Memory Split (user:kernel) config

1,memory Split original value [Xiatian@ling45 lfs_linux]$ git grep "Memory split" arch/arm/kconfig:prompt "Memory Split" Arch/tile/kconfig:prompt "Memory Split" if expert arch/x86/kconfig:prompt "memory split" if expert
Arch/arm/kconfig:choice prompt "Memory split" default vmsplit_3g help Select the desired split between kernel and user m Emory. If you aren't absolutely sure what is doing, leave this option alone! Config vmsplit_3g bool "3g/1g user/kernel split" config vmsplit_2g bool " 2g/2g User/kernel Split"Config vmsplit_1g bool" 1g/3g user/kernel split "Endchoice
Arch/arm/configs/xx_defconfig:

. config:
2, [xiatian@ling45 lfs_linux]$ export arch=arm [xiatian@ling45 lfs_linux]$ make Menuconfig Kernel Features--->


(IMPORTANT!!! If you have just started to modify. config to the following values, make Menuconfig will display: Memory split (1g/3g user/kernel split)---> (x) 1g/3g User/kernel split. confi G: # config_vmsplit_3g is not set # config_vmsplit_2g are not set config_vmsplit_1g=y)
3, if the memory is modified to the following, the file will be saved to the. config.





4, the. config copy to the Arch/arm/configs/xx_defconfig configuration is in effect.
The Config_page_offset value can also be changed accordingly (according to Arch/arm/kconfig's logic)
5, compiled on the board to run, Kernel:user into a 1g:3g
Before change:root@xx-b-7:~# Journalctl | grep TIAN Jan 00:00:03-xx-b-7 Kernel:tian nr_bankes=2 Jan-00:00:03 xx-b-7 Kernel:tian vmalloc_limit (PHY) =0x6f8000 XX, Vmalloc_min (VA) =0xef800000, vmalloc_start=0x800000, vmalloc_end=0xff000000 Jan, 00:00:03 xx-b-7 Kernel:tian bank[ 0].size=534773760, Bank[0].highmem=0, Bank[0].start (PHY) =0x0, 00:00:03 xx-b-7 kernel:tian CONFIG_HIGHMEM defined, nr_banks=8 Jan 00:00:03 xx-b-7 Kernel:tian bank[1].size=2080374784, Bank[0].highmem=1, Bank[1].start (PHY) =0x1 Jan 01 0 Kernel:tian Config_highmem defined, nr_banks=8 0:00:03-xx-b-7 00:00:03 xx-b-7 kernel:tian high_memory_0 (VA) =0x9f e00000, (PHY) 0x1fe00000; High_memory_1 (VA) =0x9fdfffff, (PHY) 0x1fdfffff Jan 00:00:03 xx-b-7 Kernel:tian meminfo.nr_banks=2, high_memory (VA) = 0x9fe00000 Jan 00:00:03 xx-b-7 kernel:tian Virtual kernel memory Layout:tian vector:0xffff0000-0xffff1000 (4 KB) TIAN fixmap:0xfff00000-0xfffe0000 (896 KB) TIAN vmalloc:0xa0000000-0xff000(1520 MB) TIAN Lowmem: 0x80000000 -0x9fe00000 (510 MB) TIAN pkmap:0x7fe00000-0x80000000 (2 MB) TIAN modules:0x7f800000-0x7fe00000 (6 MB) TIAN. TEXT:0X80008000-0X80376AA4 (3515 KB) TIAN. INIT:0X80377000-0X803F73C0 (513 kb) TIAN. data:0x803f8000-0x804479 (319 KB) TIAN. Bss:0x80447950-0x804b8ee4 (454 kb) TIAN arm_lowmem_limit=0x1fe00000, high_memory=0x9fe00000 after Change:jan 00:00:03 xx-b-7 Kernel:tian nr_bankes=2, 00:00:03 xx-b-7 Kernel:tian vmalloc_limit (PHY) =0x2f800000, Vmalloc_min (VA) =0xef800000, vmalloc_start=0x800000, vmalloc_end=0xff000000, 00:00:03 xx-b-7 Kernel:tian bank[0]. size=534773760, Bank[0].highmem=0, Bank[0].start (PHY) =0x0, 00:00:03 xx-b-7 kernel:tian Config_highmem defined, NR_ banks=8 Jan 00:00:03 xx-b-7 Kernel:tian bank[1].size=2080374784, Bank[0].highmem=1, Bank[1].start (PHY) =0x1 Jan 01 00:0 0:03 xx-b-7 Kernel:tian Config_highmem defined, nr_banks=8, 00:00:03 xx-b-7 Kernel:tian high_memory_0 (VA) =0xdfe000 XX, (PHY) 0x1fe00000; High_mEmory_1 (VA) =0xdfdfffff, (PHY) 0x1fdfffff Jan 00:00:03 xx-b-7 Kernel:tian meminfo.nr_banks=2, high_memory (VA) = 0xdfe00000 Jan 00:00:03 xx-b-7 kernel:tian Virtual kernel memory Layout:tian vector:0xffff0000-0xffff1000 (4 KB) TIAN fixmap:0xfff00000-0xfffe0000 (896 KB) TIAN vmalloc:0xe0000000-0xff000000 (496 MB) TIAN Lowmem: 0xc0000000-0xdfe00000 (510 MB) TIAN pkmap:0xbfe00000-0xc0000000 (2 MB) TIAN modules:0xbf800000-0xbfe00000 (6 MB) TIAN. t EXT:0XC0008000-0XC0376AA4 (3515 KB) TIAN. INIT:0XC0377000-0XC03F73C0 (513 kb) TIAN. data:0xc03f8000-0xc044795 0 (319 KB) TIAN. Bss:0xc0447950-0xc04b8ee4 (454 kb) TIAN arm_lowmem_limit=0x1fe00000, high_memory=0xdfe00000