512MB（x86）システムでは82MBの「予約メモリ」
512MBの古いx86システムに新しいDebian 10を再インストールしましたRAM（すべて正常に動作します）。
使用可能なメモリは431MBです。 （現在接続されているグラフィックカードはありません）
古い3.xカーネルではそれほど多くのメモリが「予約」されていないと思います
$ free -m
total used free shared buff/cache available
Mem: 431 59 311 4 60 355
$ cat /proc/meminfo
MemTotal: 441568 kB
ログには、メモリに関する多くの情報が含まれていますが、何が関連しているかはわかりません。私は失われたRAMがどこに行くのか知りたいだけです。
編集：dmesg全体
[ 0.000000] Linux version 4.19.0-5-686-pae ([email protected]) (gcc version 8.3.0 (Debian 8.3.0-7)) #1 SMP Debian 4.19.37-3 (2019-05-15)
[ 0.000000] x86/fpu: x87 FPU will use FXSAVE
[ 0.000000] BIOS-provided physical RAM map:
[ 0.000000] BIOS-e820: [mem 0x0000000000000000-0x000000000009fbff] usable
[ 0.000000] BIOS-e820: [mem 0x000000000009fc00-0x000000000009ffff] reserved
[ 0.000000] BIOS-e820: [mem 0x00000000000dc000-0x00000000000dffff] reserved
[ 0.000000] BIOS-e820: [mem 0x00000000000f0000-0x00000000000fffff] reserved
[ 0.000000] BIOS-e820: [mem 0x0000000000100000-0x000000001fffffff] usable
[ 0.000000] BIOS-e820: [mem 0x00000000fec00000-0x00000000fec00fff] reserved
[ 0.000000] BIOS-e820: [mem 0x00000000fee00000-0x00000000fee00fff] reserved
[ 0.000000] BIOS-e820: [mem 0x00000000ffff0000-0x00000000ffffffff] reserved
[ 0.000000] Notice: NX (Execute Disable) protection missing in CPU!
[ 0.000000] Legacy DMI 2.0 present.
[ 0.000000] DMI: Micro-Star Inc. INTEL 440LX/INTEL 440LX, BIOS 0627 07/15/95
[ 0.000000] tsc: Fast TSC calibration using PIT
[ 0.000000] tsc: Detected 334.067 MHz processor
[ 0.003598] e820: update [mem 0x00000000-0x00000fff] usable ==> reserved
[ 0.003633] e820: remove [mem 0x000a0000-0x000fffff] usable
[ 0.003684] last_pfn = 0x20000 max_Arch_pfn = 0x1000000
[ 0.003731] MTRR default type: uncachable
[ 0.003741] MTRR fixed ranges enabled:
[ 0.003758] 00000-9FFFF write-back
[ 0.003773] A0000-FFFFF uncachable
[ 0.003782] MTRR variable ranges enabled:
[ 0.003798] 0 base 000000000 mask FE0000000 write-back
[ 0.003807] 1 disabled
[ 0.003815] 2 disabled
[ 0.003823] 3 disabled
[ 0.003831] 4 disabled
[ 0.003839] 5 disabled
[ 0.003847] 6 disabled
[ 0.003855] 7 disabled
[ 0.007325] x86/PAT: PAT not supported by CPU.
[ 0.007771] x86/PAT: Configuration [0-7]: WB WT UC- UC WB WT UC- UC
[ 0.050001] found SMP MP-table at [mem 0x000fb250-0x000fb25f]
[ 0.112510] initial memory mapped: [mem 0x00000000-0x1affffff]
[ 0.112544] Base memory trampoline at [(ptrval)] 9b000 size 16384
[ 0.112573] Kernel/User page tables isolation: disabled on command line.
[ 0.113047] BRK [0x1ab82000, 0x1ab83fff] PGTABLE
[ 0.113082] BRK [0x1ab84000, 0x1ab84fff] PGTABLE
[ 0.113105] BRK [0x1ab85000, 0x1ab85fff] PGTABLE
[ 0.113219] RAMDISK: [mem 0x1e40a000-0x1f885fff]
[ 0.113277] 0MB HIGHMEM available.
[ 0.113291] 512MB LOWMEM available.
[ 0.113299] mapped low ram: 0 - 20000000
[ 0.113307] low ram: 0 - 20000000
[ 0.113367] BRK [0x1ab86000, 0x1ab86fff] PGTABLE
[ 0.113399] Zone ranges:
[ 0.113408] DMA [mem 0x0000000000001000-0x0000000000ffffff]
[ 0.113425] Normal [mem 0x0000000001000000-0x000000001fffffff]
[ 0.113440] HighMem empty
[ 0.113451] Movable zone start for each node
[ 0.113457] Early memory node ranges
[ 0.113469] node 0: [mem 0x0000000000001000-0x000000000009efff]
[ 0.113480] node 0: [mem 0x0000000000100000-0x000000001fffffff]
[ 0.113496] Initmem setup node 0 [mem 0x0000000000001000-0x000000001fffffff]
[ 0.113513] On node 0 totalpages: 130974
[ 0.142335] DMA zone: 40 pages used for memmap
[ 0.142352] DMA zone: 0 pages reserved
[ 0.142364] DMA zone: 3998 pages, LIFO batch:0
[ 0.143743] Normal zone: 1240 pages used for memmap
[ 0.143760] Normal zone: 126976 pages, LIFO batch:31
[ 0.185825] Using APIC driver default
[ 0.185978] SFI: Simple Firmware Interface v0.81 http://simplefirmware.org
[ 0.194121] Intel MultiProcessor Specification v1.1
[ 0.194130] Virtual Wire compatibility mode.
