hi Jason, Greg, Daniel, DRM-everyone
drm.debug api provides ~23 macros to issue 10 categories of debug messages, each enabled by a bit in /sys/module/drm/parameters/debug. drm_debug_enabled(category) tests these bits at runtime; while cheap individually, the costs accumulate.
Daniel, I think this revision addresses most of your early review, a lot has changed since. Heres the link: https://patchwork.freedesktop.org/patch/443989/
For CONFIG_DRM_USE_DYNAMIC_DEBUG=y, this patchset obsoletes those runtime tests (inside drm_*dbg) by wrapping the 2 fns in one of the dynamic_func_call* Factory macros. The config dependence is due to the .data footprint cost of the tables; AMDGPU has ~4k callsites, at 56 bytes each.
This patchset creates entries in /proc/dynamic_debug/control for each callsite, and each has .class_id = macros' category. Those entries, and a new query keyword, allow (1st):
# 1=DRM_UT_KMS (iirc) #> echo "module drm class 1 +p > /proc/dynamic_debug/control
Then equivalently: # except it also clears other flags #> echo 0x01 > /sys/module/drm/parameters/debug
series overview:
dyndbg: - fix a bug in dyndbg static_key toggling, @stable cc'd - adds support for distinct classes to dyndbg (new,unused feature) - add DECLARE_DYNAMIC_DEBUG_CLASSBITS macro and callbacks to implement bitmap -> classid sysfs knob dyndbg: - drops exported fn: dynamic_debug_exec_queries() any potential users would just use macro, or a tweak on it. - improve info-msg to print both "old -> new" flags drm: - adapts drm debug category to dyndbg.class_id - wraps drm_*dbg() in a dyndbg Factory macro to get NOOP optimized debugs this disconnects drm.debug sysfs knob - uses DECLARE_DYNAMIC_DEBUG_CLASSBITS macro this reconnects sysfs knob
This could be -v12, but the focus and subject has wandered a bit, and patchwork CI had multiple different notions of the version.
Noteworthy changes:
- no tracefs stuff here, refocus
In contrast, the previous drm.debug approach:
- replaced drm_dbg & drm_devdbg with calls to pr_debug & dev_dbg this preserved the optional decorations: module:function:line:
- used DRM_UT_CORE => "drm:core:" prefix-string, cpp cat'd to formats this made sites selectable by matching to that format prefix
This version:
- .class_id is easier to explain, and no config/format-string diffs
- wraps drm_dbg & drm_devdbg callsites for jumplabel enablement efficiency was original goal.
- loses the optional decorations. drm has its own logmsg standards, doesn't need decorations slapped on later: could recast flags for drm specific decorations
This is based on 5.17-rc4, for no particular reason.
Its also here: in (dd-drm branch) ghlinux-ro https://github.com/jimc/linux.git (fetch)
Jim Cromie (13): dyndbg: fix static_branch manipulation @stable dyndbg: add class_id field and query support dyndbg: add DEFINE_DYNAMIC_DEBUG_CLASSBITS macro and callbacks dyndbg: drop EXPORTed dynamic_debug_exec_queries dyndbg: improve change-info to have old and new dyndbg: abstract dyndbg_site_is_printing drm_print: condense enum drm_debug_category drm_print: interpose drm_*dbg with forwarding macros drm_print: wrap drm_*_dbg in dyndbg jumplabel drm_print: refine drm_debug_enabled for dyndbg+jump-label drm_print: prefer bare printk KERN_DEBUG on generic fn drm_print: add _ddebug desc to drm_*dbg prototypes drm_print: use DEFINE_DYNAMIC_DEBUG_CLASSBITS for drm.debug
.../admin-guide/dynamic-debug-howto.rst | 7 + drivers/gpu/drm/Kconfig | 12 ++ drivers/gpu/drm/Makefile | 2 + drivers/gpu/drm/drm_print.c | 56 ++++--- include/drm/drm_print.h | 80 +++++++--- include/linux/dynamic_debug.h | 113 +++++++++++--- lib/dynamic_debug.c | 140 ++++++++++++++---- 7 files changed, 323 insertions(+), 87 deletions(-)
In https://lore.kernel.org/lkml/20211209150910.GA23668@axis.com/
Vincent's patch commented on, and worked around, a bug toggling static_branch's, when a 2nd PRINTK-ish flag was added. The bug results in a premature static_branch_disable when the 1st of 2 flags was disabled.
The cited commit computed newflags, but then in the JUMP_LABEL block, did not use that result, but used just one of the terms in it. Using newflags instead made the code work properly.
This is Vincents test-case, reduced. It needs the 2nd flag to work properly, but it's explanatory here.
pt_test() { echo 5 > /sys/module/dynamic_debug/verbose
site="module tcp" # just one callsite echo " $site =_ " > /proc/dynamic_debug/control # clear it
# A B ~A ~B for flg in +T +p "-T #broke here" -p; do echo " $site $flg " > /proc/dynamic_debug/control done;
# A B ~B ~A for flg in +T +p "-p #broke here" -T; do echo " $site $flg " > /proc/dynamic_debug/control done } pt_test
Fixes: 84da83a6ffc0 dyndbg: combine flags & mask into a struct, simplify with it CC: vincent.whitchurch@axis.com CC: stable@vger.kernel.org Signed-off-by: Jim Cromie jim.cromie@gmail.com --- lib/dynamic_debug.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c index dd7f56af9aed..a56c1286ffa4 100644 --- a/lib/dynamic_debug.c +++ b/lib/dynamic_debug.c @@ -211,10 +211,11 @@ static int ddebug_change(const struct ddebug_query *query, continue; #ifdef CONFIG_JUMP_LABEL if (dp->flags & _DPRINTK_FLAGS_PRINT) { - if (!(modifiers->flags & _DPRINTK_FLAGS_PRINT)) + if (!(newflags & _DPRINTK_FLAGS_PRINT)) static_branch_disable(&dp->key.dd_key_true); - } else if (modifiers->flags & _DPRINTK_FLAGS_PRINT) + } else if (newflags & _DPRINTK_FLAGS_PRINT) { static_branch_enable(&dp->key.dd_key_true); + } #endif dp->flags = newflags; v4pr_info("changed %s:%d [%s]%s =%s\n",
DRM defines/uses 10 enum drm_debug_category's to create exclusive classes of debug messages. To support this directly in dynamic-debug, add the following:
- struct _ddebug.class_id:4 - 4 bits is enough - define _DPRINTK_SITE_UNCLASSED 15 - see below
and the query support: - struct _ddebug_query.class_id - ddebug_parse_query - looks for "class" keyword, then calls.. - parse_class - accepts uint: 0-15, sets query.class_id and marker - vpr_info_dq - displays new field - ddebug_proc_show - append column with "cls:%d" if !UNCLASSED
With the patch, this command enables current/unclassed callsites:
#> echo drm class 15 +p > /proc/dynamic_debug/control
parse_class() accepts 0 .. _DPRINTK_SITE_UNCLASSED, which allows the
control interface to explicitly manipulate unclassed callsites.
