Messages in this thread | | | From | Geert Uytterhoeven <> | Date | Thu, 6 Feb 2020 18:20:15 +0100 | Subject | Re: [for-next][PATCH 04/26] bootconfig: Add Extra Boot Config support |
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Hi Hiramatsu-san,
On Thu, Feb 6, 2020 at 3:42 PM Masami Hiramatsu <mhiramat@kernel.org> wrote: > On Thu, 6 Feb 2020 12:54:05 +0100 > Borislav Petkov <bp@alien8.de> wrote: > > On Tue, Jan 14, 2020 at 04:03:20PM -0500, Steven Rostedt wrote: > > > diff --git a/init/Kconfig b/init/Kconfig > > > index a34064a031a5..63450d3bbf12 100644 > > > --- a/init/Kconfig > > > +++ b/init/Kconfig > > > @@ -1215,6 +1215,17 @@ source "usr/Kconfig" > > > > > > endif > > > > > > +config BOOT_CONFIG > > > + bool "Boot config support" > > > + select LIBXBC > > > + default y > > > > Any particular reason this is default y? Why should it be enabled by > > default on all boxes? > > Oh, you are not the first person asked that :) > > https://lkml.org/lkml/2019/12/9/563 > > And yes, I think this is important that will useful for most developers > and admins. Since the bootconfig already covers kernel and init options, > this can be a new standard way to pass args to kernel boot. > > And as I reported above thread, the memory footpoint of view, most code > and working memory are released after boot. Also, as Linus's suggested, > now this feature is enabled only if user gives "bootconfig" on the kernel > command line. So the side effect is minimized.
With m68k/atari_defconfig, bloat-o-meter says:
add/remove: 39/0 grow/shrink: 2/0 up/down: 13086/0 (13086)
which is IMHO not that small for a "default y" option that may or may not be used.
Especially:
Function old new delta xbc_nodes - 8192 +8192
Any chance xbc_nodes can be allocated dynamically, and only when needed?
Yes, there are industrial products running Linux on a current ARM SoC using the builtin 8 or 10 MiB of SRAM (+ XIP for the kernel), so these definitely want to say CONFIG_BOOT_CONFIG=n.
Thanks!
add/remove: 39/0 grow/shrink: 2/0 up/down: 13086/0 (13086) Function old new delta xbc_nodes - 8192 +8192 xbc_init - 854 +854 start_kernel 1020 1580 +560 copy_xbc_key_value_list - 362 +362 __xbc_parse_value - 324 +324 xbc_snprint_cmdline - 294 +294 xbc_node_compose_key_after - 266 +266 xbc_namebuf - 256 +256 xbc_add_sibling - 254 +254 xbc_node_find_next_leaf - 186 +186 xbc_node_find_child - 176 +176 __xbc_add_key - 162 +162 proc_boot_config_init - 124 +124 xbc_make_cmdline - 122 +122 xbc_node_find_value - 104 +104 xbc_node_find_next_key_value - 102 +102 __xbc_close_brace - 92 +92 find_match_node - 80 +80 __xbc_parse_keys - 78 +78 xbc_node_get_data - 64 +64 xbc_parse_key - 60 +60 skip_comment - 48 +48 xbc_destroy_all - 42 +42 xbc_node_get_parent - 38 +38 xbc_parse_error - 36 +36 xbc_node_get_child - 34 +34 xbc_node_get_next - 32 +32 boot_config_checksum - 30 +30 boot_config_proc_show - 26 +26 xbc_root_node - 20 +20 kzalloc.constprop 810 830 +20 xbc_node_index - 14 +14 xbc_node_num - 4 +4 xbc_data_size - 4 +4 xbc_data - 4 +4 saved_boot_config - 4 +4 last_parent - 4 +4 extra_init_args - 4 +4 extra_command_line - 4 +4 __initcall_proc_boot_config_init5 - 4 +4 xbc_debug_dump - 2 +2 Total: Before=3688860, After=3701946, chg +0.35%
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
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