[Intel-gfx] [PATCH v6 25/57] drm_print: wrap drm_*_dbg in dyndbg descriptor factory macro

Jim Cromie
2022-09-04T21:46:26Z

For CONFIG_DRM_USE_DYNAMIC_DEBUG=y, wrap __drm_dbg() & __drm_dev_dbg()
in one of dyndbg's Factory macros: _dynamic_func_call_no_desc().

This adds the callsite descriptor into the code, and an entry for each
into /proc/dynamic_debug/control.

#> echo class DRM_UT_ATOMIC +p > /proc/dynamic_debug/control

CONFIG_DRM_USE_DYNAMIC_DEBUG=y/n is configurable because of the .data
footprint cost of per-callsite control; 56 bytes/site * ~2k for i915,
~4k callsites for amdgpu. This is large enough that a kernel builder
might not want it.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
drivers/gpu/drm/Kconfig | 12 ++++++++++++
drivers/gpu/drm/Makefile | 2 ++
include/drm/drm_print.h | 12 ++++++++++++
3 files changed, 26 insertions(+)

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 2f52e8941074..3b75c286f14f 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -51,6 +51,18 @@ config DRM_DEBUG_MM

If in doubt, say "N".

+config DRM_USE_DYNAMIC_DEBUG
+ bool "use dynamic debug to implement drm.debug"
+ default y
+ depends on DRM
+ depends on DYNAMIC_DEBUG || DYNAMIC_DEBUG_CORE
+ depends on JUMP_LABEL
+ help
+ Use dynamic-debug to avoid drm_debug_enabled() runtime overheads.
+ Due to callsite counts in DRM drivers (~4k in amdgpu) and 56
+ bytes per callsite, the .data costs can be substantial, and
+ are therefore configurable.
+
config DRM_KUNIT_TEST
tristate "KUnit tests for DRM" if !KUNIT_ALL_TESTS
depends on DRM && KUNIT
diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
index 25d0ba310509..0b283e46f28b 100644
--- a/drivers/gpu/drm/Makefile
+++ b/drivers/gpu/drm/Makefile
@@ -3,6 +3,8 @@
# Makefile for the drm device driver. This driver provides support for the
# Direct Rendering Infrastructure (DRI) in XFree86 4.1.0 and higher.

+CFLAGS-$(CONFIG_DRM_USE_DYNAMIC_DEBUG) += -DDYNAMIC_DEBUG_MODULE
+
drm-y := drm_aperture.o drm_auth.o drm_cache.o \
drm_file.o drm_gem.o drm_ioctl.o \
drm_drv.o \
diff --git a/include/drm/drm_print.h b/include/drm/drm_print.h
index c429c258c957..2d2cef76b5c1 100644
--- a/include/drm/drm_print.h
+++ b/include/drm/drm_print.h
@@ -384,8 +384,14 @@ void __drm_dev_dbg(const struct device *dev, enum drm_debug_category category,
} \
})

+#if !defined(CONFIG_DRM_USE_DYNAMIC_DEBUG)
#define drm_dev_dbg(dev, cat, fmt, ...) \
__drm_dev_dbg(dev, cat, fmt, ##__VA_ARGS__)
+#else
+#define drm_dev_dbg(dev, cat, fmt, ...) \
+ _dynamic_func_call_no_desc(fmt, __drm_dev_dbg, \
+ dev, cat, fmt, ##__VA_ARGS__)
+#endif

/**
* DRM_DEV_DEBUG() - Debug output for generic drm code
@@ -492,7 +498,13 @@ 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(cat, fmt, ...) \
+ _dynamic_func_call_no_desc(fmt, ___drm_dbg, \
+ cat, fmt, ##__VA_ARGS__)
+#endif

/* Macros to make printk easier */

--
2.37.2