[ 0.194215] MPTABLE: OEM ID: MSI
[ 0.194223] MPTABLE: Product ID:
[ 0.194233] MPTABLE: APIC at: 0xFEE00000
[ 0.194254] Processor #0 (Bootup-CPU)
[ 0.194272] Processor #1
[ 0.194367] IOAPIC[0]: apic_id 2, version 17, address 0xfec00000, GSI 0-23
[ 0.194468] Processors: 2
[ 0.194485] smpboot: Allowing 2 CPUs, 0 hotplug CPUs
[ 0.194647] PM: Registered nosave memory: [mem 0x00000000-0x00000fff]
[ 0.194669] PM: Registered nosave memory: [mem 0x0009f000-0x0009ffff]
[ 0.194679] PM: Registered nosave memory: [mem 0x000a0000-0x000dbfff]
[ 0.194688] PM: Registered nosave memory: [mem 0x000dc000-0x000dffff]
[ 0.194697] PM: Registered nosave memory: [mem 0x000e0000-0x000effff]
[ 0.194706] PM: Registered nosave memory: [mem 0x000f0000-0x000fffff]
[ 0.194733] [mem 0x20000000-0xfebfffff] available for PCI devices
[ 0.194744] Booting paravirtualized kernel on bare hardware
[ 0.194780] clocksource: refined-jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 7645519600211568 ns
[ 0.194914] random: get_random_bytes called from start_kernel+0x81/0x45f with crng_init=0
[ 0.194994] setup_percpu: NR_CPUS:32 nr_cpumask_bits:32 nr_cpu_ids:2 nr_node_ids:1
[ 0.197559] percpu: Embedded 29 pages/cpu s89932 r0 d28852 u118784
[ 0.197634] pcpu-alloc: s89932 r0 d28852 u118784 alloc=29*4096
[ 0.197648] pcpu-alloc: [0] 0 [0] 1
[ 0.197835] Built 1 zonelists, mobility grouping on. Total pages: 129694
[ 0.197861] Kernel command line: BOOT_IMAGE=/boot/vmlinuz-4.19.0-5-686-pae root=UUID=375c43d8-1ed9-48c6-a196-9787ccb61863 ro quiet acpi=off nopti nospectre_v2 nospec_store_bypass_disable
[ 0.200664] Dentry cache hash table entries: 65536 (order: 6, 262144 bytes)
[ 0.201381] Inode-cache hash table entries: 32768 (order: 5, 131072 bytes)
[ 0.201402] BRK [0x1ab87000, 0x1ab87fff] PGTABLE
[ 0.201574] Initializing CPU#0
[ 0.585340] Initializing HighMem for node 0 (00000000:00000000)
[ 0.648160] Memory: 419336K/523896K available (6751K kernel code, 660K rwdata, 2068K rodata, 880K init, 452K bss, 104560K reserved, 0K cma-reserved, 0K highmem)
[ 0.648224] virtual kernel memory layout:
fixmap : 0xffd35000 - 0xfffff000 (2856 kB)
cpu_entry : 0xff400000 - 0xff8e1000 (4996 kB)
pkmap : 0xff000000 - 0xff200000 (2048 kB)
vmalloc : 0xe0800000 - 0xfeffe000 ( 487 MB)
lowmem : 0xc0000000 - 0xe0000000 ( 512 MB)
.init : 0xda955000 - 0xdaa31000 ( 880 kB)
.data : 0xda697dd8 - 0xda945300 (2741 kB)
.text : 0xda000000 - 0xda697dd8 (6751 kB)
[ 0.648233] Checking if this processor honours the WP bit even in supervisor mode...Ok.
[ 0.649959] SLUB: HWalign=32, Order=0-3, MinObjects=0, CPUs=2, Nodes=1
[ 0.649986] ftrace: allocating 29700 entries in 59 pages
[ 0.917280] rcu: Hierarchical RCU implementation.
[ 0.917307] rcu: RCU restricting CPUs from NR_CPUS=32 to nr_cpu_ids=2.