After parsing keywords, ddebug_parse_query() sets .class_id=15, iff it wasnt explicitly set. This allows future classed/categorized callsites to be untouched by legacy (class unaware) queries.
DEFINE_DYNAMIC_DEBUG_METADATA gets _CLS(cls,) suffix and arg, and initializes the new .class_id=cls field. The old name gets the default.
Then, these _CLS(cls,...) modifications are repeated up through the stack of *dynamic_func_call* macros that use the METADATA initializer, so as to actually supply the category into it.
NOTES:
_DPRINTK_SITE_UNCLASSED: this symbol is used to initialize all existing/unclassed pr-debug callsites. Normally, the default would be zero, but DRM_UT_CORE "uses" that value, in the sense that 0 is exposed as a bit position in drm.debug. Using 15 allows identity mapping from category to class, avoiding fiddly offsets.
CC: Rasmus Villemoes linux@rasmusvillemoes.dk Signed-off-by: Jim Cromie jim.cromie@gmail.com
fixup class-id preset
fix2 --- .../admin-guide/dynamic-debug-howto.rst | 7 +++ include/linux/dynamic_debug.h | 54 ++++++++++++++----- lib/dynamic_debug.c | 48 ++++++++++++++--- 3 files changed, 88 insertions(+), 21 deletions(-)
diff --git a/Documentation/admin-guide/dynamic-debug-howto.rst b/Documentation/admin-guide/dynamic-debug-howto.rst index a89cfa083155..8ef8d7dcd140 100644 --- a/Documentation/admin-guide/dynamic-debug-howto.rst +++ b/Documentation/admin-guide/dynamic-debug-howto.rst @@ -35,6 +35,7 @@ Dynamic debug has even more useful features: - line number (including ranges of line numbers) - module name - format string + - class number:0-15
* Provides a debugfs control file: ``<debugfs>/dynamic_debug/control`` which can be read to display the complete list of known debug @@ -143,6 +144,7 @@ against. Possible keywords are::: 'module' string | 'format' string | 'line' line-range + 'class' integer:[0-15]
line-range ::= lineno | '-'lineno | @@ -217,6 +219,11 @@ line line -1605 // the 1605 lines from line 1 to line 1605 line 1600- // all lines from line 1600 to the end of the file
+class + This expects a single integer in range: 0-15. + 15 is used/reserved for existing/unclassed callsites, + and is defaulted in unless specified to >control + The flags specification comprises a change operation followed by one or more flag characters. The change operation is one of the characters:: diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h index dce631e678dd..d4b48f3cc6e8 100644 --- a/include/linux/dynamic_debug.h +++ b/include/linux/dynamic_debug.h @@ -6,6 +6,8 @@ #include <linux/jump_label.h> #endif
+#include <linux/build_bug.h> + /* * An instance of this structure is created in a special * ELF section at every dynamic debug callsite. At runtime, @@ -21,6 +23,9 @@ struct _ddebug { const char *filename; const char *format; unsigned int lineno:18; +#define CLS_BITS 4 + unsigned int class_id:CLS_BITS; +#define _DPRINTK_SITE_UNCLASSED ((1 << CLS_BITS) - 1) /* * The flags field controls the behaviour at the callsite. * The bits here are changed dynamically when the user @@ -87,7 +92,7 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor, const struct ib_device *ibdev, const char *fmt, ...);
-#define DEFINE_DYNAMIC_DEBUG_METADATA(name, fmt) \ +#define DEFINE_DYNAMIC_DEBUG_METADATA_CLS(name, cls, fmt) \ static struct _ddebug __aligned(8) \ __section("__dyndbg") name = { \ .modname = KBUILD_MODNAME, \ @@ -96,8 +101,14 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor, .format = (fmt), \ .lineno = __LINE__, \ .flags = _DPRINTK_FLAGS_DEFAULT, \ + .class_id = cls, \ _DPRINTK_KEY_INIT \ - } + }; \ + BUILD_BUG_ON_MSG(cls > _DPRINTK_SITE_UNCLASSED, \ + "classid value overflow") + +#define DEFINE_DYNAMIC_DEBUG_METADATA(name, fmt) \ + DEFINE_DYNAMIC_DEBUG_METADATA_CLS(name, _DPRINTK_SITE_UNCLASSED, fmt)
#ifdef CONFIG_JUMP_LABEL
@@ -128,18 +139,26 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
#endif /* CONFIG_JUMP_LABEL */
-#define __dynamic_func_call(id, fmt, func, ...) do { \ - DEFINE_DYNAMIC_DEBUG_METADATA(id, fmt); \ - if (DYNAMIC_DEBUG_BRANCH(id)) \ - func(&id, ##__VA_ARGS__); \ +#define __dynamic_func_call_cls(id, cls, fmt, func, ...) do { \ + DEFINE_DYNAMIC_DEBUG_METADATA_CLS(id, cls, fmt); \ + if (DYNAMIC_DEBUG_BRANCH(id)) \ + func(&id, ##__VA_ARGS__); \ } while (0)
-#define __dynamic_func_call_no_desc(id, fmt, func, ...) do { \ - DEFINE_DYNAMIC_DEBUG_METADATA(id, fmt); \ - if (DYNAMIC_DEBUG_BRANCH(id)) \ - func(__VA_ARGS__); \ +#define __dynamic_func_call_no_desc_cls(id, cls, fmt, func, ...) do { \ + DEFINE_DYNAMIC_DEBUG_METADATA_CLS(id, cls, fmt); \ + if (DYNAMIC_DEBUG_BRANCH(id)) \ + func(__VA_ARGS__); \ } while (0)
+#define __dynamic_func_call(id, fmt, func, ...) \ + __dynamic_func_call_cls(id, _DPRINTK_SITE_UNCLASSED, \ + fmt, func, ##__VA_ARGS__) + +#define __dynamic_func_call_no_desc(id, fmt, func, ...) \ + __dynamic_func_call_no_desc_cls(id, _DPRINTK_SITE_UNCLASSED, \ + fmt, func, ##__VA_ARGS__) + /* * "Factory macro" for generating a call to func, guarded by a * DYNAMIC_DEBUG_BRANCH. The dynamic debug descriptor will be @@ -148,15 +167,24 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor, * the varargs. Note that fmt is repeated in invocations of this * macro. */ +#define _dynamic_func_call_cls(cls, fmt, func, ...) \ + __dynamic_func_call_cls(__UNIQUE_ID(ddebug), cls, fmt, func, ##__VA_ARGS__) #define _dynamic_func_call(fmt, func, ...) \ - __dynamic_func_call(__UNIQUE_ID(ddebug), fmt, func, ##__VA_ARGS__) + _dynamic_func_call_cls(_DPRINTK_SITE_UNCLASSED, fmt, func, ##__VA_ARGS__) + /* * A variant that does the same, except that the descriptor is not * passed as the first argument to the function; it is only called * with precisely the macro's varargs. */ -#define _dynamic_func_call_no_desc(fmt, func, ...) \ - __dynamic_func_call_no_desc(__UNIQUE_ID(ddebug), fmt, func, ##__VA_ARGS__) +#define _dynamic_func_call_no_desc_cls(fmt, cat, func, ...) \ + __dynamic_func_call_no_desc_cls(__UNIQUE_ID(ddebug), cat, \ + fmt, func, ##__VA_ARGS__) + +#define _dynamic_func_call_no_desc(fmt, func, ...) \ + __dynamic_func_call_no_desc_cls(__UNIQUE_ID(ddebug), \ + _DPRINTK_SITE_UNCLASSED, \ + fmt, func, ##__VA_ARGS__)
