[RFC PATCH v5 01/28] dyndbg: avoid calling dyndbg_emit_prefix when it has no work
From: Jim Cromie <jim.cromie@gmail.com>
Date: 2021-05-11 18:51:24
Also in:
lkml
Subsystem:
dynamic debug, library code, the rest · Maintainers:
Jason Baron, Jim Cromie, Andrew Morton, Linus Torvalds
Wrap function in a static-inline one, which checks flags to avoid calling the function unnecessarily. And hoist its output-buffer initialization to the grand-caller, which is already allocating the buffer on the stack, and can trivially initialize it too. Signed-off-by: Jim Cromie <jim.cromie@gmail.com> --- include/linux/dynamic_debug.h | 5 +++++ lib/dynamic_debug.c | 19 ++++++++++++------- 2 files changed, 17 insertions(+), 7 deletions(-)
diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index a57ee75342cf..dce631e678dd 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h@@ -32,6 +32,11 @@ 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_INCL_ANY \ + (_DPRINTK_FLAGS_INCL_MODNAME | _DPRINTK_FLAGS_INCL_FUNCNAME |\ + _DPRINTK_FLAGS_INCL_LINENO | _DPRINTK_FLAGS_INCL_TID) + #if defined DEBUG #define _DPRINTK_FLAGS_DEFAULT _DPRINTK_FLAGS_PRINT #else
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index c70d6347afa2..ede4a491ee87 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c@@ -586,13 +586,11 @@ static int remaining(int wrote) return 0; } -static char *dynamic_emit_prefix(const struct _ddebug *desc, char *buf) +static char *__dynamic_emit_prefix(const struct _ddebug *desc, char *buf) { int pos_after_tid; int pos = 0; - *buf = '\0'; - if (desc->flags & _DPRINTK_FLAGS_INCL_TID) { if (in_interrupt()) pos += snprintf(buf + pos, remaining(pos), "<intr> ");
@@ -618,11 +616,18 @@ 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; struct va_format vaf; - char buf[PREFIX_SIZE]; + char buf[PREFIX_SIZE] = ""; BUG_ON(!descriptor); BUG_ON(!fmt);
@@ -655,7 +660,7 @@ void __dynamic_dev_dbg(struct _ddebug *descriptor, if (!dev) { printk(KERN_DEBUG "(NULL device *): %pV", &vaf); } else { - char buf[PREFIX_SIZE]; + char buf[PREFIX_SIZE] = ""; dev_printk_emit(LOGLEVEL_DEBUG, dev, "%s%s %s: %pV", dynamic_emit_prefix(descriptor, buf),
@@ -684,7 +689,7 @@ void __dynamic_netdev_dbg(struct _ddebug *descriptor, vaf.va = &args; if (dev && dev->dev.parent) { - char buf[PREFIX_SIZE]; + char buf[PREFIX_SIZE] = ""; dev_printk_emit(LOGLEVEL_DEBUG, dev->dev.parent, "%s%s %s %s%s: %pV",
@@ -720,7 +725,7 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor, vaf.va = &args; if (ibdev && ibdev->dev.parent) { - char buf[PREFIX_SIZE]; + char buf[PREFIX_SIZE] = ""; dev_printk_emit(LOGLEVEL_DEBUG, ibdev->dev.parent, "%s%s %s %s: %pV",
--
2.31.1