Messages in this thread Patch in this message | | | From | Jim Cromie <> | Subject | [RFC PATCH v6 34/34] dyndbg: prototype print-once and print-ratelimited RFC | Date | Sat, 29 May 2021 14:00:29 -0600 |
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Expand ddebug.flags to 11 bits, and define new flags to support pr_debug_once() and pr_debug_ratelimited() semantics:
echo module main +o > control # init/main runs once anyway echo module foo +r > control # turn on ratelimiting echo module foo +g > control # turn on group flag
Test these conditions in new is_onced_or_ratelimited(), and call it from __dynamic_pr_debug and others.
print-once: can be done with just 2 bits in flags;
.o _DPRINTK_FLAGS_ONCE enables state test and set .P _DPRINTK_FLAGS_PRINTED state bit
Just adding the flags lets the existing code operate them. We will need new code to enforce constraints on flag combos; '+ro' is nonsense, but this can wait, or can take a new meaning.
is_onced_or_ratelimited() should be correct for +o, and should be testable now. tbd.
rate-limiting: . for now, reserve the flag only ! .r _DPRINTK_FLAGS_RATELIMITED - track & limit prdbgs callrate
Intention is to wait til a prdebug is called, and if RATELIMITED is set, THEN lookup a RateLimitState (RL) for it. If found, bump its state and return true/false, otherwise create one, initialize it and return false.
That lookup is basically a hash, with 2 part key: . &builtin-vector-base OR &module or the hash(s) could hang off the header struct . ._back OR ._map chosen by _DPRINTK_FLAGS_GROUPED choice dictates per-site OR sharing across function
heres what happens: - header fail seen before, time to dig more
dyndbg: get: header fail on 100-3231 dyndbg: changed drivers/gpu/drm/i915/gvt/mmio_context.c:3231 [i915]restore_context_mmio_for_inhibit =prg dyndbg: get: header fail on 101-1412 dyndbg: changed drivers/gpu/drm/i915/gvt/cmd_parser.c:1412 [i915]init_cmd_table =prg dyndbg: get: header fail on 102-1409 dyndbg: changed drivers/gpu/drm/i915/gvt/cmd_parser.c:1409 [i915]gen8_check_mi_display_flip =prg dyndbg: get: header fail on 103-761 dyndbg: changed drivers/gpu/drm/i915/gvt/cmd_parser.c:761 [i915]gen8_check_mi_display_flip =prg dyndbg: get: header fail on 104-760 dyndbg: changed drivers/gpu/drm/i915/gvt/cmd_parser.c:760 [i915]parser_exec_state_dump =prg Signed-off-by: Jim Cromie <jim.cromie@gmail.com> --- include/linux/dynamic_debug.h | 10 ++++++--- lib/dynamic_debug.c | 42 ++++++++++++++++++++++++++++++++++- 2 files changed, 48 insertions(+), 4 deletions(-)
diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h index fe70dda704d2..300fd0eed66f 100644 --- a/include/linux/dynamic_debug.h +++ b/include/linux/dynamic_debug.h @@ -64,18 +64,22 @@ struct _ddebug { #define _DPRINTK_FLAGS_INCL_FUNCNAME (1<<2) #define _DPRINTK_FLAGS_INCL_LINENO (1<<3) #define _DPRINTK_FLAGS_INCL_TID (1<<4) -#define _DPRINTK_FLAGS_DELETE_SITE (1<<7) /* drop site info to save ram */ - #define _DPRINTK_FLAGS_INCL_ANY \ (_DPRINTK_FLAGS_INCL_MODNAME | _DPRINTK_FLAGS_INCL_FUNCNAME |\ _DPRINTK_FLAGS_INCL_LINENO | _DPRINTK_FLAGS_INCL_TID) +#define _DPRINTK_FLAGS_ONCE (1<<5) /* print once flag */ +#define _DPRINTK_FLAGS_PRINTED (1<<6) /* print once state */ +#define _DPRINTK_FLAGS_RATELIMITED (1<<7) +#define _DPRINTK_FLAGS_GROUPED (1<<8) /* manipulate as a group */ +#define _DPRINTK_FLAGS_DELETE_SITE (1<<9) /* drop site info to save ram */ + #if defined DEBUG #define _DPRINTK_FLAGS_DEFAULT _DPRINTK_FLAGS_PRINT #else #define _DPRINTK_FLAGS_DEFAULT 0 #endif - unsigned int flags:8; + unsigned int flags:11; #ifdef CONFIG_JUMP_LABEL union { diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c index 66b48f1cb2d0..a81461b58f6e 100644 --- a/lib/dynamic_debug.c +++ b/lib/dynamic_debug.c @@ -86,13 +86,17 @@ static inline const char *trim_prefix(const char *path) return path + skip; } -static struct { unsigned flag:8; char opt_char; } opt_array[] = { +static struct { unsigned flag:11; char opt_char; } opt_array[] = { { _DPRINTK_FLAGS_PRINT, 'p' }, { _DPRINTK_FLAGS_INCL_MODNAME, 'm' }, { _DPRINTK_FLAGS_INCL_FUNCNAME, 'f' }, { _DPRINTK_FLAGS_INCL_LINENO, 'l' }, { _DPRINTK_FLAGS_INCL_TID, 't' }, { _DPRINTK_FLAGS_NONE, '_' }, + { _DPRINTK_FLAGS_ONCE, 'o' }, + { _DPRINTK_FLAGS_PRINTED, 'P' }, + { _DPRINTK_FLAGS_RATELIMITED, 'r' }, + { _DPRINTK_FLAGS_GROUPED, 'g' }, { _DPRINTK_FLAGS_DELETE_SITE, 'D' }, }; @@ -728,6 +732,30 @@ static inline char *dynamic_emit_prefix(struct _ddebug *desc, char *buf) return buf; } +/* test print-once or ratelimited conditions */ +static bool is_onced_or_limited(struct _ddebug *descriptor) +{ + if (descriptor->flags & _DPRINTK_FLAGS_ONCE && + descriptor->flags & _DPRINTK_FLAGS_RATELIMITED) + pr_info(" ONCE & RATELIMITED together is nonsense\n"); + + if (descriptor->flags & _DPRINTK_FLAGS_ONCE) { + if (descriptor->flags & _DPRINTK_FLAGS_PRINTED) { + v3pr_info(" would suppress print once\n"); + // return true; + } + descriptor->flags |= _DPRINTK_FLAGS_PRINTED; + // return false; // wanna see rate stuff + } + /* test rate-limits */ + if (descriptor->flags & _DPRINTK_FLAGS_RATELIMITED) { + v3pr_info("todo: fetch RLstate{%s}\n", + descriptor->flags & _DPRINTK_FLAGS_GROUPED + ? "grouped" : "solo"); + } + return false; +} + void __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...) { va_list args; @@ -737,6 +765,9 @@ void __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...) BUG_ON(!descriptor); BUG_ON(!fmt); + if (is_onced_or_limited(descriptor)) + return; + va_start(args, fmt); vaf.fmt = fmt; @@ -757,6 +788,9 @@ void __dynamic_dev_dbg(struct _ddebug *descriptor, BUG_ON(!descriptor); BUG_ON(!fmt); + if (is_onced_or_limited(descriptor)) + return; + va_start(args, fmt); vaf.fmt = fmt; @@ -788,6 +822,9 @@ void __dynamic_netdev_dbg(struct _ddebug *descriptor, BUG_ON(!descriptor); BUG_ON(!fmt); + if (is_onced_or_limited(descriptor)) + return; + va_start(args, fmt); vaf.fmt = fmt; @@ -824,6 +861,9 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor, struct va_format vaf; va_list args; + if (is_onced_or_limited(descriptor)) + return; + va_start(args, fmt); vaf.fmt = fmt; -- 2.31.1
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