[PATCH v7c 18/24] dyndbg: reserve flag bit _DPRINTK_FLAGS_PREFIX_CACHED

Jim Cromie
2023-10-18T17:07:30Z

Reserve bit 7 to remember that a pr-debug callsite is/was:
- enabled, with +p
- wants a dynamic-prefix, with one+ of module:function:sourcfile
- was previously called
- was thus saved in the cache. NOT YET.

Its unclear whether any cache fetch would be faster than 2-3 field
fetches, but theres another factor; the 3 columns in the __dyndbg
section are highly redundant and compressible, but to get the
compression, we need field accessors, which will rebalance the
tradeoff.

So, for now, its just the bit reservation.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
include/linux/dynamic_debug.h | 1 +
1 file changed, 1 insertion(+)

diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index f182f95caabb..927cb14f24e0 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -38,6 +38,7 @@ struct _ddebug {
#define _DPRINTK_FLAGS_INCL_LINENO (1<<3)
#define _DPRINTK_FLAGS_INCL_TID (1<<4)
#define _DPRINTK_FLAGS_INCL_SOURCENAME (1<<5)
+#define _DPRINTK_FLAGS_PREFIX_CACHED (1<<7)

#define _DPRINTK_FLAGS_INCL_ANY \
(_DPRINTK_FLAGS_INCL_MODNAME | _DPRINTK_FLAGS_INCL_FUNCNAME |\
--
2.41.0