Change __drm_dbg() macro to be CONFIG_DRM_USE_DYNAMIC_DEBUG dependent: N- keep straight mapping to exported ___drm_dbg() Y- wrap ___drm_dbg() inside _dynamic_func_call_no_desc()
This patch places ~1/2 of drm.debug API messages behind dyndbg's JUMP_LABEL/NOOP optimization.
The CONFIG_DRM_USE_DYNAMIC_DEBUG dependence is due to the .data footprint cost of per-callsite control; 56 bytes/site * ~2k,3k callsites (for i915, amdgpu), which is significant enough to make optional.
bash-5.1# drms_load [ 7.489844] dyndbg: 239 debug prints in module drm [ 7.494010] ACPI: bus type drm_connector registered [ 7.546076] dyndbg: 81 debug prints in module drm_kms_helper [ 7.555723] dyndbg: 2 debug prints in module ttm [ 7.558920] dyndbg: 8 debug prints in module video [ 8.074699] dyndbg: 431 debug prints in module i915 [ 8.158682] AMD-Vi: AMD IOMMUv2 functionality not available on this system - This is not a bug. [ 8.574456] dyndbg: 3817 debug prints in module amdgpu [ 8.589962] [drm] amdgpu kernel modesetting enabled. [ 8.590548] amdgpu: CRAT table not found [ 8.590998] amdgpu: Virtual CRAT table created for CPU [ 8.591634] amdgpu: Topology: Add CPU node [ 8.636446] dyndbg: 3 debug prints in module wmi [ 8.768667] dyndbg: 24 debug prints in module nouveau
Signed-off-by: Jim Cromie jim.cromie@gmail.com --- include/drm/drm_print.h | 34 +++++++++++++++++++++++++++++++++- 1 file changed, 33 insertions(+), 1 deletion(-)
diff --git a/include/drm/drm_print.h b/include/drm/drm_print.h index 1eef315a0a65..8d6b74270c50 100644 --- a/include/drm/drm_print.h +++ b/include/drm/drm_print.h @@ -319,10 +319,36 @@ enum drm_debug_category { DRM_UT_DRMRES };
+/* + * 3 name flavors of drm_debug_enabled: + * drm_debug_enabled - public/legacy, always checks bits + * _drm_debug_enabled - instrumented to observe call-rates, est overheads. + * __drm_debug_enabled - privileged - knows jump-label state, can short-circuit + */ static inline bool drm_debug_enabled(enum drm_debug_category category) { return unlikely(__drm_debug & BIT(category)); } +/* + * Wrap fn in macro, so that the pr_debug sees the actual caller, not + * the inline fn. Using this name creates a callsite entry / control + * point in /proc/dynamic_debug/control. + */ +#define _drm_debug_enabled(category) \ + ({ \ + pr_debug("todo: maybe avoid via dyndbg\n"); \ + drm_debug_enabled(category); \ + }) +#if defined(CONFIG_DRM_USE_DYNAMIC_DEBUG) +/* + * dyndbg is wrapping the drm.debug API, so as to avoid the runtime + * bit-test overheads of drm_debug_enabled() in those api calls. + * In this case, executed callsites are known enabled, so true. + */ +#define __drm_debug_enabled(category) true +#else +#define __drm_debug_enabled(category) drm_debug_enabled(category) +#endif
/* * struct device based logging @@ -497,7 +523,13 @@ void ___drm_dbg(enum drm_debug_category category, const char *format, ...); __printf(1, 2) void __drm_err(const char *format, ...);
+#if !defined(CONFIG_DRM_USE_DYNAMIC_DEBUG) #define __drm_dbg(fmt, ...) ___drm_dbg(fmt, ##__VA_ARGS__) +#else +#define __drm_dbg(eCat, fmt, ...) \ + _dynamic_func_call_no_desc(fmt, ___drm_dbg, \ + eCat, fmt, ##__VA_ARGS__) +#endif
/* Macros to make printk easier */
@@ -569,7 +601,7 @@ void __drm_err(const char *format, ...); static DEFINE_RATELIMIT_STATE(rs_, DEFAULT_RATELIMIT_INTERVAL, DEFAULT_RATELIMIT_BURST);\ const struct drm_device *drm_ = (drm); \ \ - if (drm_debug_enabled(DRM_UT_ ## category) && __ratelimit(&rs_)) \ + if (__drm_debug_enabled(DRM_UT_ ## category) && __ratelimit(&rs_)) \ drm_dev_printk(drm_ ? drm_->dev : NULL, KERN_DEBUG, fmt, ## __VA_ARGS__); \ })