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But it doesn't until CONFIG_MEMORY_HOTPLUG not set >> neither. > >When CONFIG_ARCH_KEEP_MEMBLOCK is not set memblock information both for >normal and reserved memory get freed up but should the memblock related >code and data also be freed up as well ? Then I would also believe such If not freed, those functions would access unpredictable area. >memory saving will be very minimal given CONFIG_ARCH_KEEP_MEMBLOCK code >is too limited scoped in the tree. Not very much, it shows 12K more in it. > >Also could you please explain how it is related to CONFIG_MEMORY_HOTPLUG >config being set or not. > This is in file include/asm-generic/vmlinux.lds.h. MEM_KEEP/MEM_DISCARD is conditionally defined by CONFIG_MEMORY_HOTPLUG. So even __init_memblock is defined as __meminit when CONFIG_ARCH_KEEP_MEMBLOCK not set, it is not discarded. >> >> This patch puts memblock's .text/.data into its own section, so that it >> only depends on CONFIG_ARCH_KEEP_MEMBLOCK to discard related code and >> data. After this, init size increase from 2420K to 2432K. > >Is not this memory size saving some what insignificant to warrant a code >change ? Also is this problem applicable only to CONFIG_ARCH_KEEP_MEMBLOCK Yes, this is not significant. >config. Could you also provide details on how did you measure these numbers ? > Kernel print related info in mem_init_print_info(). One of is it init size, which includes init_data and init_text. >> >> Signed-off-by: Wei Yang >> --- >> include/asm-generic/vmlinux.lds.h | 14 +++++++++++++- >> include/linux/memblock.h | 8 ++++---- >> 2 files changed, 17 insertions(+), 5 deletions(-) >> >> diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h >> index f7749d0f2562..775c5eedb9e6 100644 >> --- a/include/asm-generic/vmlinux.lds.h >> +++ b/include/asm-generic/vmlinux.lds.h >> @@ -147,6 +147,14 @@ >> #define MEM_DISCARD(sec) *(.mem##sec) >> #endif >> >> +#if defined(CONFIG_ARCH_KEEP_MEMBLOCK) >> +#define MEMBLOCK_KEEP(sec) *(.mb##sec) >> +#define MEMBLOCK_DISCARD(sec) >> +#else >> +#define MEMBLOCK_KEEP(sec) >> +#define MEMBLOCK_DISCARD(sec) *(.mb##sec) >> +#endif >> + >> #ifndef CONFIG_HAVE_DYNAMIC_FTRACE_NO_PATCHABLE >> #define KEEP_PATCHABLE KEEP(*(__patchable_function_entries)) >> #define PATCHABLE_DISCARDS >> @@ -356,6 +364,7 @@ >> *(.ref.data) \ >> *(.data..shared_aligned) /* percpu related */ \ >> MEM_KEEP(init.data*) \ >> + MEMBLOCK_KEEP(init.data*) \ >> *(.data.unlikely) \ >> __start_once = .; \ >> *(.data.once) \ >> @@ -573,6 +582,7 @@ >> *(.ref.text) \ >> *(.text.asan.* .text.tsan.*) \ >> MEM_KEEP(init.text*) \ >> + MEMBLOCK_KEEP(init.text*) \ >> >> >> /* sched.text is aling to function alignment to secure we have same >> @@ -680,6 +690,7 @@ >> KEEP(*(SORT(___kentry+*))) \ >> *(.init.data .init.data.*) \ >> MEM_DISCARD(init.data*) \ >> + MEMBLOCK_DISCARD(init.data*) \ >> KERNEL_CTORS() \ >> MCOUNT_REC() \ >> *(.init.rodata .init.rodata.*) \ >> @@ -706,7 +717,8 @@ >> #define INIT_TEXT \ >> *(.init.text .init.text.*) \ >> *(.text.startup) \ >> - MEM_DISCARD(init.text*) >> + MEM_DISCARD(init.text*) \ >> + MEMBLOCK_DISCARD(init.text*) >> >> #define EXIT_DATA \ >> *(.exit.data .exit.data.*) \ >> diff --git a/include/linux/memblock.h b/include/linux/memblock.h >> index e2082240586d..3e1f1d42dde7 100644 >> --- a/include/linux/memblock.h >> +++ b/include/linux/memblock.h >> @@ -100,13 +100,13 @@ struct memblock { >> >> extern struct memblock memblock; >> >> +#define __init_memblock __section(".mbinit.text") __cold notrace \ >> + __latent_entropy >> +#define __initdata_memblock __section(".mbinit.data") >> + >> #ifndef CONFIG_ARCH_KEEP_MEMBLOCK >> -#define __init_memblock __meminit >> -#define __initdata_memblock __meminitdata >> void memblock_discard(void); >> #else >> -#define __init_memblock >> -#define __initdata_memblock >> static inline void memblock_discard(void) {} >> #endif >> -- Wei Yang Help you, Help me