On Thu, Mar 15, 2018 at 08:17:53AM -0700, Joe Perches wrote:
On Thu, 2018-03-15 at 17:05 +0200, Ville Syrjälä wrote:
On Thu, Mar 15, 2018 at 03:04:52PM +0100, Maarten Lankhorst wrote:
Op 15-03-18 om 14:30 schreef Ville Syrjälä:
On Tue, Mar 13, 2018 at 03:02:15PM -0700, Joe Perches wrote:
drm_printk is used for both DRM_ERROR and DRM_DEBUG with unnecessary arguments that can be removed by creating separate functins.
Create specific functions for these calls to reduce x86/64 defconfig size by ~20k.
Modify the existing macros to use the specific calls.
new: $ size -t drivers/gpu/drm/built-in.a | tail -1 1876562 44542 995 1922099 1d5433 (TOTALS)
old: $ size -t drivers/gpu/drm/built-in.a | tail -1 1897565 44542 995 1943102 1da63e (TOTALS)
Miscellanea:
o intel_display requires a change to use the specific calls.
How much would we lose if we move the (drm_debug&FOO) outside the functions again?
again?
We used to do that. Someone changed it a while back, unintentially I believe.
I'm somewhat concerned about all the function call overhead when debugs aren't even enabled.
Perhaps better to have compilation elimination of the entire debug output instead.
That would require every bug reporter to recompile the kernel first. So this is not a solution we would ever seriously consider.
Not sure if it would be possible to use the alternatives thing to eliminate the function calls unless the user boots wih drm.debug!=0?
I think you are discussing a different issue and this discussion should not block this patch as this patch has no impact other than code size reduction.
But what is the goal of the code size reduction? I assume the main goal is to make better use of the instruction cache to make the code faster. If there's a tradeoff between smaller and slightly faster vs. larger and a singificantly faster I tend to think we should go for the latter option.