#define dynamic_pr_debug(fmt, ...) \ _dynamic_func_call(fmt, __dynamic_pr_debug, \ diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c index a56c1286ffa4..ee2129becacc 100644 --- a/lib/dynamic_debug.c +++ b/lib/dynamic_debug.c @@ -55,6 +55,8 @@ struct ddebug_query { const char *function; const char *format; unsigned int first_lineno, last_lineno; + unsigned int class_id; + unsigned int class_marked:1; };
struct ddebug_iter { @@ -134,13 +136,13 @@ static void vpr_info_dq(const struct ddebug_query *query, const char *msg) fmtlen--; }
- v3pr_info("%s: func="%s" file="%s" module="%s" format="%.*s" lineno=%u-%u\n", - msg, - query->function ?: "", - query->filename ?: "", - query->module ?: "", - fmtlen, query->format ?: "", - query->first_lineno, query->last_lineno); + v3pr_info("%s: func="%s" file="%s" module="%s" format="%.*s" lineno=%u-%u class=%u\n", + msg, + query->function ?: "", + query->filename ?: "", + query->module ?: "", + fmtlen, query->format ?: "", + query->first_lineno, query->last_lineno, query->class_id); }
/* @@ -170,6 +172,10 @@ static int ddebug_change(const struct ddebug_query *query, for (i = 0; i < dt->num_ddebugs; i++) { struct _ddebug *dp = &dt->ddebugs[i];
+ /* match against the class_id, either given or default */ + if (query->class_id != dp->class_id) + continue; + /* match against the source filename */ if (query->filename && !match_wildcard(query->filename, dp->filename) && @@ -308,6 +314,21 @@ static inline int parse_lineno(const char *str, unsigned int *val) return 0; }
+static inline int parse_class(struct ddebug_query *query, const char *str) +{ + int rc; + unsigned int val; + + rc = kstrtouint(str, 10, &val); + if (rc < 0 || val > _DPRINTK_SITE_UNCLASSED) { + pr_err("expecting class:[0-%d], not %s\n", _DPRINTK_SITE_UNCLASSED, str); + return -EINVAL; + } + query->class_id = val; + query->class_marked = 1; + return 0; +} + static int parse_linerange(struct ddebug_query *query, const char *first) { char *last = strchr(first, '-'); @@ -421,6 +442,9 @@ static int ddebug_parse_query(char *words[], int nwords, } else if (!strcmp(keyword, "line")) { if (parse_linerange(query, arg)) return -EINVAL; + } else if (!strcmp(keyword, "class")) { + if (parse_class(query, arg)) + return -EINVAL; } else { pr_err("unknown keyword "%s"\n", keyword); return -EINVAL; @@ -428,6 +452,10 @@ static int ddebug_parse_query(char *words[], int nwords, if (rc) return rc; } + /* post-validate the query, set default */ + if (!query->class_marked) + query->class_id = _DPRINTK_SITE_UNCLASSED; + vpr_info_dq(query, "parsed"); return 0; } @@ -900,7 +928,11 @@ static int ddebug_proc_show(struct seq_file *m, void *p) iter->table->mod_name, dp->function, ddebug_describe_flags(dp->flags, &flags)); seq_escape(m, dp->format, "\t\r\n""); - seq_puts(m, ""\n"); + seq_puts(m, """); + + if (dp->class_id != _DPRINTK_SITE_UNCLASSED) + seq_printf(m, " cls:%u", dp->class_id); + seq_puts(m, "\n");
return 0; }
DEFINE_DYNAMIC_DEBUG_CLASSBITS(fsname, var, bitmap_desc, classes..) allows users to create a drm.debug style (bitmap) sysfs interface, to control sets of pr_debug's according to their .class_id's
This wraps existing "class" keyword and behavior:
echo "module drm -p ; module drm class 0 +p ; module drm class 2 +p" >control
With the macro in use, this is equivalent:
echo 0x05 > /sys/module/drm/parameters/debug
To use:
DEFINE_DYNAMIC_DEBUG_CLASSBITS(debug, __drm_debug, "pmfl", "drm.debug - bits => categories:", /* vector of uint:4 symbols, ala enum drm_debug_category, 15 is EOL */ DRM_UT_CORE, DRM_UT_DRIVER, DRM_UT_KMS ... );
The 3rd arg is a string with any of the dyndbg.flags [pmflt_]+ Full exposure of the flags here lets the module author:
- fully customize/take-over the decorations of enabled sites. generally leaving decorations to user is preferred.
- aim the debug-stream: now printk, later tracefs. using both together means more work (p or T, in practice) iface doesn't care about new flags added later
- declare 2 separate sysfs-knobs, one each for p, T, if desired.
- decorations are per callsite, shared across sysfs-knobs for any controlled classes
To support the macro, the patch adds:
- int param_set_dyndbg_classbits() - int param_get_dyndbg_classbits() - struct kernel_param_ops param_ops_dyndbg_classbits
Following the model of kernel/params.c STANDARD_PARAM_DEFS, these are non-static and exported.
get/set use an augmented kernel_param; the arg refs a new struct dyndbg_bitmap_param containing:
A- the vector of classes (drm.debug "categories") being controlled
This in-line vector of constants (uint [0-14]) specifies a sequence of controlling bits (by position, starting at 0) with the values naming the class_id's mapped to that bit.
A value of _DPRINTK_SITE_UNCLASSED terminates the vector processing by param_set_dyndbg_classbits(), and is appended by the macro to insure a defined termination after max 15 classes are applied.
Technically, the vector is a flex-array, but its size is practically limited to max 15 in length (repeats are pointless).
B- a pointer to the user module's ulong holding the bits/state.
By accessing client's bit-state, we coordinate with existing code that still uses drm_debug_enabled(), so they work unchanged. The change to ulong allows use of BIT() etc.
NOTES:
_DPRINTK_SITE_UNCLASSED = 15, ie 2**CLS_BITS-1, deserves special mention; it already marks all existing pr-debug callsites, only the new drm.debug callsites are initialized to other (DRM_UT_*) values.
_DPRINTK_SITE_UNCLASSED is used in param_set_dyndbg_classbits() to limit the range of bits that are processed to what fits in uint:4. It also terminates the class-id list passed into the macro, so dont use it halfway through your list of classes-to-control.
param_set_dyndbg_classbits() compares new vs old bits, and only updates each class on changes. This maximally preserves the underlying state, which may have been customized at some point via `echo $cmd >control`. So if users really want to know that all prdbgs are set precisely, they must pre-clear then set.
