0.000000] Unknown kernel command line parameters "earlyprintk biosdevname=0", will be passed to user space. [    0.000000] random: crng init done [    0.000000] printk: log buffer data + meta data: 1048576 + 3670016 = 4718592 bytes [    0.070655] thermal_sys: Registered thermal governor 'step_wise' [    0.070709] cpuidle: using governor menu [    0.070781] RTAS daemon started [    0.070984] pstore: Using crash dump compression: deflate [    0.070988] pstore: Registered nvram as persistent store backend [    0.071386] EEH: pSeries platform initialized [    0.071459] plpks: POWER LPAR Platform KeyStore is not supported or enabled [    0.081865] kprobes: kprobe jump-optimization is enabled. All kprobes are optimized if possible. [    2.828787] HugeTLB: allocation took 2740ms with hugepage_allocation_threads=18 [    2.828821] HugeTLB: allocating 128512 of page size 2.00 MiB failed.  Only allocated 128429 hugepages. [    2.828852] HugeTLB: registered 2.00 MiB page size, pre-allocated 128429 pages [    2.828855] HugeTLB: 0 KiB vmemmap can be freed for a 2.00 MiB page [    2.828858] HugeTLB: registered 1.00 GiB page size, pre-allocated 0 pages [    2.828862] HugeTLB: 0 KiB vmemmap can be freed for a 1.00 GiB page [    2.831713] swapper/0: page allocation failure: order:5, mode:0xcc0(GFP_KERNEL), nodemask=(null),cpuset=/,mems_allowed=1-3 [    2.831732] CPU: 51 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.19.0-rc1+ #4 VOLUNTARY [    2.831736] Hardware name: hv:phyp pSeries [    2.831738] Call Trace: [    2.831738] [c000001c801b77c0] [c00000000111ae6c] dump_stack_lvl+0x8c/0xf0 (unreliable) [    2.831747] [c000001c801b77f0] [c00000000059a024] warn_alloc+0x12c/0x1d8 [    2.831752] [c000001c801b7890] [c00000000059a918] __alloc_pages_slowpath.constprop.0+0x848/0xa98 [    2.831755] [c000001c801b79d0] [c00000000059ae3c] __alloc_frozen_pages_noprof+0x2d4/0x3a8 [    2.831758] [c000001c801b7a50] [c0000000005eac64] alloc_pages_mpol+0x10c/0x1f4 [    2.831761] [c000001c801b7ab0] [c0000000005eadac] alloc_pages_noprof+0x60/0xe8 [    2.831763] [c000001c801b7ad0] [c0000000004d9978] mempool_alloc_pages+0x24/0x38 [    2.831767] [c000001c801b7af0] [c0000000004da4a0] mempool_init_node+0x138/0x1fc [    2.831769] [c000001c801b7b40] [c00000000208844c] bio_integrity_initfn+0x40/0x70 [    2.831773] [c000001c801b7ba0] [c000000000010c44] do_one_initcall+0x60/0x36c [    2.831776] [c000001c801b7c80] [c000000002006b2c] do_initcalls+0x12c/0x22c [    2.831779] [c000001c801b7d30] [c000000002006f1c] kernel_init_freeable+0x23c/0x390 [    2.831781] [c000001c801b7de0] [c000000000011078] kernel_init+0x34/0x26c [    2.831783] [c000001c801b7e50] [c00000000000dd3c] ret_from_kernel_user_thread+0x14/0x1c [    2.831786] ---- interrupt: 0 at 0x0 [    2.831790] Mem-Info: [    2.831871] active_anon:0 inactive_anon:0 isolated_anon:0 [    2.831871]  active_file:0 inactive_file:0 isolated_file:0 [    2.831871]  unevictable:0 dirty:0 writeback:0 [    2.831871]  slab_reclaimable:82 slab_unreclaimable:2106 [    2.831871]  mapped:0 shmem:0 pagetables:146 [    2.831871]  sec_pagetables:0 bounce:0 [    2.831871]  kernel_misc_reclaimable:0 [    2.831871]  free:944 free_pcp:3099 free_cma:0 [    2.831903] Node 1 active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB isolated(file):0kB mapped:0kB dirty:0kB writeback:0kB shmem:0kB sh mem_thp:0kB shmem_pmdmapped:0kB anon_thp:0kB kernel_stack:8000kB pagetables:4224kB sec_pagetables:0kB all_unreclaimable? no Balloon:0kB [    2.831925] Node 2 active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB isolated(file):0kB mapped:0kB dirty:0kB writeback:0kB shmem:0kB sh mem_thp:0kB shmem_pmdmapped:0kB anon_thp:0kB kernel_stack:7968kB pagetables:4096kB sec_pagetables:0kB all_unreclaimable? no Balloon:0kB [    2.831937] Node 3 active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB isolated(file):0kB mapped:0kB dirty:0kB writeback:0kB shmem:0kB sh mem_thp:0kB shmem_pmdmapped:0kB anon_thp:0kB kernel_stack:2272kB