Re: [PATCH v2] x86/setup: Merge {early_,}reserve_initrd() to one function

From: Ingo Molnar
Date: Tue Feb 09 2016 - 04:16:39 EST



* Alexander Kuleshov <kuleshovmail@xxxxxxxxx> wrote:

> The check and definitions related to ramdisk are similar in the
> early_reserve_initrd() and reserve_initrd(). So we can get rid of
> early_reserve_initrd() and and use late or early algorithm for
> initrd reservation depends on reserve_initrd() parameter value.
>
> Save 396 bytes of code:
>
> text data bss dec hex filename
> 9281618 5010736 15474688 29767042 1c63582 vmlinux.orig
>
> text data bss dec hex filename
> 9281222 5010672 15474688 29766582 1c633b6 vmlinux.new
>
> Signed-off-by: Alexander Kuleshov <kuleshovmail@xxxxxxxxx>
> ---
> Changelog:
>
> v2: parameter of reserve_initrd() - int -> bool.
> commit message updated.
>
> arch/x86/kernel/setup.c | 29 +++++++++--------------------
> 1 file changed, 9 insertions(+), 20 deletions(-)
>
> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> index d3d80e6..0a2fa55 100644
> --- a/arch/x86/kernel/setup.c
> +++ b/arch/x86/kernel/setup.c
> @@ -349,20 +349,7 @@ static void __init relocate_initrd(void)
> relocated_ramdisk, relocated_ramdisk + ramdisk_size - 1);
> }
>
> -static void __init early_reserve_initrd(void)
> -{
> - /* Assume only end is not page aligned */
> - u64 ramdisk_image = get_ramdisk_image();
> - u64 ramdisk_size = get_ramdisk_size();
> - u64 ramdisk_end = PAGE_ALIGN(ramdisk_image + ramdisk_size);
> -
> - if (!boot_params.hdr.type_of_loader ||
> - !ramdisk_image || !ramdisk_size)
> - return; /* No initrd provided by bootloader */
> -
> - memblock_reserve(ramdisk_image, ramdisk_end - ramdisk_image);
> -}
> -static void __init reserve_initrd(void)
> +static void __init reserve_initrd(bool early)
> {
> /* Assume only end is not page aligned */
> u64 ramdisk_image = get_ramdisk_image();
> @@ -374,6 +361,11 @@ static void __init reserve_initrd(void)
> !ramdisk_image || !ramdisk_size)
> return; /* No initrd provided by bootloader */
>
> + if (early) {
> + memblock_reserve(ramdisk_image, ramdisk_end - ramdisk_image);
> + return;
> + }
> +
> initrd_start = 0;
>
> mapped_size = memblock_mem_size(max_pfn_mapped);
> @@ -398,10 +390,7 @@ static void __init reserve_initrd(void)
> memblock_free(ramdisk_image, ramdisk_end - ramdisk_image);
> }
> #else
> -static void __init early_reserve_initrd(void)
> -{
> -}
> -static void __init reserve_initrd(void)
> +static void __init reserve_initrd(bool early)
> {
> }
> #endif /* CONFIG_BLK_DEV_INITRD */
> @@ -850,7 +839,7 @@ void __init setup_arch(char **cmdline_p)
> memblock_reserve(__pa_symbol(_text),
> (unsigned long)__bss_stop - (unsigned long)_text);
>
> - early_reserve_initrd();
> + reserve_initrd(true);
>
> /*
> * At this point everything still needed from the boot loader
> @@ -1135,7 +1124,7 @@ void __init setup_arch(char **cmdline_p)
> /* Allocate bigger log buffer */
> setup_log_buf(1);
>
> - reserve_initrd();
> + reserve_initrd(false);
>
> #if defined(CONFIG_ACPI) && defined(CONFIG_BLK_DEV_INITRD)
> acpi_initrd_override((void *)initrd_start, initrd_end - initrd_start);

So I don't think the code got easier to understand - in particular the
memblock_reserve()/free() pattern, depending on a flag value, is confusing.

The duplication is there - but please factor it out into a helper structure
('struct ramdisk') and a helper function that sets up the structure.

Thanks,

Ingo