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Message-ID: <20231013224818.3456409-22-jim.cromie@gmail.com>
Date: Fri, 13 Oct 2023 16:48:13 -0600
From: Jim Cromie <jim.cromie@...il.com>
To: linux-kernel@...r.kernel.org, jbaron@...mai.com,
gregkh@...uxfoundation.org, dri-devel@...ts.freedesktop.org,
amd-gfx@...ts.freedesktop.org, intel-gvt-dev@...ts.freedesktop.org,
intel-gfx@...ts.freedesktop.org
Cc: lb@...ihalf.com, linux@...musvillemoes.dk, joe@...ches.com,
mcgrof@...nel.org, daniel.vetter@...ll.ch, jani.nikula@...el.com,
ville.syrjala@...ux.intel.com, seanpaul@...omium.org,
robdclark@...il.com, groeck@...gle.com, yanivt@...gle.com,
bleung@...gle.com, linux-doc@...r.kernel.org,
Jim Cromie <jim.cromie@...il.com>
Subject: [PATCH v7b 21/25] dyndbg: refactor *dynamic_emit_prefix
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@...il.com>
---
fixup whitespace
---
lib/dynamic_debug.c | 39 ++++++++++++++++++++++-----------------
1 file changed, 22 insertions(+), 17 deletions(-)
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 17eefb35ac96..5825b58043a6 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -777,11 +777,28 @@ 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)
+{
+ if (desc->flags & _DPRINTK_FLAGS_INCL_MODNAME)
+ pos += snprintf(buf + pos, remaining(pos), "%s:",
+ desc->modname);
+ if (desc->flags & _DPRINTK_FLAGS_INCL_FUNCNAME)
+ pos += snprintf(buf + pos, remaining(pos), "%s:",
+ desc->function);
+ if (desc->flags & _DPRINTK_FLAGS_INCL_SOURCENAME)
+ pos += snprintf(buf + pos, remaining(pos), "%s:",
+ trim_prefix(desc->filename));
+ return pos;
+}
+
+static char *dynamic_emit_prefix(struct _ddebug *desc, char *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> ");
@@ -790,15 +807,10 @@ static char *__dynamic_emit_prefix(const struct _ddebug *desc, char *buf)
task_pid_vnr(current));
}
pos_after_tid = pos;
- if (desc->flags & _DPRINTK_FLAGS_INCL_MODNAME)
- pos += snprintf(buf + pos, remaining(pos), "%s:",
- desc->modname);
- if (desc->flags & _DPRINTK_FLAGS_INCL_FUNCNAME)
- pos += snprintf(buf + pos, remaining(pos), "%s:",
- desc->function);
- if (desc->flags & _DPRINTK_FLAGS_INCL_SOURCENAME)
- pos += snprintf(buf + pos, remaining(pos), "%s:",
- trim_prefix(desc->filename));
+
+ 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);
@@ -810,13 +822,6 @@ static char *__dynamic_emit_prefix(const struct _ddebug *desc, char *buf)
return buf;
}
-static inline 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;
-}
-
void __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...)
{
va_list args;
--
2.41.0
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