In the logging code, we are currently checking is we need to output in drm_ut_debug_printk(). This is too late. The problem is that when we write something like:
DRM_DEBUG_DRIVER("ELD on [CONNECTOR:%d:%s], [ENCODER:%d:%s]\n", connector->base.id, drm_get_connector_name(connector), connector->encoder->base.id, drm_get_encoder_name(connector->encoder));
We start by evaluating the arguments (so call drm_get_connector_name() and drm_get_connector_name()) before ending up in drm_ut_debug_printk() which will then does nothing.
This means we execute a lot of instructions (drm_get_connector_name(), in turn, calls snprintf() for example) to happily discard them in the normal case, drm.debug=0.
So, let's put the test on drm_debug earlier, in the macros themselves. Sprinkle an unlikely() as well for good measure.
Signed-off-by: Damien Lespiau damien.lespiau@intel.com --- drivers/gpu/drm/drm_stub.c | 26 ++++++++++++-------------- include/drm/drmP.h | 27 +++++++++++++++------------ 2 files changed, 27 insertions(+), 26 deletions(-)
diff --git a/drivers/gpu/drm/drm_stub.c b/drivers/gpu/drm/drm_stub.c index dc2c609..81ed832 100644 --- a/drivers/gpu/drm/drm_stub.c +++ b/drivers/gpu/drm/drm_stub.c @@ -97,26 +97,24 @@ int drm_err(const char *func, const char *format, ...) } EXPORT_SYMBOL(drm_err);
-void drm_ut_debug_printk(unsigned int request_level, - const char *prefix, +void drm_ut_debug_printk(const char *prefix, const char *function_name, const char *format, ...) { struct va_format vaf; va_list args;
- if (drm_debug & request_level) { - va_start(args, format); - vaf.fmt = format; - vaf.va = &args; - - if (function_name) - printk(KERN_DEBUG "[%s:%s], %pV", prefix, - function_name, &vaf); - else - printk(KERN_DEBUG "%pV", &vaf); - va_end(args); - } + va_start(args, format); + vaf.fmt = format; + vaf.va = &args; + + if (function_name) + printk(KERN_DEBUG "[%s:%s], %pV", prefix, + function_name, &vaf); + else + printk(KERN_DEBUG "%pV", &vaf); + + va_end(args); } EXPORT_SYMBOL(drm_ut_debug_printk);
diff --git a/include/drm/drmP.h b/include/drm/drmP.h index 3055b36..87b558a 100644 --- a/include/drm/drmP.h +++ b/include/drm/drmP.h @@ -121,9 +121,8 @@ struct videomode; #define DRM_UT_KMS 0x04 #define DRM_UT_PRIME 0x08
-extern __printf(4, 5) -void drm_ut_debug_printk(unsigned int request_level, - const char *prefix, +extern __printf(3, 4) +void drm_ut_debug_printk(const char *prefix, const char *function_name, const char *format, ...); extern __printf(2, 3) @@ -209,24 +208,28 @@ int drm_err(const char *func, const char *format, ...); #if DRM_DEBUG_CODE #define DRM_DEBUG(fmt, args...) \ do { \ - drm_ut_debug_printk(DRM_UT_CORE, DRM_NAME, \ - __func__, fmt, ##args); \ + if (unlikely(drm_debug & DRM_UT_CORE)) \ + drm_ut_debug_printk(DRM_NAME, __func__, \ + fmt, ##args); \ } while (0)
#define DRM_DEBUG_DRIVER(fmt, args...) \ do { \ - drm_ut_debug_printk(DRM_UT_DRIVER, DRM_NAME, \ - __func__, fmt, ##args); \ + if (unlikely(drm_debug & DRM_UT_DRIVER)) \ + drm_ut_debug_printk(DRM_NAME, __func__, \ + fmt, ##args); \ } while (0) -#define DRM_DEBUG_KMS(fmt, args...) \ +#define DRM_DEBUG_KMS(fmt, args...) \ do { \ - drm_ut_debug_printk(DRM_UT_KMS, DRM_NAME, \ - __func__, fmt, ##args); \ + if (unlikely(drm_debug & DRM_UT_KMS)) \ + drm_ut_debug_printk(DRM_NAME, __func__, \ + fmt, ##args); \ } while (0) #define DRM_DEBUG_PRIME(fmt, args...) \ do { \ - drm_ut_debug_printk(DRM_UT_PRIME, DRM_NAME, \ - __func__, fmt, ##args); \ + if (unlikely(drm_debug & DRM_UT_PRIME)) \ + drm_ut_debug_printk(DRM_NAME, __func__, \ + fmt, ##args); \ } while (0) #else #define DRM_DEBUG_DRIVER(fmt, args...) do { } while (0)