[ 0.917321] rcu: Adjusting geometry for rcu_fanout_leaf=16, nr_cpu_ids=2
[ 0.971555] NR_IRQS: 2304, nr_irqs: 440, preallocated irqs: 16
[ 0.972398] CPU 0 irqstacks, hard=(ptrval) soft=(ptrval)
[ 0.973212] Console: colour dummy device 80x25
[ 0.973266] console [tty0] enabled
[ 0.973397] APIC: Switch to symmetric I/O mode setup
[ 0.973423] Enabling APIC mode: Flat. Using 1 I/O APICs
[ 0.973801] ExtINT not setup in hardware but reported by MP table
[ 0.975451] ..TIMER: vector=0x30 apic1=0 pin1=2 apic2=0 pin2=0
[ 0.993429] clocksource: tsc-early: mask: 0xffffffffffffffff max_cycles: 0x4d0bcc23f1, max_idle_ns: 440795205856 ns
[ 0.993549] Calibrating delay loop (skipped), value calculated using timer frequency.. 668.13 BogoMIPS (lpj=1336268)
[ 0.993579] pid_max: default: 32768 minimum: 301
[ 0.994118] Security Framework initialized
[ 0.994137] Yama: disabled by default; enable with sysctl kernel.yama.*
[ 0.994428] AppArmor: AppArmor initialized
[ 0.994682] Mount-cache hash table entries: 1024 (order: 0, 4096 bytes)
[ 0.994726] Mountpoint-cache hash table entries: 1024 (order: 0, 4096 bytes)
[ 0.997334] mce: CPU supports 5 MCE banks
[ 0.997553] Last level iTLB entries: 4KB 32, 2MB 0, 4MB 2
[ 0.997567] Last level dTLB entries: 4KB 64, 2MB 0, 4MB 8, 1GB 0
[ 0.997586] Speculative Store Bypass: Vulnerable
[ 0.997761] MDS: Vulnerable: Clear CPU buffers attempted, no microcode
[ 0.998665] Freeing SMP alternatives memory: 24K
[ 1.117524] smpboot: CPU0: Intel Pentium II (Deschutes) (family: 0x6, model: 0x5, stepping: 0x1)
[ 1.119725] Performance Events: p6 PMU driver.
[ 1.119776] ... version: 0
[ 1.119785] ... bit width: 32
[ 1.119791] ... generic registers: 2
[ 1.119800] ... value mask: 00000000ffffffff
[ 1.119808] ... max period: 000000007fffffff
[ 1.119814] ... fixed-purpose events: 0
[ 1.119821] ... event mask: 0000000000000003
[ 1.120534] rcu: Hierarchical SRCU implementation.
[ 1.126044] NMI watchdog: Enabled. Permanently consumes one hw-PMU counter.
[ 1.126734] smp: Bringing up secondary CPUs ...
[ 1.128629] CPU 1 irqstacks, hard=(ptrval) soft=(ptrval)
[ 1.128641] x86: Booting SMP configuration:
[ 1.128652] .... node #0, CPUs: #1
[ 0.005020] Initializing CPU#1
[ 0.005020] [Firmware Bug]: CPU1: APIC id mismatch. Firmware: 1 APIC: 0
[ 1.214072] smp: Brought up 1 node, 2 CPUs
[ 1.214072] smpboot: Max logical packages: 2
[ 1.214072] smpboot: Total of 2 processors activated (1336.36 BogoMIPS)
[ 1.221630] devtmpfs: initialized
[ 1.225770] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 7645041785100000 ns
[ 1.225808] futex hash table entries: 512 (order: 3, 32768 bytes)
[ 1.226504] pinctrl core: initialized pinctrl subsystem
[ 1.228901] NET: Registered protocol family 16
[ 1.230743] audit: initializing netlink subsys (disabled)
[ 1.231149] audit: type=2000 audit(1558406150.256:1): state=initialized audit_enabled=0 res=1
[ 1.231162] cpuidle: using governor ladder
[ 1.231240] cpuidle: using governor menu
[ 1.234422] PCI: Using configuration type 1 for base access
[ 1.249805] HugeTLB registered 2.00 MiB page size, pre-allocated 0 pages
[ 1.250780] ACPI: Interpreter disabled.
[ 1.254036] vgaarb: loaded
[ 1.254384] EDAC MC: Ver: 3.0.0
[ 1.255121] PCI: Probing PCI hardware
[ 1.255121] PCI: root bus 00: using default resources
[ 1.255121] PCI: Probing PCI hardware (bus 00)
[ 1.255121] PCI Host bridge to bus 0000:00
[ 1.255121] pci_bus 0000:00: root bus resource [io 0x0000-0xffff]
[ 1.255121] pci_bus 0000:00: root bus resource [mem 0x00000000-0xfffffffff]
[ 1.255121] pci_bus 0000:00: No busn resource found for root bus, will use [bus 00-ff]
