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Date:   Thu, 03 Dec 2020 17:27:45 +0800
From:   Jiaxun Yang <jiaxun.yang@flygoat.com>
To:     Jinyang He <hejinyang@loongson.cn>,
        Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
        Huacai Chen <chenhc@lemote.com>
CC:     linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] MIPS: Add fix_range_node after parse "mem=" parameter
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=E4=BA=8E 2020=E5=B9=B412=E6=9C=883=E6=97=A5 GMT+08:00 =E4=B8=8B=E5=8D=884=
:57:47, Jinyang He <hejinyang@loongson=2Ecn> =E5=86=99=E5=88=B0:
>This problem may only occur on NUMA platforms=2E When machine start
>with the "mem=3D" parameter on Loongson64, it cannot boot=2E When parsing=
 the
>"mem=3D" parameter, first all the RAM was removed, and then the memory wa=
s
>not added by memblock_add_node(), which caused the newly added memory to
>be on MAX_NUMNODES=2E The key to solve this problem is to fix these memor=
y
>nodes through memblock_set_node() before bootmem_init() or earlier=2E So
>it would be better to fix it before check_kernel_sections_mem()=2E
>The check_kernel_sections_mem() will check whether the current RAM can be
>used by the kernel=2E If this fix is added after that, it will do a redun=
dant
>memblock_add operation=2E Adding the fixup_region_node() function can als=
o
>provide a reference for future platforms using NUMA when encountering
>such problems=2E

Hi Jingyang,

Is it possible to do it when parsing cmdline to avoid this kind of fixup?

Thanks=2E

- Jiaxun

>
>Signed-off-by: Jinyang He <hejinyang@loongson=2Ecn>
>---
> arch/mips/include/asm/bootinfo=2Eh |  1 +
> arch/mips/kernel/setup=2Ec         |  6 +++++-
> arch/mips/loongson64/numa=2Ec      | 11 +++++++++++
> 3 files changed, 17 insertions(+), 1 deletion(-)
>
>diff --git a/arch/mips/include/asm/bootinfo=2Eh b/arch/mips/include/asm/b=
ootinfo=2Eh
>index aa03b12=2E=2Eddc17b1 100644
>--- a/arch/mips/include/asm/bootinfo=2Eh
>+++ b/arch/mips/include/asm/bootinfo=2Eh
>@@ -91,6 +91,7 @@ const char *get_system_type(void);
> extern unsigned long mips_machtype;
>=20
> extern void detect_memory_region(phys_addr_t start, phys_addr_t sz_min, =
 phys_addr_t sz_max);
>+extern void fixup_region_node(void);
>=20
> extern void prom_init(void);
> extern void prom_free_prom_memory(void);
>diff --git a/arch/mips/kernel/setup=2Ec b/arch/mips/kernel/setup=2Ec
>index b3a711e=2E=2Efe93882 100644
>--- a/arch/mips/kernel/setup=2Ec
>+++ b/arch/mips/kernel/setup=2Ec
>@@ -110,6 +110,8 @@ void __init detect_memory_region(phys_addr_t start, p=
hys_addr_t sz_min, phys_add
> 	memblock_add(start, size);
> }
>=20
>+void __weak fixup_region_node(void) {}
>+
> /*
>  * Manage initrd
>  */
>@@ -631,8 +633,10 @@ static void __init arch_mem_init(char **cmdline_p)
>=20
> 	parse_early_param();
>=20
>-	if (usermem)
>+	if (usermem) {
> 		pr_info("User-defined physical RAM map overwrite\n");
>+		fixup_region_node();
>+	}
>=20
> 	check_kernel_sections_mem();
>=20
>diff --git a/arch/mips/loongson64/numa=2Ec b/arch/mips/loongson64/numa=2E=
c
>index c6f0c48=2E=2Ed8661cc 100644
>--- a/arch/mips/loongson64/numa=2Ec
>+++ b/arch/mips/loongson64/numa=2Ec
>@@ -220,6 +220,17 @@ void __init mem_init(void)
> 	mem_init_print_info(NULL);
> }
>=20
>+void __init fixup_region_node(void)
>+{
>+	phys_addr_t start, end;
>+	u64 i;
>+
>+	for_each_mem_range(i, &start, &end) {
>+		memblock_set_node(start, end - start,
>+				  &memblock=2Ememory, pa_to_nid(start));
>+	}
>+}
>+
> /* All PCI device belongs to logical Node-0 */
> int pcibus_to_node(struct pci_bus *bus)
> {