Identity mapping in (A) is encouraged. Your vector should exclude 15, if used, it terminates the list prematurely; any following bit mappings will be ignored (it is the default/non category).
The whole (A) vector/list passed to the macro is:
- not strictly needed: 0-N bits are scanned, only N is needed in the macro interface to do this, not the whole list.
- 0-N list allows juggling the bit->class map Identity map is preferred. 15 terminates list if used. (macro impl does this)
That said, (A) is self-documenting; the explicit list is greppable, 'DRM_UT_*' provides lots of clues. Further, it could be upgraded, something like:
_pick_sym_(DRM_UT_CORE, "mumble something useful about CORE debug")
_pick_sym_(a,b) a // gives us what we need here _pick_help_(a,b) #a " : " b // mod-info fodder
Signed-off-by: Jim Cromie jim.cromie@gmail.com --- include/linux/dynamic_debug.h | 50 +++++++++++++++++++++++ lib/dynamic_debug.c | 77 +++++++++++++++++++++++++++++++++++ 2 files changed, 127 insertions(+)
diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h index d4b48f3cc6e8..e83c4e36ad29 100644 --- a/include/linux/dynamic_debug.h +++ b/include/linux/dynamic_debug.h @@ -209,6 +209,10 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor, KERN_DEBUG, prefix_str, prefix_type, \ rowsize, groupsize, buf, len, ascii)
+struct kernel_param; +int param_set_dyndbg_classbits(const char *instr, const struct kernel_param *kp); +int param_get_dyndbg_classbits(char *buffer, const struct kernel_param *kp); + #else /* !CONFIG_DYNAMIC_DEBUG_CORE */
#include <linux/string.h> @@ -255,6 +259,52 @@ static inline int dynamic_debug_exec_queries(const char *query, const char *modn return 0; }
+struct kernel_param; +static inline int param_set_dyndbg_classbits(const char *instr, const struct kernel_param *kp) +{ return 0; } +static inline int param_get_dyndbg_classbits(char *buffer, const struct kernel_param *kp) +{ return 0; } + #endif /* !CONFIG_DYNAMIC_DEBUG_CORE */
+#define FLAGS_LEN 8 +struct dyndbg_classbits_param { + unsigned long *bits; /* ref to shared state */ + const char flags[FLAGS_LEN]; /* toggle these flags on bit-changes */ + const int classes[]; /* indexed by bitpos */ +}; + +#if defined(CONFIG_DYNAMIC_DEBUG) || defined(CONFIG_DYNAMIC_DEBUG_CORE) +/** + * DEFINE_DYNAMIC_DEBUG_CLASSBITS() - bitmap control of classed pr_debugs + * @sysname: sysfs-node name + * @_var: C-identifier holding bit-vector (Bits 0-14 are usable) + * @_flgs: string with dyndbg flags: 'p' and/or 'T', and maybe "fmlt" also. + * @desc: string summarizing the controls provided + * @classes: vector of callsite.class_id's (uint:4, 15 is reserved) + * + * This macro implements a DRM.debug API style bitmap, mapping bits + * 0-14 to classes of prdbg's, as initialized in their .class_id fields. + * @_flgs chooses the debug recipient; p - syslog, T - tracefs, and + * can include log decorations; m - module, f - function, l - line_num + */ +#define DEFINE_DYNAMIC_DEBUG_CLASSBITS(fsname, _var, _flgs, desc, ...) \ + MODULE_PARM_DESC(fsname, desc); \ + static struct dyndbg_classbits_param ddcats_##_var = { \ + .bits = &(_var), \ + .flags = _flgs, \ + .classes = { __VA_ARGS__, _DPRINTK_SITE_UNCLASSED } \ + }; \ + module_param_cb(fsname, ¶m_ops_dyndbg_classbits, \ + &ddcats_##_var, 0644) + +extern const struct kernel_param_ops param_ops_dyndbg_classbits; + +#else /* no dyndbg configured, throw error on macro use */ + +#define DEFINE_DYNAMIC_DEBUG_CLASSBITS(fsname, var, bitmap_desc, ...) \ + BUILD_BUG_ON_MSG(1, "CONFIG_DYNAMIC_DEBUG* needed to use this macro: " #fsname) + +#endif + #endif diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c index ee2129becacc..7eb1c31f870d 100644 --- a/lib/dynamic_debug.c +++ b/lib/dynamic_debug.c @@ -611,6 +611,83 @@ int dynamic_debug_exec_queries(const char *query, const char *modname) } EXPORT_SYMBOL_GPL(dynamic_debug_exec_queries);
+#ifdef CONFIG_MODULES +#define KP_MOD_NAME kp->mod->name +#else +#define KP_MOD_NAME NULL /* wildcard */ +#endif +#define FMT_QUERY_SIZE 128 /* typically need <40 */ +/** + * param_set_dyndbg_classbits - bits => categories >control setter + * @instr: string echo>d to sysfs + * @kp: kp->arg has state: bits, map + * + * Enable/disable prdbgs by their "category", as specified in the + * DEFINE_DYNAMIC_DEBUG_BITGRPS.classbits argument. + * + * Returns: 0 or <0 if error. + */ +int param_set_dyndbg_classbits(const char *instr, const struct kernel_param *kp) +{ + unsigned long inbits; + int rc, i, matches = 0, totct = 0; + char query[FMT_QUERY_SIZE]; + const struct dyndbg_classbits_param *dcp = kp->arg; + + if (!dcp) { + pr_err("set_dyndbg_classbits: no bits=>queries map\n"); + return -EINVAL; + } + rc = kstrtoul(instr, 0, &inbits); + if (rc) { + pr_err("set_dyndbg_classbits: expecting unsigned int\n"); + return rc; + } + vpr_info("set_dyndbg_classbits: new 0x%lx old 0x%lx\n", inbits, *dcp->bits); + + for (i = 0; i < _DPRINTK_SITE_UNCLASSED && + dcp->classes[i] < _DPRINTK_SITE_UNCLASSED; i++) { + + if (test_bit(i, &inbits) == test_bit(i, dcp->bits)) + continue; + snprintf(query, FMT_QUERY_SIZE, "class %d %cT", dcp->classes[i], + test_bit(i, &inbits) ? '+' : '-'); + + matches = ddebug_exec_queries(query, KP_MOD_NAME); + + v2pr_info("bit-%d: %d matches on class:%u\n", i, + matches, dcp->classes[i]); + totct += matches; + } + *dcp->bits = inbits; + vpr_info("total matches: %d\n", totct); + return 0; +} +EXPORT_SYMBOL(param_set_dyndbg_classbits); + +/** + * param_get_dyndbg_classbits - classbits reader + * @buffer: string description of controlled bits -> classes + * @kp: kp->arg has state: bits, map + * + * Reads last written bits, underlying prdbg state may have changed since. + * Returns: #chars written or <0 on error + */ +int param_get_dyndbg_classbits(char *buffer, const struct kernel_param *kp) +{ + const struct dyndbg_classbits_param *p = kp->arg; + unsigned long val = *p->bits; + + return scnprintf(buffer, PAGE_SIZE, "0x%lx\n", val); +} +EXPORT_SYMBOL(param_get_dyndbg_classbits); + +const struct kernel_param_ops param_ops_dyndbg_classbits = { + .set = param_set_dyndbg_classbits, + .get = param_get_dyndbg_classbits, +}; +EXPORT_SYMBOL(param_ops_dyndbg_classbits); + #define PREFIX_SIZE 64
static int remaining(int wrote)
This exported fn is effectively obsoleted by Commit:HEAD~2, so remove it.