[ 1.255121] pci 0000:00:00.0: [8086:7180] type 00 class 0x060000
[ 1.255121] pci 0000:00:00.0: reg 0x10: [mem 0xe8000000-0xebffffff pref]
[ 1.257972] pci 0000:00:01.0: [8086:7181] type 01 class 0x060400
[ 1.258520] pci 0000:00:07.0: [8086:7110] type 00 class 0x060100
[ 1.259061] pci 0000:00:07.1: [8086:7111] type 00 class 0x010180
[ 1.259161] pci 0000:00:07.1: reg 0x20: [io 0xffa0-0xffaf]
[ 1.259210] pci 0000:00:07.1: legacy IDE quirk: reg 0x10: [io 0x01f0-0x01f7]
[ 1.259226] pci 0000:00:07.1: legacy IDE quirk: reg 0x14: [io 0x03f6]
[ 1.259242] pci 0000:00:07.1: legacy IDE quirk: reg 0x18: [io 0x0170-0x0177]
[ 1.259256] pci 0000:00:07.1: legacy IDE quirk: reg 0x1c: [io 0x0376]
[ 1.259693] pci 0000:00:07.2: [8086:7112] type 00 class 0x0c0300
[ 1.259814] pci 0000:00:07.2: reg 0x20: [io 0xda00-0xda1f]
[ 1.260284] pci 0000:00:07.3: [8086:7113] type 00 class 0x068000
[ 1.260308] * Found PM-Timer Bug on the chipset. Due to workarounds for a bug,
* this clock source is slow. Consider trying other clock sources
[ 1.260473] pci 0000:00:07.3: quirk: [io 0x6100-0x613f] claimed by PIIX4 ACPI
[ 1.260497] pci 0000:00:07.3: quirk: [io 0x5f00-0x5f0f] claimed by PIIX4 SMB
[ 1.260979] pci 0000:00:0f.0: [13c1:1001] type 00 class 0x010400
[ 1.261046] pci 0000:00:0f.0: reg 0x10: [io 0xde00-0xde0f]
[ 1.261083] pci 0000:00:0f.0: reg 0x14: [mem 0xeffffff0-0xefffffff]
[ 1.261118] pci 0000:00:0f.0: reg 0x18: [mem 0xef000000-0xef7fffff]
[ 1.261193] pci 0000:00:0f.0: reg 0x30: [mem 0xeffe0000-0xeffeffff pref]
[ 1.261282] pci 0000:00:0f.0: supports D1
[ 1.261832] pci 0000:00:12.0: [8086:1026] type 00 class 0x020000
[ 1.261917] pci 0000:00:12.0: reg 0x10: [mem 0xeffc0000-0xeffdffff 64bit]
[ 1.261962] pci 0000:00:12.0: reg 0x18: [mem 0xeff80000-0xeffbffff 64bit]
[ 1.261996] pci 0000:00:12.0: reg 0x20: [io 0xdc00-0xdc3f]
[ 1.262046] pci 0000:00:12.0: reg 0x30: [mem 0xeff40000-0xeff7ffff pref]
[ 1.262150] pci 0000:00:12.0: PME# supported from D0 D3hot D3cold
[ 1.262701] pci_bus 0000:01: extended config space not accessible
[ 1.263002] pci 0000:00:01.0: PCI bridge to [bus 01]
[ 1.263028] pci 0000:00:01.0: bridge window [io 0xc000-0xcfff]
[ 1.263050] pci 0000:00:01.0: bridge window [mem 0xeed00000-0xeedfffff]
[ 1.263071] pci 0000:00:01.0: bridge window [mem 0xe6b00000-0xe6bfffff pref]
[ 1.263118] pci_bus 0000:00: busn_res: [bus 00-ff] end is updated to 01
[ 1.263753] pci 0000:00:07.0: PIIX/ICH IRQ router [8086:7110]
[ 1.263797] PCI: pci_cache_line_size set to 32 bytes
[ 1.263899] e820: reserve RAM buffer [mem 0x0009fc00-0x0009ffff]
[ 1.266414] clocksource: Switched to clocksource tsc-early
[ 1.447210] VFS: Disk quotas dquot_6.6.0
[ 1.447437] VFS: Dquot-cache hash table entries: 1024 (order 0, 4096 bytes)
[ 1.449141] AppArmor: AppArmor Filesystem Enabled
[ 1.449344] pnp: PnP ACPI: disabled
[ 1.449366] PnPBIOS: Scanning system for PnP BIOS support...
[ 1.449800] PnPBIOS: Found PnP BIOS installation structure at 0x(ptrval)
[ 1.449823] PnPBIOS: PnP BIOS version 1.0, entry 0xf0000:0x6dae, dseg 0xf0000
[ 1.450617] pnp 00:00: [mem 0x00000000-0x0009fbff]
[ 1.450638] pnp 00:00: [mem 0x0009fc00-0x0009ffff]
[ 1.450655] pnp 00:00: [mem 0x000dc000-0x000dffff]
[ 1.450670] pnp 00:00: [mem 0x000f0000-0x000fffff]
[ 1.450687] pnp 00:00: [mem 0x00100000-0x1fffffff]
[ 1.450705] pnp 00:00: [mem 0xfffffffffec00000-0xfffffffffec00fff]
[ 1.450723] pnp 00:00: [mem 0xfffffffffee00000-0xfffffffffee00fff]
[ 1.450741] pnp 00:00: [mem 0xffffffffffff0000-0xffffffffffffffff]
[ 1.451159] system 00:00: [mem 0x00000000-0x0009fbff] could not be reserved
