The patch titled
Kconfig.debug: Set DEBUG_MUTEX to off by default
has been removed from the -mm tree. Its filename is
kconfigdebug-set-debug_mutex-to-off-by-default.patch
This patch was probably dropped from -mm because
it has now been merged into a subsystem tree or
into Linus's tree, or because it was folded into
its parent patch in the -mm tree.
From: Tim Chen <tim.c.chen@xxxxxxxxxxxxxxx>
DEBUG_MUTEX flag is on by default in current kernel configuration.
During performance testing, we saw mutex debug functions like
mutex_debug_check_no_locks_freed (called by kfree()) is expensive as it
goes through a global list of memory areas with mutex lock and do the
checking. For benchmarks such as Volanomark and Hackbench, we have seen
more than 40% drop in performance on some platforms. We suggest to set
DEBUG_MUTEX off by default. Or at least do that later when we feel that
the mutex changes in the current code have stabilized.
Signed-off-by: Tim Chen <tim.c.chen@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
lib/Kconfig.debug | 2 +-
1 files changed, 1 insertion(+), 1 deletion(-)
diff -puN lib/Kconfig.debug~kconfigdebug-set-debug_mutex-to-off-by-default lib/Kconfig.debug
--- devel/lib/Kconfig.debug~kconfigdebug-set-debug_mutex-to-off-by-default 2006-04-18 22:20:01.000000000 -0700
+++ devel-akpm/lib/Kconfig.debug 2006-04-18 22:20:01.000000000 -0700
@@ -101,7 +101,7 @@ config DEBUG_PREEMPT
config DEBUG_MUTEXES
bool "Mutex debugging, deadlock detection"
- default y
+ default n
depends on DEBUG_KERNEL
help
This allows mutex semantics violations and mutex related deadlocks
_
Patches currently in -mm which might be from tim.c.chen@xxxxxxxxxxxxxxx are
origin.patch
-
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