The export was added here: commit a2d375eda771 ("dyndbg: refine export, rename to dynamic_debug_exec_queries()") commit 4c0d77828d4f ("dyndbg: export ddebug_exec_queries")
Its intent was to allow drm.debug to use the exported function to implement its drm.debug bitmap api using dynamic_debug.
Instead, HEAD~2 implements the bitmap inside dyndbg, and exposes it in a macro declarator, and HEAD~1 uses the macro to connect __drm_debug to the supporting callbacks.
Since there are no other expected users, and any prospects would likely reuse the bitmap or a straightforward extension of it, we can drop this function until its really needed.
This also drops the CONFIG_DYNAMIC_DEBUG=N stub-func, and its pr_warn(), which I avoided in 2012, then added in 2020 :-/
Signed-off-by: Jim Cromie jim.cromie@gmail.com --- include/linux/dynamic_debug.h | 9 --------- lib/dynamic_debug.c | 29 ----------------------------- 2 files changed, 38 deletions(-)
diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h index e83c4e36ad29..664bb83778d2 100644 --- a/include/linux/dynamic_debug.h +++ b/include/linux/dynamic_debug.h @@ -60,9 +60,6 @@ struct _ddebug {
#if defined(CONFIG_DYNAMIC_DEBUG_CORE)
-/* exported for module authors to exercise >control */ -int dynamic_debug_exec_queries(const char *query, const char *modname); - int ddebug_add_module(struct _ddebug *tab, unsigned int n, const char *modname); extern int ddebug_remove_module(const char *mod_name); @@ -253,12 +250,6 @@ static inline int ddebug_dyndbg_module_param_cb(char *param, char *val, rowsize, groupsize, buf, len, ascii); \ } while (0)
-static inline int dynamic_debug_exec_queries(const char *query, const char *modname) -{ - pr_warn("kernel not built with CONFIG_DYNAMIC_DEBUG_CORE\n"); - return 0; -} - struct kernel_param; static inline int param_set_dyndbg_classbits(const char *instr, const struct kernel_param *kp) { return 0; } diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c index 7eb1c31f870d..60b2572e64f0 100644 --- a/lib/dynamic_debug.c +++ b/lib/dynamic_debug.c @@ -582,35 +582,6 @@ static int ddebug_exec_queries(char *query, const char *modname) return nfound; }
-/** - * dynamic_debug_exec_queries - select and change dynamic-debug prints - * @query: query-string described in admin-guide/dynamic-debug-howto - * @modname: string containing module name, usually &module.mod_name - * - * This uses the >/proc/dynamic_debug/control reader, allowing module - * authors to modify their dynamic-debug callsites. The modname is - * canonically struct module.mod_name, but can also be null or a - * module-wildcard, for example: "drm*". - */ -int dynamic_debug_exec_queries(const char *query, const char *modname) -{ - int rc; - char *qry; /* writable copy of query */ - - if (!query) { - pr_err("non-null query/command string expected\n"); - return -EINVAL; - } - qry = kstrndup(query, PAGE_SIZE, GFP_KERNEL); - if (!qry) - return -ENOMEM; - - rc = ddebug_exec_queries(qry, modname); - kfree(qry); - return rc; -} -EXPORT_SYMBOL_GPL(dynamic_debug_exec_queries); - #ifdef CONFIG_MODULES #define KP_MOD_NAME kp->mod->name #else
move site.flag update after the v4pr_info("change") message, and improve the message to print both old and new flag values.
Heres new form: dyndbg: changed net/ipv4/tcp.c:2424 [tcp]tcp_recvmsg_locked pT -> _
Signed-off-by: Jim Cromie jim.cromie@gmail.com --- lib/dynamic_debug.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c index 60b2572e64f0..ab93b370d489 100644 --- a/lib/dynamic_debug.c +++ b/lib/dynamic_debug.c @@ -158,7 +158,7 @@ static int ddebug_change(const struct ddebug_query *query, struct ddebug_table *dt; unsigned int newflags; unsigned int nfound = 0; - struct flagsbuf fbuf; + struct flagsbuf fbuf, nbuf;
/* search for matching ddebugs */ mutex_lock(&ddebug_lock); @@ -223,11 +223,12 @@ static int ddebug_change(const struct ddebug_query *query, static_branch_enable(&dp->key.dd_key_true); } #endif + v4pr_info("changed %s:%d [%s]%s %s -> %s\n", + trim_prefix(dp->filename), dp->lineno, + dt->mod_name, dp->function, + ddebug_describe_flags(dp->flags, &fbuf), + ddebug_describe_flags(newflags, &nbuf)); dp->flags = newflags; - v4pr_info("changed %s:%d [%s]%s =%s\n", - trim_prefix(dp->filename), dp->lineno, - dt->mod_name, dp->function, - ddebug_describe_flags(dp->flags, &fbuf)); } } mutex_unlock(&ddebug_lock);
Hide flags test in a macro. no functional changes.
Signed-off-by: Jim Cromie jim.cromie@gmail.com --- include/linux/dynamic_debug.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h index 664bb83778d2..106065244f73 100644 --- a/include/linux/dynamic_debug.h +++ b/include/linux/dynamic_debug.h @@ -56,7 +56,7 @@ struct _ddebug { #endif } __attribute__((aligned(8)));
- +#define dyndbg_site_is_printing(desc) (desc->flags & _DPRINTK_FLAGS_PRINT)
#if defined(CONFIG_DYNAMIC_DEBUG_CORE)
enum drm_debug_category has 10 "classes", explicitly initialized with 0x-bitmasks which could be simplified as BIT(X)s. But lets go further: use natural enumeration (int, starting at 0), and do the BIT(cat) in drm_debug_enabled(cat) at runtime.
While this slightly pessimizes the bit-test, the category now fits in 4 bits, allowing it in struct _ddebug.class_id:4. This sets us up to adapt drm to use dyndbg with JUMP_LABEL, thus avoiding all those bit-tests anyway.
