Greetings; It seems that this patch causes a mem= parameter to the kernel to have no effect, unfortunately... As far as I understand, the x86 mem parameter handler parse_memopt() (called by parse_early_param()) relies on being called after e820__memory_setup(): it simply removes any memory above the specified limit at that moment, allowing memory to later be hotplugged without regard for the initial limit. However, the initial non-hotplugged memory must already have been set up, in e820__memory_setup(), so that it can be removed in parse_memopt(); if parse_early_param() is called before e820__memory_setup(), as this change does, the parameter ends up having no effect. I apologize that I don't know how to fix this, but I'm happy to test patches. Typical dmesg output showing the lack of effect, built from the prior change and this change: With a git tree synced to 8d48bf8206f77aa8687f0e241e901e5197e52423^ (working): [ 0.000000] Command line: BOOT_IMAGE=(hd0,msdos1)/boot/vmlinuz-5.16.0-rc1 root=UUID=a4f7bd84-4f29-40bc-8c98-f4a72d0856c4 ro net.ifnames=0 crashkernel=128M mem=4G ... [ 0.000000] BIOS-provided physical RAM map: [ 0.000000] BIOS-e820: [mem 0x0000000000000000-0x000000000009abff] usable [ 0.000000] BIOS-e820: [mem 0x000000000009ac00-0x000000000009ffff] reserved [ 0.000000] BIOS-e820: [mem 0x00000000000e0000-0x00000000000fffff] reserved [ 0.000000] BIOS-e820: [mem 0x0000000000100000-0x000000007dd3afff] usable [ 0.000000] BIOS-e820: [mem 0x000000007dd3b000-0x000000007deeffff] reserved [ 0.000000] BIOS-e820: [mem 0x000000007def0000-0x000000007e0d3fff] ACPI NVS [ 0.000000] BIOS-e820: [mem 0x000000007e0d4000-0x000000007f367fff] reserved [ 0.000000] BIOS-e820: [mem 0x000000007f368000-0x000000007f7fffff] ACPI NVS [ 0.000000] BIOS-e820: [mem 0x0000000080000000-0x000000008fffffff] reserved [ 0.000000] BIOS-e820: [mem 0x00000000fed1c000-0x00000000fed3ffff] reserved [ 0.000000] BIOS-e820: [mem 0x00000000ff000000-0x00000000ffffffff] reserved [ 0.000000] BIOS-e820: [mem 0x0000000100000000-0x000000207fffffff] usable [ 0.000000] e820: remove [mem 0x100000000-0xfffffffffffffffe] usable [ 0.000000] NX (Execute Disable) protection: active [ 0.000000] user-defined physical RAM map: [ 0.000000] user: [mem 0x0000000000000000-0x000000000009abff] usable [ 0.000000] user: [mem 0x000000000009ac00-0x000000000009ffff] reserved [ 0.000000] user: [mem 0x00000000000e0000-0x00000000000fffff] reserved [ 0.000000] user: [mem 0x0000000000100000-0x000000007dd3afff] usable [ 0.000000] user: [mem 0x000000007dd3b000-0x000000007deeffff] reserved [ 0.000000] user: [mem 0x000000007def0000-0x000000007e0d3fff] ACPI NVS [ 0.000000] user: [mem 0x000000007e0d4000-0x000000007f367fff] reserved [ 0.000000] user: [mem 0x000000007f368000-0x000000007f7fffff] ACPI NVS [ 0.000000] user: [mem 0x0000000080000000-0x000000008fffffff] reserved [ 0.000000] user: [mem 0x00000000fed1c000-0x00000000fed3ffff] reserved [ 0.000000] user: [mem 0x00000000ff000000-0x00000000ffffffff] reserved ... [ 0.025617] Memory: 1762876K/2061136K available (16394K kernel code, 3568K rwdata, 10324K rodata, 2676K init, 4924K bss, 298000K reserved, 0K cma-reserved) Synced 8d48bf8206f77aa8687f0e241e901e5197e52423 (not working): [ 0.000000] Command line: BOOT_IMAGE=(hd0,msdos1)/boot/vmlinuz-5.16.0-rc4+ root=UUID=0e750e61-b92e-4708-a974-c50a3fb7e969 ro net.ifnames=0 crashkernel=128M mem=4G [ 0.000000] e820: remove [mem 0x100000000-0xfffffffffffffffe] usable [ 0.000000] BIOS-provided physical RAM map: [ 0.000000] BIOS-e820: [mem 0x0000000000000000-0x000000000009abff] usable [ 0.000000] BIOS-e820: [mem 0x000000000009ac00-0x000000000009ffff] reserved [ 0.000000] BIOS-e820: [mem 0x00000000000e0000-0x00000000000fffff] reserved [ 0.000000] BIOS-e820: [mem 0x0000000000100000-0x000000007dd3afff] usable [ 0.000000] BIOS-e820: [mem 0x000000007dd3b000-0x000000007deeffff] reserved [ 0.000000] BIOS-e820: [mem 0x000000007def0000-0x000000007e0d3fff] ACPI NVS [ 0.000000] BIOS-e820: [mem 0x000000007e0d4000-0x000000007f367fff] reserved [ 0.000000] BIOS-e820: [mem 0x000000007f368000-0x000000007f7fffff] ACPI NVS [ 0.000000] BIOS-e820: [mem 0x0000000080000000-0x000000008fffffff] reserved [ 0.000000] BIOS-e820: [mem 0x00000000fed1c000-0x00000000fed3ffff] reserved [ 0.000000] BIOS-e820: [mem 0x00000000ff000000-0x00000000ffffffff] reserved [ 0.000000] BIOS-e820: [mem 0x0000000100000000-0x000000207fffffff] usable [ 0.000000] NX (Execute Disable) protection: active [ 0.000000] user-defined physical RAM map: [ 0.000000] user: [mem 0x0000000000000000-0x000000000009abff] usable [ 0.000000] user: [mem 0x000000000009ac00-0x000000000009ffff] reserved [ 0.000000] user: [mem 0x00000000000e0000-0x00000000000fffff] reserved [ 0.000000] user: [mem 0x0000000000100000-0x000000007dd3afff] usable [ 0.000000] user: [mem 0x000000007dd3b000-0x000000007deeffff] reserved [ 0.000000] user: [mem 0x000000007def0000-0x000000007e0d3fff] ACPI NVS [ 0.000000] user: [mem 0x000000007e0d4000-0x000000007f367fff] reserved [ 0.000000] user: [mem 0x000000007f368000-0x000000007f7fffff] ACPI NVS [ 0.000000] user: [mem 0x0000000080000000-0x000000008fffffff] reserved [ 0.000000] user: [mem 0x00000000fed1c000-0x00000000fed3ffff] reserved [ 0.000000] user: [mem 0x00000000ff000000-0x00000000ffffffff] reserved [ 0.000000] user: [mem 0x0000000100000000-0x000000207fffffff] usable ... [ 0.695267] Memory: 131657608K/134181712K available (16394K kernel code, 3568K rwdata, 10328K rodata, 2676K init, 4924K bss, 2523844K reserved, 0K cma-reserved)