[ 1.451184] system 00:00: [mem 0x0009fc00-0x0009ffff] could not be reserved
[ 1.451206] system 00:00: [mem 0x000dc000-0x000dffff] could not be reserved
[ 1.451227] system 00:00: [mem 0x000f0000-0x000fffff] could not be reserved
[ 1.451247] system 00:00: [mem 0x00100000-0x1fffffff] could not be reserved
[ 1.451269] system 00:00: [mem 0xfffffffffec00000-0xfffffffffec00fff] could not be reserved
[ 1.451291] system 00:00: [mem 0xfffffffffee00000-0xfffffffffee00fff] could not be reserved
[ 1.451313] system 00:00: [mem 0xffffffffffff0000-0xffffffffffffffff] could not be reserved
[ 1.451377] system 00:00: Plug and Play BIOS device, IDs PNP0c01 (active)
[ 1.451513] pnp 00:01: [io 0x0020-0x0021]
[ 1.451531] pnp 00:01: [io 0x00a0-0x00a1]
[ 1.451551] pnp 00:01: [irq 2]
[ 1.451749] pnp 00:01: Plug and Play BIOS device, IDs PNP0000 (active)
[ 1.451906] pnp 00:02: [dma 4]
[ 1.451924] pnp 00:02: [io 0x0000-0x000f]
[ 1.451941] pnp 00:02: [io 0x0080-0x0090]
[ 1.451957] pnp 00:02: [io 0x0094-0x009f]
[ 1.451974] pnp 00:02: [io 0x00c0-0x00de]
[ 1.452200] pnp 00:02: Plug and Play BIOS device, IDs PNP0200 (active)
[ 1.452437] pnp 00:03: [irq 0]
[ 1.452457] pnp 00:03: [io 0x0040-0x0043]
[ 1.452662] pnp 00:03: Plug and Play BIOS device, IDs PNP0100 (active)
[ 1.452853] pnp 00:04: [irq 8]
[ 1.452872] pnp 00:04: [io 0x0070-0x0071]
[ 1.453068] pnp 00:04: Plug and Play BIOS device, IDs PNP0b00 (active)
[ 1.453277] pnp 00:05: [irq 1]
[ 1.453296] pnp 00:05: [io 0x0060]
[ 1.453312] pnp 00:05: [io 0x0064]
[ 1.453534] pnp 00:05: Plug and Play BIOS device, IDs PNP0303 (active)
[ 1.453761] pnp 00:06: [io 0x0061]
[ 1.453964] pnp 00:06: Plug and Play BIOS device, IDs PNP0800 (active)
[ 1.454248] pnp 00:07: [irq 13]
[ 1.454268] pnp 00:07: [io 0x00f0-0x00ff]
[ 1.454468] pnp 00:07: Plug and Play BIOS device, IDs PNP0c04 (active)
[ 1.454798] pnp 00:08: [io 0x6100-0x613f]
[ 1.454816] pnp 00:08: [io 0x5f00-0x5f0f]
[ 1.454833] pnp 00:08: [io 0x04d0-0x04d1]
[ 1.454849] pnp 00:08: [io 0x0cf8-0x0cff]
[ 1.454866] pnp 00:08: [io 0x0294-0x0297]
[ 1.455088] pnp 00:08: Plug and Play BIOS device, IDs PNP0a03 (active)
[ 1.455104] PnPBIOS: 9 nodes reported by PnP BIOS; 9 recorded by driver
[ 1.483560] pci 0000:00:01.0: PCI bridge to [bus 01]
[ 1.483590] pci 0000:00:01.0: bridge window [io 0xc000-0xcfff]
[ 1.483619] pci 0000:00:01.0: bridge window [mem 0xeed00000-0xeedfffff]
[ 1.483642] pci 0000:00:01.0: bridge window [mem 0xe6b00000-0xe6bfffff pref]
[ 1.483684] pci_bus 0000:00: resource 4 [io 0x0000-0xffff]
[ 1.483701] pci_bus 0000:00: resource 5 [mem 0x00000000-0xfffffffff]
[ 1.483719] pci_bus 0000:01: resource 0 [io 0xc000-0xcfff]
[ 1.483735] pci_bus 0000:01: resource 1 [mem 0xeed00000-0xeedfffff]
[ 1.483752] pci_bus 0000:01: resource 2 [mem 0xe6b00000-0xe6bfffff pref]
[ 1.484194] NET: Registered protocol family 2
[ 1.486277] tcp_listen_portaddr_hash hash table entries: 512 (order: 0, 6144 bytes)
[ 1.486370] TCP established hash table entries: 4096 (order: 2, 16384 bytes)
[ 1.486499] TCP bind hash table entries: 4096 (order: 3, 32768 bytes)
[ 1.486722] TCP: Hash tables configured (established 4096 bind 4096)
[ 1.487123] UDP hash table entries: 256 (order: 1, 8192 bytes)
[ 1.487199] UDP-Lite hash table entries: 256 (order: 1, 8192 bytes)
[ 1.487734] NET: Registered protocol family 1
[ 1.487803] NET: Registered protocol family 44
[ 1.487854] pci 0000:00:00.0: Limiting direct PCI/PCI transfers
[ 1.488032] pci 0000:00:07.2: PCI->APIC IRQ transform: INT D -> IRQ 19
[ 1.488142] PCI: CLS 32 bytes, default 32
[ 1.488902] Unpacking initramfs...