Signed-off-by: Jim Cromie jim.cromie@gmail.com --- include/drm/drm_print.h | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-)
diff --git a/include/drm/drm_print.h b/include/drm/drm_print.h index 22fabdeed297..b3b470440e46 100644 --- a/include/drm/drm_print.h +++ b/include/drm/drm_print.h @@ -279,49 +279,49 @@ enum drm_debug_category { * @DRM_UT_CORE: Used in the generic drm code: drm_ioctl.c, drm_mm.c, * drm_memory.c, ... */ - DRM_UT_CORE = 0x01, + DRM_UT_CORE, /** * @DRM_UT_DRIVER: Used in the vendor specific part of the driver: i915, * radeon, ... macro. */ - DRM_UT_DRIVER = 0x02, + DRM_UT_DRIVER, /** * @DRM_UT_KMS: Used in the modesetting code. */ - DRM_UT_KMS = 0x04, + DRM_UT_KMS, /** * @DRM_UT_PRIME: Used in the prime code. */ - DRM_UT_PRIME = 0x08, + DRM_UT_PRIME, /** * @DRM_UT_ATOMIC: Used in the atomic code. */ - DRM_UT_ATOMIC = 0x10, + DRM_UT_ATOMIC, /** * @DRM_UT_VBL: Used for verbose debug message in the vblank code. */ - DRM_UT_VBL = 0x20, + DRM_UT_VBL, /** * @DRM_UT_STATE: Used for verbose atomic state debugging. */ - DRM_UT_STATE = 0x40, + DRM_UT_STATE, /** * @DRM_UT_LEASE: Used in the lease code. */ - DRM_UT_LEASE = 0x80, + DRM_UT_LEASE, /** * @DRM_UT_DP: Used in the DP code. */ - DRM_UT_DP = 0x100, + DRM_UT_DP, /** * @DRM_UT_DRMRES: Used in the drm managed resources code. */ - DRM_UT_DRMRES = 0x200, + DRM_UT_DRMRES };
static inline bool drm_debug_enabled(enum drm_debug_category category) { - return unlikely(__drm_debug & category); + return unlikely(__drm_debug & BIT(category)); }
/*
drm_dev_dbg() & drm_dbg() sit below the categorized layer of the DRM debug API, and implement most of it. These are good places to insert dynamic-debug jump-label mechanics, allowing DRM to avoid the runtime cost of drm_debug_enabled().
Set up for this by changing the func names by adding '__' prefixes, and define forwarding macros to the new names.
no functional changes.
memory cost baseline: (unchanged) bash-5.1# drms_load [ 9.220389] dyndbg: 1 debug prints in module drm [ 9.224426] ACPI: bus type drm_connector registered [ 9.302192] dyndbg: 2 debug prints in module ttm [ 9.305033] dyndbg: 8 debug prints in module video [ 9.627563] dyndbg: 127 debug prints in module i915 [ 9.721505] AMD-Vi: AMD IOMMUv2 functionality not available on this system - This is not a bug. [ 10.091345] dyndbg: 2196 debug prints in module amdgpu [ 10.106589] [drm] amdgpu kernel modesetting enabled. [ 10.107270] amdgpu: CRAT table not found [ 10.107926] amdgpu: Virtual CRAT table created for CPU [ 10.108398] amdgpu: Topology: Add CPU node [ 10.168507] dyndbg: 3 debug prints in module wmi [ 10.329587] dyndbg: 3 debug prints in module nouveau
Signed-off-by: Jim Cromie jim.cromie@gmail.com --- drivers/gpu/drm/drm_print.c | 10 +++++----- include/drm/drm_print.h | 9 +++++++-- 2 files changed, 12 insertions(+), 7 deletions(-)
diff --git a/drivers/gpu/drm/drm_print.c b/drivers/gpu/drm/drm_print.c index f783d4963d4b..e45ba224e57c 100644 --- a/drivers/gpu/drm/drm_print.c +++ b/drivers/gpu/drm/drm_print.c @@ -256,8 +256,8 @@ void drm_dev_printk(const struct device *dev, const char *level, } EXPORT_SYMBOL(drm_dev_printk);
-void drm_dev_dbg(const struct device *dev, enum drm_debug_category category, - const char *format, ...) +void __drm_dev_dbg(const struct device *dev, enum drm_debug_category category, + const char *format, ...) { struct va_format vaf; va_list args; @@ -278,9 +278,9 @@ void drm_dev_dbg(const struct device *dev, enum drm_debug_category category,
va_end(args); } -EXPORT_SYMBOL(drm_dev_dbg); +EXPORT_SYMBOL(__drm_dev_dbg);
-void __drm_dbg(enum drm_debug_category category, const char *format, ...) +void ___drm_dbg(enum drm_debug_category category, const char *format, ...) { struct va_format vaf; va_list args; @@ -297,7 +297,7 @@ void __drm_dbg(enum drm_debug_category category, const char *format, ...)
va_end(args); } -EXPORT_SYMBOL(__drm_dbg); +EXPORT_SYMBOL(___drm_dbg);
void __drm_err(const char *format, ...) { diff --git a/include/drm/drm_print.h b/include/drm/drm_print.h index b3b470440e46..4bed99326631 100644 --- a/include/drm/drm_print.h +++ b/include/drm/drm_print.h @@ -334,7 +334,7 @@ __printf(3, 4) void drm_dev_printk(const struct device *dev, const char *level, const char *format, ...); __printf(3, 4) -void drm_dev_dbg(const struct device *dev, enum drm_debug_category category, +void __drm_dev_dbg(const struct device *dev, enum drm_debug_category category, const char *format, ...);
/** @@ -383,6 +383,9 @@ void drm_dev_dbg(const struct device *dev, enum drm_debug_category category, } \ })
+#define drm_dev_dbg(dev, cat, fmt, ...) \ + __drm_dev_dbg(dev, cat, fmt, ##__VA_ARGS__) + /** * DRM_DEV_DEBUG() - Debug output for generic drm code * @@ -484,10 +487,12 @@ void drm_dev_dbg(const struct device *dev, enum drm_debug_category category, */
__printf(2, 3) -void __drm_dbg(enum drm_debug_category category, const char *format, ...); +void ___drm_dbg(enum drm_debug_category category, const char *format, ...); __printf(1, 2) void __drm_err(const char *format, ...);
+#define __drm_dbg(fmt, ...) ___drm_dbg(fmt, ##__VA_ARGS__) + /* Macros to make printk easier */
#define _DRM_PRINTK(once, level, fmt, ...) \
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 makes the (~4000) callsites controllable, typically by class:
# 0 is DRM_UT_CORE #> echo module drm class 0 +p > /proc/dynamic_debug/control
=N: keeps direct forwarding: drm_*_dbg -> __drm_*_dbg()
I added the CONFIG_DRM_USE_DYNAMIC_DEBUG item because of the .data footprint cost of per-callsite control; 56 bytes/site * ~2k,4k callsites (for i915, amdgpu), which is significant enough that a user might not want it. Using CONFIG_DYNAMIC_DEBUG_CORE only eliminates the builtin portion, leaving only drm modules, but still 200k of module data is a lot.
