current/SOURCES/glibc-2.20-ELIDE_UNLOCK-handle-disabled-lock-elision.patch


This patch disables adaptive elision on rwlocks
ELIDE_UNLOCK that get triggered on non-haswell hw :/

https://bugs.mageia.org/show_bug.cgi?id=14172

Signed-off-by: Thomas Backlund <tmb@mageia.org>

--- glibc-2.20/sysdeps/x86/elide.h      2014-09-07 11:09:09.000000000 +0300
+++ glibc-2.20.fix/sysdeps/x86/elide.h  2014-10-10 20:07:14.137285925 +0300
@@ -98,10 +98,13 @@ elision_adapt(signed char *adapt_count,
 #define ELIDE_UNLOCK(is_lock_free)             \
   ({                                           \
   int ret = 0;                                 \
-  if (is_lock_free)                            \
+  if (__elision_aconf.retry_try_xbegin > 0)    \
     {                                          \
-      _xend ();                                        \
-      ret = 1;                                 \
+      if (is_lock_free)                                \
+        {                                      \
+          _xend ();                            \
+          ret = 1;                             \
+        }                                      \
     }                                          \
   ret;                                         \
   })
1
2	This patch disables adaptive elision on rwlocks
3	ELIDE_UNLOCK that get triggered on non-haswell hw :/
4
5	https://bugs.mageia.org/show_bug.cgi?id=14172
6
7	Signed-off-by: Thomas Backlund <tmb@mageia.org>
8
9	--- glibc-2.20/sysdeps/x86/elide.h 2014-09-07 11:09:09.000000000 +0300
10	+++ glibc-2.20.fix/sysdeps/x86/elide.h 2014-10-10 20:07:14.137285925 +0300
11	@@ -98,10 +98,13 @@ elision_adapt(signed char *adapt_count,
12	#define ELIDE_UNLOCK(is_lock_free) \
13	({ \
14	int ret = 0; \
15	- if (is_lock_free) \
16	+ if (__elision_aconf.retry_try_xbegin > 0) \
17	{ \
18	- _xend (); \
19	- ret = 1; \
20	+ if (is_lock_free) \
21	+ { \
22	+ _xend (); \
23	+ ret = 1; \
24	+ } \
25	} \
26	ret; \
27	})