[ 6.074902] Freeing initrd memory: 20976K
[ 6.074945] PCI-DMA: Using software bounce buffering for IO (SWIOTLB)
[ 6.074962] software IO TLB: mapped [mem 0x16000000-0x1a000000] (64MB)
[ 6.082796] Initialise system trusted keyrings
[ 6.082913] Key type blacklist registered
[ 6.083606] workingset: timestamp_bits=14 max_order=17 bucket_order=3
[ 6.105277] zbud: loaded
[ 6.106749] pstore: using deflate compression
[ 7.084935] clocksource: tsc: mask: 0xffffffffffffffff max_cycles: 0x4d0bcc23f1, max_idle_ns: 440795205856 ns
[ 7.085417] clocksource: Switched to clocksource tsc
[ 13.550142] Key type asymmetric registered
[ 13.550166] Asymmetric key parser 'x509' registered
[ 13.550341] Block layer SCSI generic (bsg) driver version 0.4 loaded (major 249)
[ 13.550843] io scheduler noop registered
[ 13.550856] io scheduler deadline registered
[ 13.551678] io scheduler cfq registered (default)
[ 13.551693] io scheduler mq-deadline registered
[ 13.553675] shpchp: Standard Hot Plug PCI Controller Driver version: 0.4
[ 13.553857] intel_idle: does not run on family 6 model 5
[ 13.554345] isapnp: Scanning for PnP cards...
[ 13.909492] isapnp: No Plug & Play device found
[ 13.910403] Serial: 8250/16550 driver, 4 ports, IRQ sharing enabled
[ 13.916097] Linux agpgart interface v0.103
[ 13.917233] agpgart-intel 0000:00:00.0: Intel 440LX Chipset
[ 13.931948] agpgart-intel 0000:00:00.0: AGP aperture is 64M @ 0xe8000000
[ 13.933568] i8042: PNP: PS/2 Controller [PNP0303] at 0x60,0x64 irq 1
[ 13.933580] i8042: PNP: PS/2 appears to have AUX port disabled, if this is incorrect please boot with i8042.nopnp
[ 13.935121] serio: i8042 KBD port at 0x60,0x64 irq 1
[ 13.936491] mousedev: PS/2 mouse device common for all mice
[ 13.937133] rtc rtc0: invalid alarm value: 2019-5-21 22:62:30
[ 13.937659] rtc_cmos 00:04: registered as rtc0
[ 13.937885] rtc_cmos 00:04: alarms up to one day, 114 bytes nvram
[ 13.938244] ledtrig-cpu: registered to indicate activity on CPUs
[ 13.942928] NET: Registered protocol family 10
[ 14.055107] Segment Routing with IPv6
[ 14.055356] mip6: Mobile IPv6
[ 14.055378] NET: Registered protocol family 17
[ 14.055902] mpls_gso: MPLS GSO support
[ 14.058256] microcode: sig=0x651, pf=0x1, revision=0x29
[ 14.058821] microcode: Microcode Update Driver: v2.2.
[ 14.058856] Using IPI No-Shortcut mode
[ 14.058925] sched_clock: Marking stable (14057713765, 1020469)->(14183988558, -125254324)
[ 14.060943] registered taskstats version 1
[ 14.060953] Loading compiled-in X.509 certificates
[ 15.760453] Loaded X.509 cert 'Debian Secure Boot CA: 6ccece7e4c6c0d1f6149f3dd27dfcc5cbb419ea1'
[ 15.760690] Loaded X.509 cert 'Debian Secure Boot Signer: 00a7468def'
[ 15.760897] zswap: loaded using pool lzo/zbud
[ 15.761440] AppArmor: AppArmor sha1 policy hashing enabled
[ 15.763226] rtc_cmos 00:04: setting system clock to 2019-05-21 02:36:05 UTC (1558406165)
[ 15.780688] Freeing unused kernel image memory: 880K
[ 15.798080] Write protecting the kernel text: 6752k
[ 15.798691] Write protecting the kernel read-only data: 2076k
[ 15.798752] Run /init as init process
[ 16.675094] piix4_smbus 0000:00:07.3: SMBus Host Controller at 0x5f00, revision 0
[ 16.812021] e1000: Intel(R) PRO/1000 Network Driver - version 7.3.21-k8-NAPI
[ 16.812035] e1000: Copyright (c) 1999-2006 Intel Corporation.
[ 16.812295] e1000 0000:00:12.0: PCI->APIC IRQ transform: INT A -> IRQ 19
[ 16.874559] SCSI subsystem initialized
[ 16.918301] 3ware Storage Controller device driver for Linux v1.26.02.003.
