diff options
author | Rasmus Villemoes <[email protected]> | 2015-12-01 21:44:50 +0100 |
---|---|---|
committer | Ingo Molnar <[email protected]> | 2015-12-04 09:11:28 +0100 |
commit | c332813b51cbe807d539bb059b81235abf1e3fdd (patch) | |
tree | 6cdca0850c8f281fe95bb30c54dc75620c9fed34 | |
parent | 8609d1b5daa36350e020e737946c40887af1743a (diff) |
x86/mm/mtrr: Mark the 'range_new' static variable in mtrr_calc_range_state() as __initdata
'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.
Its contents are wiped at every call to mtrr_calc_range_state(),
so it being static is not about preserving state between calls,
but simply to avoid a 4k+ stack frame. While there, add a
comment explaining this and why it's safe.
We could also mark nr_range_new as __initdata, but since it's
just a single int and also doesn't carry state between calls (it
is unconditionally assigned to before it is read), we might as
well make it an ordinary automatic variable.
Signed-off-by: Rasmus Villemoes <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Toshi Kani <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
-rw-r--r-- | arch/x86/kernel/cpu/mtrr/cleanup.c | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/arch/x86/kernel/cpu/mtrr/cleanup.c b/arch/x86/kernel/cpu/mtrr/cleanup.c index 70d7c93f4550..0d98503c2245 100644 --- a/arch/x86/kernel/cpu/mtrr/cleanup.c +++ b/arch/x86/kernel/cpu/mtrr/cleanup.c @@ -593,9 +593,16 @@ 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]; + /* + * range_new should really be an automatic variable, but + * putting 4096 bytes on the stack is frowned upon, to put it + * mildly. It is safe to make it a static __initdata variable, + * since mtrr_calc_range_state is only called during init and + * there's no way it will call itself recursively. + */ + 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: */ |