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 b1f22e457fd0..ec14a1cd4449 100644 --- a/drivers/gpu/drm/Kconfig +++ b/drivers/gpu/drm/Kconfig @@ -63,6 +63,18 @@ 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_DEBUG_SELFTEST tristate "kselftests for DRM" depends on DRM diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile index 301a44dc18e3..24e6410d6c0e 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 4bed99326631..06f0ee06be1f 100644 --- a/include/drm/drm_print.h +++ b/include/drm/drm_print.h @@ -383,8 +383,14 @@ 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 @@ -491,7 +497,13 @@ 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 */
In order to use dynamic-debug's jump-label optimization in drm-debug, its clarifying to refine drm_debug_enabled into 3 uses:
1. drm_debug_enabled - legacy, public 2. __drm_debug_enabled - optimized for dyndbg jump-label enablement. 3. _drm_debug_enabled - pr_debug instrumented, observable
1. The legacy version always checks the bits.
2. is privileged, for use by __drm_dbg(), __drm_dev_dbg(), which do an early return unless the category is enabled (free of call/NOOP side effects). For dyndbg builds, debug callsites are selectively "pre-enabled", so __drm_debug_enabled() short-circuits to true there. Remaining callers of 1 may be able to use 2, case by case.
3. is 1st wrapped in a macro, with a pr_debug, which reports each usage in /proc/dynamic_debug/control, making it observable in the logs. The macro lets the pr_debug see the real caller, not an inline function.
When plugged into 1, it identified ~10 remaining callers of the function, leading to the follow-on cleanup patch, and would allow activating the pr_debugs, estimating the callrate, and the potential savings by using the wrapper macro. It is unused ATM, but it fills out the picture.
Signed-off-by: Jim Cromie jim.cromie@gmail.com --- drivers/gpu/drm/drm_print.c | 4 ++-- include/drm/drm_print.h | 28 ++++++++++++++++++++++++++++ 2 files changed, 30 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/drm_print.c b/drivers/gpu/drm/drm_print.c index e45ba224e57c..92e6e18026da 100644 --- a/drivers/gpu/drm/drm_print.c +++ b/drivers/gpu/drm/drm_print.c @@ -262,7 +262,7 @@ void __drm_dev_dbg(const struct device *dev, enum drm_debug_category category, struct va_format vaf; va_list args;
- if (!drm_debug_enabled(category)) + if (!__drm_debug_enabled(category)) return;
va_start(args, format); @@ -285,7 +285,7 @@ void ___drm_dbg(enum drm_debug_category category, const char *format, ...) struct va_format vaf; va_list args;
- if (!drm_debug_enabled(category)) + if (!__drm_debug_enabled(category)) return;
va_start(args, format); diff --git a/include/drm/drm_print.h b/include/drm/drm_print.h index 06f0ee06be1f..38ef044d786e 100644 --- a/include/drm/drm_print.h +++ b/include/drm/drm_print.h @@ -319,11 +319,39 @@ 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 *
drm_print.c calls pr_debug() just once, from __drm_printfn_debug(), which is a generic/service fn. The callsite is compile-time enabled by DEBUG in both DYNAMIC_DEBUG=y/n builds.
For dyndbg builds, reverting this callsite back to bare printk is correcting a few anti-features:
1- callsite is generic, serves multiple drm users. its hardwired on currently could accidentally: #> echo -p > /proc/dynamic_debug/control
2- optional "decorations" by dyndbg are unhelpful/misleading they describe only the generic site, not end users
IOW, 1,2 are unhelpful at best, and possibly confusing.
reverting yields a nominal data and text shrink:
text data bss dec hex filename 462583 36604 54592 553779 87333 /lib/modules/5.16.0-rc4-lm1-00008-ged3eac8ceeea/kernel/drivers/gpu/drm/drm.ko 462515 36532 54592 553639 872a7 /lib/modules/5.16.0-rc4-lm1-00009-g6ce0b88d2539-dirty/kernel/drivers/gpu/drm/drm.ko
NB: this was noticed using _drm_debug_enabled(), added earlier.
Signed-off-by: Jim Cromie jim.cromie@gmail.com --- drivers/gpu/drm/drm_print.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/drm_print.c b/drivers/gpu/drm/drm_print.c index 92e6e18026da..24c57b92dc69 100644 --- a/drivers/gpu/drm/drm_print.c +++ b/drivers/gpu/drm/drm_print.c @@ -23,8 +23,6 @@ * Rob Clark robdclark@gmail.com */
-#define DEBUG /* for pr_debug() */ - #include <linux/stdarg.h>
#include <linux/io.h> @@ -162,7 +160,8 @@ EXPORT_SYMBOL(__drm_printfn_info);
void __drm_printfn_debug(struct drm_printer *p, struct va_format *vaf) { - pr_debug("%s %pV", p->prefix, vaf); + /* pr_debug callsite decorations are unhelpful here */ + printk(KERN_DEBUG "%s %pV", p->prefix, vaf); } EXPORT_SYMBOL(__drm_printfn_debug);
Add a struct _ddebug ptr to drm_dbg() and drm_dev_dbg() protos.
And upgrade the current use of _dynamic_func_call_no_desc(); ie drop the '_no_desc', since the factory macro's callees (these 2 functions) are now expecting the arg.
This lets those functions act more like pr_debug(). It also means that these functions don't just get the decorations from an underlying implementation. DRM already has standards for logging/messaging; tossing optional decorations on top may not help.
use that info
provide it to dyndbg [1], which can then control debug enablement and decoration for all those drm.debug callsites.
For CONFIG_DRM_USE_DYNAMIC_DEBUG=N, just pass null. NB: desc->class_id is redundant with category, but !!desc dependent.