[ 16.918545] 3w-xxxx 0000:00:0f.0: PCI->APIC IRQ transform: INT A -> IRQ 17
[ 16.963692] usbcore: registered new interface driver usbfs
[ 16.963847] usbcore: registered new interface driver hub
[ 16.964206] usbcore: registered new device driver usb
[ 17.044883] ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver
[ 17.100093] uhci_hcd: USB Universal Host Controller Interface driver
[ 17.100429] uhci_hcd 0000:00:07.2: PCI->APIC IRQ transform: INT D -> IRQ 19
[ 17.100531] uhci_hcd 0000:00:07.2: UHCI Host Controller
[ 17.100597] uhci_hcd 0000:00:07.2: new USB bus registered, assigned bus number 1
[ 17.100646] uhci_hcd 0000:00:07.2: detected 2 ports
[ 17.100846] uhci_hcd 0000:00:07.2: irq 19, io base 0x0000da00
[ 17.112769] usb usb1: New USB device found, idVendor=1d6b, idProduct=0001, bcdDevice= 4.19
[ 17.112788] usb usb1: New USB device strings: Mfr=3, Product=2, SerialNumber=1
[ 17.112803] usb usb1: Product: UHCI Host Controller
[ 17.112817] usb usb1: Manufacturer: Linux 4.19.0-5-686-pae uhci_hcd
[ 17.112831] usb usb1: SerialNumber: 0000:00:07.2
[ 17.117845] hub 1-0:1.0: USB hub found
[ 17.117955] hub 1-0:1.0: 2 ports detected
[ 17.288567] e1000 0000:00:12.0 eth0: (PCI:33MHz:32-bit) 00:04:23:e0:09:16
[ 17.288626] e1000 0000:00:12.0 eth0: Intel(R) PRO/1000 Network Connection
[ 17.300598] e1000 0000:00:12.0 enp0s18: renamed from eth0
[ 23.253605] scsi Host0: 3ware Storage Controller
[ 23.260297] 3w-xxxx: scsi0: Found a 3ware Storage Controller at 0xde00, IRQ: 17.
[ 23.266809] scsi 0:0:0:0: Direct-Access 3ware Logical Disk 0 1.2 PQ: 0 ANSI: 0
[ 23.389261] sd 0:0:0:0: [sda] 468862128 512-byte logical blocks: (240 GB/224 GiB)
[ 23.389368] sd 0:0:0:0: [sda] Write Protect is off
[ 23.389388] sd 0:0:0:0: [sda] Mode Sense: 00 00 00 00
[ 23.389934] sd 0:0:0:0: [sda] Write cache: enabled, read cache: disabled, supports DPO and FUA
[ 23.396290] sda: sda1 sda2 < sda5 >
[ 23.400739] sd 0:0:0:0: [sda] Attached SCSI disk
[ 23.754215] PM: Image not found (code -22)
[ 23.942763] random: fast init done
[ 24.167537] cryptd: max_cpu_qlen set to 1000
[ 24.854773] EXT4-fs (sda1): mounted filesystem with ordered data mode. Opts: (null)
[ 25.846221] systemd[1]: Inserted module 'autofs4'
[ 25.963217] systemd[1]: systemd 241 running in system mode. (+PAM +AUDIT +SELINUX +IMA +APPARMOR +SMACK +SYSVINIT +UTMP +LIBCRYPTSETUP +GCRYPT +GNUTLS +ACL +XZ +LZ4 +SECCOMP +BLKID +ELFUTILS +KMOD -IDN2 +IDN -PCRE2 default-hierarchy=hybrid)
[ 25.964788] systemd[1]: Detected architecture x86.
[ 25.981252] systemd[1]: Set hostname to <crumble0>.
[ 27.477851] random: systemd: uninitialized urandom read (16 bytes read)
[ 27.494867] random: systemd: uninitialized urandom read (16 bytes read)
[ 27.495052] systemd[1]: Reached target System Time Synchronized.
[ 27.496154] random: systemd: uninitialized urandom read (16 bytes read)
[ 27.497675] systemd[1]: Listening on udev Kernel Socket.
[ 27.498640] systemd[1]: Listening on initctl Compatibility Named Pipe.
[ 27.500200] systemd[1]: Listening on udev Control Socket.
[ 27.500545] systemd[1]: Reached target Remote File Systems.
[ 27.502280] systemd[1]: Listening on Syslog Socket.
[ 27.503755] systemd[1]: Listening on fsck to fsckd communication Socket.
[ 28.222652] EXT4-fs (sda1): re-mounted. Opts: errors=remount-ro
[ 28.279034] random: crng init done
[ 28.279061] random: 7 urandom warning(s) missed due to ratelimiting
[ 29.799983] systemd-journald[164]: Received request to flush runtime journal from PID 1
[ 30.352511] sd 0:0:0:0: Attached scsi generic sg0 type 0
[ 32.152329] Adding 522236k swap on /dev/sda5. Priority:-2 extents:1 across:522236k FS
[ 32.721332] IPv6: ADDRCONF(NETDEV_UP): enp0s18: link is not ready
[ 32.726115] e1000: enp0s18 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX/TX