pagetables:1024kB sec_pagetables:0kB all_unreclaimable? no Balloon:0kB [    2.831962] Node 1 Normal free:19520kB boost:0kB min:29440kB low:144448kB high:259456kB reserved_highatomic:0KB free_highatomic:0KB active_anon:0kB inactive_anon:0kB active_file:0kB inacti ve_file:0kB unevictable:0kB writepending:0kB zspages:0kB present:119537664kB managed:115056960kB mlocked:0kB bounce:0kB free_pcp:84992kB local_pcp:2048kB free_cma:0kB [    2.831991] lowmem_reserve[]: 0 0 0 [    2.831997] Node 2 Normal free:39424kB boost:2048kB min:32512kB low:151360kB high:270208kB reserved_highatomic:0KB free_highatomic:0KB active_anon:0kB inactive_anon:0kB active_file:0kB ina ctive_file:0kB unevictable:0kB writepending:0kB zspages:0kB present:119013376kB managed:118885632kB mlocked:0kB bounce:0kB free_pcp:95552kB local_pcp:2816kB free_cma:0kB [    2.832008] lowmem_reserve[]: 0 0 0 [    2.832011] Node 3 Normal free:1472kB boost:0kB min:7616kB low:37376kB high:67136kB reserved_highatomic:0KB free_highatomic:0KB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_f ile:0kB unevictable:0kB writepending:0kB zspages:0kB present:29884416kB managed:29784448kB mlocked:0kB bounce:0kB free_pcp:17792kB local_pcp:0kB free_cma:0kB [    2.832021] lowmem_reserve[]: 0 0 0 [    2.832025] Node 1 Normal: 3*64kB (UME) 3*128kB (ME) 4*256kB (UME) 3*512kB (UME) 4*1024kB (ME) 0*2048kB 0*4096kB 0*8192kB 0*16384kB = 7232kB [    2.832037] Node 2 Normal: 1*64kB (U) 0*128kB 1*256kB (M) 0*512kB 2*1024kB (UM) 0*2048kB 0*4096kB 0*8192kB 0*16384kB = 2368kB [    2.832052] Node 3 Normal: 1*64kB (E) 1*128kB (M) 3*256kB (UME) 1*512kB (U) 0*1024kB 0*2048kB 0*4096kB 0*8192kB 0*16384kB = 1472kB [    2.832068] Node 1 hugepages_total=56043 hugepages_free=56043 hugepages_surp=0 hugepages_size=2048kB [    2.832078] Node 1 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=1048576kB [    2.832086] Node 2 hugepages_total=57915 hugepages_free=57915 hugepages_surp=0 hugepages_size=2048kB [    2.832093] Node 2 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=1048576kB [    2.832102] Node 3 hugepages_total=14471 hugepages_free=14471 hugepages_surp=0 hugepages_size=2048kB [    2.832111] Node 3 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=1048576kB [    2.832119] 0 total pagecache pages [    2.832122] 0 pages in swap cache [    2.832127] Free swap  = 0kB [    2.832130] Total swap = 0kB [    2.832133] 4194304 pages RAM [    2.832138] 0 pages HighMem/MovableOnly [    2.832141] 73569 pages reserved [    2.832143] 0 pages cma reserved [    2.832146] 0 pages hwpoisoned [    2.832153] Memory cgroup min protection 0kB -- low protection 0kB [    2.832154] Kernel panic - not syncing: bio: can't create integrity buf pool [    2.832160] CPU: 51 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.19.0-rc1+ #4 VOLUNTARY [    2.832164] Hardware name: hv:phyp pSeries [    2.832167] Call Trace: [    2.832169] [c000001c801b7a50] [c00000000111aeb8] dump_stack_lvl+0xd8/0xf0 (unreliable) [    2.832180] [c000001c801b7a80] [c00000000015d79c] vpanic+0x2c8/0x4b4 [    2.832189] [c000001c801b7b20] [c00000000015d9c8] nmi_panic+0x0/0xa0 [    2.832197] [c000001c801b7b40] [c000000002088478] bio_integrity_initfn+0x6c/0x70 [    2.832205] [c000001c801b7ba0] [c000000000010c44] do_one_initcall+0x60/0x36c [    2.832213] [c000001c801b7c80] [c000000002006b2c] do_initcalls+0x12c/0x22c [    2.832221] [c000001c801b7d30] [c000000002006f1c] kernel_init_freeable+0x23c/0x390 [    2.832229] [c000001c801b7de0] [c000000000011078] kernel_init+0x34/0x26c [    2.832237] [c000001c801b7e50] [c00000000000dd3c] ret_from_kernel_user_thread+0x14/0x1c [    2.832247] ---- interrupt: 0 at 0x0 [    2.834181] pstore: backend (nvram) writing error (-1) [    2.835809] Rebooting in 10 seconds.. I agree that reserving hugepages equal to the system RAM is not very practical. However, would it be a good idea to make the hugepage memory allocator aware of the total system memory and leave some memory for the kernel to boot? Thanks, Sourabh Jain