Refactor the split of duties between outer & inner fns.
The outer fn was previously just an inline unlikely forward to inner,
which did all the work.
Now, outer handles +t and +l flags itself, and calls inner only when
_DPRINTK_FLAGS_INCL_LOOKUP is needed.
No functional change.
But it does make the results of the inner-fn more cache-friendly
(fewer entries, reused more often):
1- no spurious [TID] or <intr> noise
2- no LINE-number to bloat the cache (avg 9 pr_debugs/fn)
3- only LOOKUP stuff
Currently LOOKUPs are descriptor-field refs but could be replaced by
accessor functions. This would allow the __dyndbg_sites section to be
de-duplicated and reclaimed; currently module, filename fields are
~90% repeated. As the accessors get more expensive, the value of
caching part of the prefix goes up.
Also change inner-fn to return count of extra chars written to the
buffer, and drop "inline" from outer, let the compiler decide. Maybe
also change name accordingly.
Signed-off-by: Jim Cromie <jim.cromie@xxxxxxxxx>
---
lib/dynamic_debug.c | 55 ++++++++++++++++++++++++---------------------
1 file changed, 30 insertions(+), 25 deletions(-)
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 17eefb35ac96..974395bf8a83 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -777,19 +777,8 @@ static int remaining(int wrote)
return 0;
}
-static char *__dynamic_emit_prefix(const struct _ddebug *desc, char *buf)
+static int __dynamic_emit_prefix(const struct _ddebug *desc, char *buf, int pos)
{
- int pos_after_tid;
- int pos = 0;
-
- if (desc->flags & _DPRINTK_FLAGS_INCL_TID) {
- if (in_interrupt())
- pos += snprintf(buf + pos, remaining(pos), "<intr> ");
- else
- pos += snprintf(buf + pos, remaining(pos), "[%d] ",
- task_pid_vnr(current));
- }
- pos_after_tid = pos;
if (desc->flags & _DPRINTK_FLAGS_INCL_MODNAME)
pos += snprintf(buf + pos, remaining(pos), "%s:",
desc->modname);
@@ -799,22 +788,38 @@ static char *__dynamic_emit_prefix(const struct _ddebug *desc, char *buf)
if (desc->flags & _DPRINTK_FLAGS_INCL_SOURCENAME)
pos += snprintf(buf + pos, remaining(pos), "%s:",
trim_prefix(desc->filename));
- if (desc->flags & _DPRINTK_FLAGS_INCL_LINENO)
- pos += snprintf(buf + pos, remaining(pos), "%d:",
- desc->lineno);
- if (pos - pos_after_tid)
- pos += snprintf(buf + pos, remaining(pos), " ");
- if (pos >= PREFIX_SIZE)
- buf[PREFIX_SIZE - 1] = '\0';
-
- return buf;
+ return pos;
}
-static inline char *dynamic_emit_prefix(struct _ddebug *desc, char *buf)
+static char *dynamic_emit_prefix(struct _ddebug *desc, char *buf)
{
- if (unlikely(desc->flags & _DPRINTK_FLAGS_INCL_ANY))
- return __dynamic_emit_prefix(desc, buf);
- return buf;
+ int pos_after_tid;
+ int pos = 0;
+
+ if (likely(!(desc->flags & _DPRINTK_FLAGS_INCL_ANY)))
+ return buf;
+
+ if (desc->flags & _DPRINTK_FLAGS_INCL_TID) {
+ if (in_interrupt())
+ pos += snprintf(buf + pos, remaining(pos), "<intr> ");
+ else
+ pos += snprintf(buf + pos, remaining(pos), "[%d] ",
+ task_pid_vnr(current));
+ }
+ pos_after_tid = pos;
+
+ if (unlikely(desc->flags & _DPRINTK_FLAGS_INCL_LOOKUP))
+ pos += __dynamic_emit_prefix(desc, buf, pos);
+
+ if (desc->flags & _DPRINTK_FLAGS_INCL_LINENO)
+ pos += snprintf(buf + pos, remaining(pos), "%d:",
+ desc->lineno);
+ if (pos - pos_after_tid)
+ pos += snprintf(buf + pos, remaining(pos), " ");
+ if (pos >= PREFIX_SIZE)
+ buf[PREFIX_SIZE - 1] = '\0';
+
+ return buf;
}
void __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...)
--
2.41.0