[ 32.726351] IPv6: ADDRCONF(NETDEV_CHANGE): enp0s18: link becomes ready
編集：
$ Sudo cat /proc/iomem
00000000-00000fff : Reserved
00001000-0009fbff : System RAM
0009fc00-0009ffff : Reserved
000a0000-000bffff : Video RAM area
000c8000-000c8fff : Adapter ROM
000dc000-000dffff : Reserved
000f0000-000fffff : Reserved
000f0000-000fffff : System ROM
00100000-1fffffff : System RAM
1a000000-1a697dd7 : Kernel code
1a697dd8-1a9452ff : Kernel data
1aa38000-1aaa8fff : Kernel bss
e6b00000-e6bfffff : PCI Bus 0000:01
e8000000-ebffffff : 0000:00:00.0
eed00000-eedfffff : PCI Bus 0000:01
ef000000-ef7fffff : 0000:00:0f.0
ef000000-ef7fffff : 3w-xxxx
eff40000-eff7ffff : 0000:00:12.0
eff80000-effbffff : 0000:00:12.0
eff80000-effbffff : e1000
effc0000-effdffff : 0000:00:12.0
effc0000-effdffff : e1000
effe0000-effeffff : 0000:00:0f.0
effffff0-efffffff : 0000:00:0f.0
effffff0-efffffff : 3w-xxxx
fec00000-fec00fff : Reserved
fec00000-fec003ff : IOAPIC 0
fee00000-fee00fff : Local APIC
fee00000-fee00fff : Reserved
ffff0000-ffffffff : Reserved
SWIOTLBがシステムで有効になっています。デフォルトでは、64M RAMが予約されています。 4Gを超えるRAMがあり、ハードウェアIOMMUを使用できない場合、またはネストされたページテーブルのないXen仮想化で実行している場合にのみ必要です。おめでとう。カーネルにバグが見つかりました:-)。
次のブートオプションのいずれかが正常に機能します。
- _
iommu=off_-SWIOTLBを無効にします。 - _
swiotlb=1_-SWIOTLBを1つの「スラブ」= 128Kに減らします。
または、カーネルのソースコードにパッチを当てることもできます。パッチとそれが修正するバグの説明については以下を参照してください:-)。
問題分析
_[ 0.000000] BIOS-provided physical RAM map:
[ 0.000000] BIOS-e820: [mem 0x0000000000000000-0x000000000009fbff] usable
[ 0.000000] BIOS-e820: [mem 0x000000000009fc00-0x000000000009ffff] reserved
[ 0.000000] BIOS-e820: [mem 0x00000000000dc000-0x00000000000dffff] reserved
[ 0.000000] BIOS-e820: [mem 0x00000000000f0000-0x00000000000fffff] reserved
[ 0.000000] BIOS-e820: [mem 0x0000000000100000-0x000000001fffffff] usable
_あなたの物理的なRAMは0-512Mからマッピングされています。通常のレガシーナンセンスから始めますが、それは1M未満の領域にのみ影響します（_0x100000_）。
_[ 0.113219] RAMDISK: [mem 0x1e40a000-0x1f885fff]
_初期のramdiskは約20Mを占めます。
[ 0.648160] Memory: 419336K/523896K available (6751K kernel code, 660K rwdata, 2068K rodata, 880K init, 452K bss, 104560K reserved, 0K cma-reserved, 0K highmem)
しかし、現在104Mが予約されています。これには、後で解放されるinitrdが含まれていると思います。
_[ 6.074902] Freeing initrd memory: 20976K
_損失の大部分はここにあると思います：
_[ 6.074945] PCI-DMA: Using software bounce buffering for IO (SWIOTLB)
[ 6.074962] software IO TLB: mapped [mem 0x16000000-0x1a000000] (64MB)
_64Mは デフォルトサイズ バウンスバッファに割り当てられます。
Swiotlbは、システムのすべてのメモリにアクセスできない[DMA]デバイスで使用されるバウンスバッファリングメカニズムです。
Swiotlbコードは、bootstrapプロセスの早い段階で低メモリの大きなチャンクを割り当てるだけです。このメモリは、DMA割り当て要求に応じて渡されます。多くの場合、場合によっては、swiotlbメモリの使用には、データがドライバのバッファとデバイスからアクセス可能なswiotlbスペースとの間でコピーされる「バウンスバッファ」の作成が含まれます。swiotlbに使用されるメモリは、通常のLinuxメモリ管理メカニズムから削除されているため、 DMA buffers以外の用途ではアクセスできません。これらの理由により、swiotlbはせいぜいエレガントではないと見なされています。
DMAの問題、パート2 、LWN.net、2004年。
この説明の奇妙な点は、swiotlbがIntelのx86-64の初期実装の回避策だったということです。あなたはx86-32 Linuxの現在の荒廃した状態に失敗したようです。 Linuxが多くのx86-32およびx86-64コードを「統合」したときの見落としでしょうか。
SWIOTLB初期化コード は、4GB以下のシステムでは有効にすべきではないことを意味します...しかし、壊れていると思います:-D。
_/* 4GB broken PCI/AGP hardware bus master zone */
#define MAX_DMA32_PFN ((4UL * 1024 * 1024 * 1024) >> PAGE_SHIFT)
...
* If 4GB or more detected (and iommu=off not set) or if SME is active
* then set swiotlb to 1 and return 1.
*/
int __init pci_swiotlb_detect_4gb(void)
{
/* don't initialize swiotlb if iommu=off (no_iommu=1) */
if (!no_iommu && max_possible_pfn > MAX_DMA32_PFN)
swiotlb = 1;
_問題は、32ビット:-D用にビルドする場合、_4UL * 1024 * 1024 * 1024_が_0_に評価されることです。
修正は次のようになります
_Arch/x86/include/asm/dma.h:
-#define MAX_DMA32_PFN ((4UL * 1024 * 1024 * 1024) >> PAGE_SHIFT)
+#define MAX_DMA32_PFN (4UL * ((1024 * 1024 * 1024) >> PAGE_SHIFT)))
_このカーネルパッチをGPL2の下で（そしてパブリックドメインにも）リリースします。テストまたは提出する予定はありません。この知識で何をするか。