+ Hugh and Patrick.
On Thu, Dec 09, 2021 at 09:38:10AM -0500, John Dorminy wrote:
> 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.
Yeah, people have been reporting boot failures with mem= on the cmdline.
I think I see why, can you try this one:
---
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 6a190c7f4d71..6db971e61e4b 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -862,6 +862,8 @@ void __init setup_arch(char **cmdline_p)
*/
x86_configure_nx();
+ e820__memory_setup();
+
/*
* This parses early params and it needs to run before
* early_reserve_memory() because latter relies on such settings
@@ -884,7 +886,6 @@ void __init setup_arch(char **cmdline_p)
early_reserve_memory();
iomem_resource.end = (1ULL << boot_cpu_data.x86_phys_bits) - 1;
- e820__memory_setup();
parse_setup_data();
copy_edd();
---
Leaving in the rest for the newly added folks.
> 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)
>
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