Signed-off-by: Jim Cromie jim.cromie@gmail.com --- drivers/gpu/drm/drm_print.c | 23 +++++++++++++---------- include/drm/drm_print.h | 23 ++++++++++++----------- 2 files changed, 25 insertions(+), 21 deletions(-)
diff --git a/drivers/gpu/drm/drm_print.c b/drivers/gpu/drm/drm_print.c index 24c57b92dc69..c9b2a2ab0d3d 100644 --- a/drivers/gpu/drm/drm_print.c +++ b/drivers/gpu/drm/drm_print.c @@ -255,8 +255,8 @@ void drm_dev_printk(const struct device *dev, const char *level, } EXPORT_SYMBOL(drm_dev_printk);
-void __drm_dev_dbg(const struct device *dev, enum drm_debug_category category, - const char *format, ...) +void __drm_dev_dbg(struct _ddebug *desc, const struct device *dev, + enum drm_debug_category category, const char *format, ...) { struct va_format vaf; va_list args; @@ -264,22 +264,25 @@ void __drm_dev_dbg(const struct device *dev, enum drm_debug_category category, if (!__drm_debug_enabled(category)) return;
+ /* we know we are printing for either syslog, tracefs, or both */ va_start(args, format); vaf.fmt = format; vaf.va = &args;
- if (dev) - dev_printk(KERN_DEBUG, dev, "[" DRM_NAME ":%ps] %pV", - __builtin_return_address(0), &vaf); - else - printk(KERN_DEBUG "[" DRM_NAME ":%ps] %pV", - __builtin_return_address(0), &vaf); - + if (dev) { + if (dyndbg_site_is_printing(desc)) + dev_printk(KERN_DEBUG, dev, "[" DRM_NAME ":%ps] %pV", + __builtin_return_address(0), &vaf); + } else { + if (dyndbg_site_is_printing(desc)) + printk(KERN_DEBUG "[" DRM_NAME ":%ps] %pV", + __builtin_return_address(0), &vaf); + } va_end(args); } EXPORT_SYMBOL(__drm_dev_dbg);
-void ___drm_dbg(enum drm_debug_category category, const char *format, ...) +void ___drm_dbg(struct _ddebug *desc, enum drm_debug_category category, const char *format, ...) { struct va_format vaf; va_list args; diff --git a/include/drm/drm_print.h b/include/drm/drm_print.h index 38ef044d786e..13d52b60f388 100644 --- a/include/drm/drm_print.h +++ b/include/drm/drm_print.h @@ -31,6 +31,7 @@ #include <linux/seq_file.h> #include <linux/device.h> #include <linux/debugfs.h> +#include <linux/dynamic_debug.h>
#include <drm/drm.h>
@@ -361,9 +362,9 @@ static inline bool drm_debug_enabled(enum drm_debug_category category) __printf(3, 4) void drm_dev_printk(const struct device *dev, const char *level, const char *format, ...); -__printf(3, 4) -void __drm_dev_dbg(const struct device *dev, enum drm_debug_category category, - const char *format, ...); +__printf(4, 5) +void __drm_dev_dbg(struct _ddebug *desc, const struct device *dev, + enum drm_debug_category category, const char *format, ...);
/** * DRM_DEV_ERROR() - Error output. @@ -413,11 +414,11 @@ 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__) + __drm_dev_dbg(NULL, 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__) + _dynamic_func_call_cls(cat, fmt, __drm_dev_dbg, \ + dev, cat, fmt, ##__VA_ARGS__) #endif
/** @@ -520,17 +521,17 @@ void __drm_dev_dbg(const struct device *dev, enum drm_debug_category category, * Prefer drm_device based logging over device or prink based logging. */
-__printf(2, 3) -void ___drm_dbg(enum drm_debug_category category, const char *format, ...); +__printf(3, 4) +void ___drm_dbg(struct _ddebug *desc, 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__) +#define __drm_dbg(fmt, ...) ___drm_dbg(NULL, fmt, ##__VA_ARGS__) #else #define __drm_dbg(cat, fmt, ...) \ - _dynamic_func_call_no_desc(fmt, ___drm_dbg, \ - cat, fmt, ##__VA_ARGS__) + _dynamic_func_call_cls(cat, fmt, ___drm_dbg, \ + cat, fmt, ##__VA_ARGS__) #endif
/* Macros to make printk easier */
if CONFIG_DRM_USE_DYNAMIC_DEBUG=y, use new macro to create the sysfs bitmap to control drm.debug callsites.
DEFINE_DYNAMIC_DEBUG_CLASSBITS( debug, __drm_debug, "p", "drm.debug - control summary", /* inline vector of _ddebug.class_id's to be controlled, max 14 vals */ DRM_UT_CORE, DRM_UT_DRIVER, DRM_UT_KMS, DRM_UT_PRIME, DRM_UT_ATOMIC, DRM_UT_VBL, DRM_UT_STATE, DRM_UT_LEASE, DRM_UT_DP, DRM_UT_DRMRES );
NOTES:
The @_flgs used here is "p", so this bitmap enables input to syslog only, matching legacy behavior.
Also, no "fmlt" decorator flags are used here; that is discouraged, as it then toggles those flags along with the "p". This would overwrite any customizations a user added since the sysfs-knob was last used. Still, there may be cases/reasons.
_ddebug.class_id is uint:4, values 0-14 are valid. 15 is reserved for non-classified callsites (regular pr_debugs). Using it terminates the scan, don't use it halfway through your list.
Signed-off-by: Jim Cromie jim.cromie@gmail.com --- drivers/gpu/drm/drm_print.c | 20 ++++++++++++++++++-- include/drm/drm_print.h | 4 ++-- 2 files changed, 20 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/drm_print.c b/drivers/gpu/drm/drm_print.c index c9b2a2ab0d3d..d916daa384e5 100644 --- a/drivers/gpu/drm/drm_print.c +++ b/drivers/gpu/drm/drm_print.c @@ -38,7 +38,7 @@ * __drm_debug: Enable debug output. * Bitmask of DRM_UT_x. See include/drm/drm_print.h for details. */ -unsigned int __drm_debug; +unsigned long __drm_debug; EXPORT_SYMBOL(__drm_debug);
MODULE_PARM_DESC(debug, "Enable debug output, where each bit enables a debug category.\n" @@ -50,7 +50,23 @@ MODULE_PARM_DESC(debug, "Enable debug output, where each bit enables a debug cat "\t\tBit 5 (0x20) will enable VBL messages (vblank code)\n" "\t\tBit 7 (0x80) will enable LEASE messages (leasing code)\n" "\t\tBit 8 (0x100) will enable DP messages (displayport code)"); -module_param_named(debug, __drm_debug, int, 0600); + +#if !defined(CONFIG_DRM_USE_DYNAMIC_DEBUG) +module_param_named(debug, __drm_debug, ulong, 0600); +#else +DEFINE_DYNAMIC_DEBUG_CLASSBITS(debug, __drm_debug, "p", + "enable drm.debug categories - 1 bit per category", + DRM_UT_CORE, + DRM_UT_DRIVER, + DRM_UT_KMS, + DRM_UT_PRIME, + DRM_UT_ATOMIC, + DRM_UT_VBL, + DRM_UT_STATE, + DRM_UT_LEASE, + DRM_UT_DP, + DRM_UT_DRMRES); +#endif
void __drm_puts_coredump(struct drm_printer *p, const char *str) { diff --git a/include/drm/drm_print.h b/include/drm/drm_print.h index 13d52b60f388..419140bf992d 100644 --- a/include/drm/drm_print.h +++ b/include/drm/drm_print.h @@ -36,7 +36,7 @@ #include <drm/drm.h>
/* Do *not* use outside of drm_print.[ch]! */ -extern unsigned int __drm_debug; +extern unsigned long __drm_debug;
/** * DOC: print @@ -527,7 +527,7 @@ __printf(1, 2) void __drm_err(const char *format, ...);
#if !defined(CONFIG_DRM_USE_DYNAMIC_DEBUG) -#define __drm_dbg(fmt, ...) ___drm_dbg(NULL, fmt, ##__VA_ARGS__) +#define __drm_dbg(cat, fmt, ...) ___drm_dbg(NULL, cat, fmt, ##__VA_ARGS__) #else #define __drm_dbg(cat, fmt, ...) \ _dynamic_func_call_cls(cat, fmt, ___drm_dbg, \
dri-devel@lists.freedesktop.org
-
Jim Cromie