Hi Greg, Jason, Please consider these for char/misc or linux-next/soon/mumble. This patchset adds exclusive class support to dyndbg, allowing it to directly represent drm's debug_category. It is the dyndbg half of: https://lore.kernel.org/lkml/20220217034829.64395-1-jim.cromie@xxxxxxxxx/ The DRM half of that patchset uses this support to reimplement drm.debug on dyndbg, and uses its callsite patching to avoid the runtime checking done by drm_debug_enabled(). Background: In the past, various extensions to dyndbg/pr_debug have been proposed, none seemed to gain any consensus. This list is certainly incomplete. https://lore.kernel.org/lkml/20200609104604.1594-1-stanimir.varbanov@xxxxxxxxxx/ pr_levels was discussed around this patchset, in revs 3,4,5 This search helps: s:venus: s:dynamic f:stanimir.varbanov@xxxxxxxxxx IMO, pr_levels suffers from implied meaning between the levels: 2 > 1. In contrast, DRM has logically disjoint categories, and is implemented in an enum (despite its flag/mask values, a micro-optimization). https://lore.kernel.org/lkml/20210813151734.1236324-1-jim.cromie@xxxxxxxxx/ That patchset used pr_debug in DRM, and prepended "drm:kms:" etc to the format strings so each category was selectable; "format drm:kms:" in the query. This worked, but it made the format config-dependent, and was hard to explain without undue "artifact". So this patchset adds .class_id field (4-bits) to dynamic-debug callsites, and 'class N' query/command support to select upon it. Existing callsites and queries get .class_id=15, so 0-14 are available for use by the client (DRM wants 0-10). The DRM patchset then: . renumbers drm_debug_category to fit into the 4-bit .class_id the new enumerations *are* the bit-positions in drm/parameters/debug. . adapts the category-macro layer to use _CLS macros, mapping categories. . adds macro layer under the category-macro layer which wraps drm_*dbg inside a dyndbg Factory macro . uses DEFINE_DYNAMIC_DEBUG_CLASSBITS to tie to __drm_debug callbacks ref the var, so drm_debug_enabled(cat) just works. Jim Cromie (5): dyndbg: fix static_branch manipulation fixes a latent bug, before a 2nd "enable" flag exposes it. dyndbg: add class_id field and query support will allow (with that drm patchset): #> # turn on DRM_ATOMIC in amdgpu #> echo module amdgpu class 4 +p > /proc/dynamic_debug/control #> # turn on DRM_CORE in drm #> echo module drm class 0 +p > /proc/dynamic_debug/control dyndbg: add DEFINE_DYNAMIC_DEBUG_CLASSBITS macro adds macro & callbacks to support drm.debug bitmap #> echo 4 > /sys/module/drm/parameters/debug dyndbg: drop EXPORTed dynamic_debug_exec_queries unused yet, obsoleted by 2,3 dyndbg: show both old and new in change-info minor debug improvement .../admin-guide/dynamic-debug-howto.rst | 7 + include/linux/dynamic_debug.h | 111 ++++++++++--- lib/dynamic_debug.c | 150 ++++++++++++++---- 3 files changed, 213 insertions(+), 55 deletions(-) -- 2.35.1
