On 2023/3/24 21:18, Baoquan He wrote:
> After taking off the protection functions on crashkernel memory region,
> there's no need to map crashkernel region with page granularity during
> linear mapping.
>
> With this change, the system can make use of block or section mapping
> on linear region to largely improve perforcemence during system bootup
> and running.
>
> Signed-off-by: Baoquan He <bhe@xxxxxxxxxx>
> ---
> arch/arm64/mm/mmu.c | 43 -------------------------------------------
> 1 file changed, 43 deletions(-)
>
> diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
> index 6f9d8898a025..7556020a27b7 100644
> --- a/arch/arm64/mm/mmu.c
> +++ b/arch/arm64/mm/mmu.c
> @@ -510,21 +510,6 @@ void __init mark_linear_text_alias_ro(void)
> PAGE_KERNEL_RO);
> }
>
> -static bool crash_mem_map __initdata;
> -
> -static int __init enable_crash_mem_map(char *arg)
> -{
> - /*
> - * Proper parameter parsing is done by reserve_crashkernel(). We only
> - * need to know if the linear map has to avoid block mappings so that
> - * the crashkernel reservations can be unmapped later.
> - */
> - crash_mem_map = true;
> -
> - return 0;
> -}
> -early_param("crashkernel", enable_crash_mem_map);
> -
> static void __init map_mem(pgd_t *pgdp)
> {
> static const u64 direct_map_end = _PAGE_END(VA_BITS_MIN);
> @@ -554,16 +539,6 @@ static void __init map_mem(pgd_t *pgdp)
> */
> memblock_mark_nomap(kernel_start, kernel_end - kernel_start);
>
> -#ifdef CONFIG_KEXEC_CORE
> - if (crash_mem_map) {
> - if (defer_reserve_crashkernel())
> - flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;
> - else if (crashk_res.end)
> - memblock_mark_nomap(crashk_res.start,
> - resource_size(&crashk_res));
> - }
> -#endif
> -
> /* map all the memory banks */
> for_each_mem_range(i, &start, &end) {
> if (start >= end)
> @@ -590,24 +565,6 @@ static void __init map_mem(pgd_t *pgdp)
> __map_memblock(pgdp, kernel_start, kernel_end,
> PAGE_KERNEL, NO_CONT_MAPPINGS);
> memblock_clear_nomap(kernel_start, kernel_end - kernel_start);
> -
> - /*
> - * Use page-level mappings here so that we can shrink the region
> - * in page granularity and put back unused memory to buddy system
> - * through /sys/kernel/kexec_crash_size interface.
> - */
> -#ifdef CONFIG_KEXEC_CORE
> - if (crash_mem_map && !defer_reserve_crashkernel()) {
> - if (crashk_res.end) {
> - __map_memblock(pgdp, crashk_res.start,
> - crashk_res.end + 1,
> - PAGE_KERNEL,
> - NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS);
> - memblock_clear_nomap(crashk_res.start,
> - resource_size(&crashk_res));
> - }
> - }
> -#endif
> }
>
> void mark_rodata_ro(void)
>
Reviewed-by: Zhen Lei <thunder.leizhen@xxxxxxxxxx>
--
Regards,
Zhen Lei
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