Re: [PATCH] x86, mtrr: mark range_new in mtrr_calc_range_state() as __initdata

From: Ingo Molnar
Date: Fri Nov 27 2015 - 04:31:40 EST



* Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx> wrote:

> range_new doesn't seem to be used after init. It is only passed to
> memset, sum_ranges, memcmp and x86_get_mtrr_mem_range, the latter of
> which also only passes it on to various *range* library functions. So
> mark it __initdata to free up an extra page after init.
>
> nr_range_new is unconditionally assigned to before it is read, so
> there's no point in having it static.
>
> Signed-off-by: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
> ---
> arch/x86/kernel/cpu/mtrr/cleanup.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kernel/cpu/mtrr/cleanup.c b/arch/x86/kernel/cpu/mtrr/cleanup.c
> index 70d7c93f4550..b1a9ad366f67 100644
> --- a/arch/x86/kernel/cpu/mtrr/cleanup.c
> +++ b/arch/x86/kernel/cpu/mtrr/cleanup.c
> @@ -593,9 +593,9 @@ mtrr_calc_range_state(u64 chunk_size, u64 gran_size,
> unsigned long x_remove_base,
> unsigned long x_remove_size, int i)
> {
> - static struct range range_new[RANGE_NUM];
> + static struct range range_new[RANGE_NUM] __initdata;
> unsigned long range_sums_new;
> - static int nr_range_new;
> + int nr_range_new;
> int num_reg;
>
> /* Convert ranges to var ranges state: */

So this static variable actually surprised me - I never realized it was there -
and it's not some simple 'once' flag, but something that is essential semantics.

So marking it __initdata is correct, but please also move it out of function local
variables scope, into file scope - and name it properly as well, like
mtrr_new_range[] or so?

Thanks,

Ingo
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/