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Re: [PATCH] Remove __PTHREAD_MUTEX_HAVE_ELISION undefined warning

From: Stefan Liebler <stli at linux dot vnet dot ibm dot com>
To: libc-alpha at sourceware dot org
Date: Fri, 04 Apr 2014 15:09:53 +0200
Subject: Re: [PATCH] Remove __PTHREAD_MUTEX_HAVE_ELISION undefined warning
Authentication-results: sourceware.org; auth=none
References: <5332D913 dot 5050903 at linux dot vnet dot ibm dot com> <20140326163647 dot 3E42A74493 at topped-with-meat dot com> <53330F3B dot 6090009 at linux dot vnet dot ibm dot com> <20140326175007 dot D832074496 at topped-with-meat dot com> <533338C4 dot 5030107 at linux dot vnet dot ibm dot com> <533C041B dot 30800 at linux dot vnet dot ibm dot com>

Hi,

this is okay on s390. I have tested the patch with s390/s390x.
Thanks.

On 04/02/2014 02:35 PM, Adhemerval Zanella wrote:

Ping for arch maintainers.

On 26-03-2014 17:29, Adhemerval Zanella wrote:

On 26-03-2014 14:50, Roland McGrath wrote:

I don't understand what "support for 64 bits" or "support for 32 bits"
means.  OK, I've looked at bits/pthreadtypes.h so I do understand.  But it
seems pretty wrong to pretend this is a generic 32/64 sort of thing when it
is really just about the x86-private layout of pthread_mutex_t.  It seems
more proper to have bits/pthreadtypes.h just define __PTHREAD_SPINS.

That can be a separate cleanup if you want, and others may want to kibitz.
But that might involve dropping the header you're adding here, so maybe you
want to just resolve it now.

If you want to go ahead with this change, then it's OK with the other nits
above and this comment rewritten to describe concretely what the macro
means.  In actual usage so far, it doesn't actually mean anything about
elision support per se.  It just means something about how the fields of
pthread_mutex_t are structured and hence what the initializer must look like.
If that's all it's for, it should be made clear.

Cleanup up the whole __PTHREAD_SPINS seems the appropriated measure.  This patch
moves the __PTHREAD_SPINS definition to arch specific header since pthread_mutex_t
layout is also arch specific and does not make sense disassociate them.
This makes the definition of __PTHREAD_MUTEX_HAVE_ELISION not required.

--

	* nptl/sysdeps/pthread/pthread.h (__PTHREAD_MUTEX_HAVE_ELISION):
	Remove macro usage.
	(__PTHREAD_SPINS): Move definition to ...
	* nptl/sysdeps/unix/sysv/linux/powerpc/bits/pthreadtypes.h
	(__PTHREAD_SPINS): ... here.
	* nptl/sysdeps/unix/sysv/linux/s390/bits/pthreadtypes.h
	(__PTHREAD_SPIN): Likewise.
	* nptl/sysdeps/unix/sysv/linux/sh/bits/pthreadtypes.h
	(__PTHREAD_SPIN): Likewise.
	* nptl/sysdeps/unix/sysv/linux/sparc/bits/pthreadtypes.h
	(__PTHREAD_SPIN): Likewise.
	* nptl/sysdeps/unix/sysv/linux/x86/bits/pthreadtypes.h
	(__PTHREAD_SPIN): Likewise.
	* sysdeps/unix/sysv/linux/aarch64/nptl/bits/pthreadtypes.h
	(__PTHREAD_SPIN): Likewise.
	* sysdeps/unix/sysv/linux/alpha/nptl/bits/pthreadtypes.h
	(__PTHREAD_SPIN): Likewise.
	* sysdeps/unix/sysv/linux/arm/nptl/bits/pthreadtypes.h
	(__PTHREAD_SPIN): Likewise.
	* sysdeps/unix/sysv/linux/ia64/nptl/bits/pthreadtypes.h
	(__PTHREAD_SPIN): Likewise.
	* sysdeps/unix/sysv/linux/m68k/nptl/bits/pthreadtypes.h
	(__PTHREAD_SPIN): Likewise.
	* sysdeps/unix/sysv/linux/microblaze/nptl/bits/pthreadtypes.h
	(__PTHREAD_SPIN): Likewise.
	* sysdeps/unix/sysv/linux/mips/nptl/bits/pthreadtypes.h
	(__PTHREAD_SPIN): Likewise.
	* sysdeps/unix/sysv/linux/tile/nptl/bits/pthreadtypes.h
	(__PTHREAD_SPIN): Likewise.

ports/ChangeLog.hppa
	* ports/sysdeps/unix/sysv/linux/hppa/nptl/bits/pthreadtypes.h
	(__PTHREAD_SPIN): Moved defintion from pthread.h.

---

diff --git a/nptl/sysdeps/pthread/pthread.h b/nptl/sysdeps/pthread/pthread.h
index 1e0c5dc..40a3e21 100644
--- a/nptl/sysdeps/pthread/pthread.h
+++ b/nptl/sysdeps/pthread/pthread.h
@@ -82,15 +82,6 @@ enum
  #endif


-/* Mutex initializers.  */
-#if __PTHREAD_MUTEX_HAVE_ELISION == 1 /* 64bit layout.  */
-#define __PTHREAD_SPINS 0, 0
-#elif __PTHREAD_MUTEX_HAVE_ELISION == 2 /* 32bit layout.  */
-#define __PTHREAD_SPINS { 0, 0 }
-#else
-#define __PTHREAD_SPINS 0
-#endif
-
  #ifdef __PTHREAD_MUTEX_HAVE_PREV
  # define PTHREAD_MUTEX_INITIALIZER \
    { { 0, 0, 0, 0, 0, __PTHREAD_SPINS, { 0, 0 } } }
diff --git a/nptl/sysdeps/unix/sysv/linux/powerpc/bits/pthreadtypes.h b/nptl/sysdeps/unix/sysv/linux/powerpc/bits/pthreadtypes.h
index 71bd3ae..20e5fc0 100644
--- a/nptl/sysdeps/unix/sysv/linux/powerpc/bits/pthreadtypes.h
+++ b/nptl/sysdeps/unix/sysv/linux/powerpc/bits/pthreadtypes.h
@@ -106,6 +106,9 @@ typedef union
    long int __align;
  } pthread_mutex_t;

+/* Mutex __spins initilizer used by PTHREAD_MUTEX_INITIALIZER.  */
+#define __PTHREAD_SPINS 0
+
  typedef union
  {
    char __size[__SIZEOF_PTHREAD_MUTEXATTR_T];
diff --git a/nptl/sysdeps/unix/sysv/linux/s390/bits/pthreadtypes.h b/nptl/sysdeps/unix/sysv/linux/s390/bits/pthreadtypes.h
index 23a1698..716f151 100644
--- a/nptl/sysdeps/unix/sysv/linux/s390/bits/pthreadtypes.h
+++ b/nptl/sysdeps/unix/sysv/linux/s390/bits/pthreadtypes.h
@@ -20,8 +20,6 @@

  #include <bits/wordsize.h>

-# define __PTHREAD_MUTEX_HAVE_ELISION   0
-
  #if __WORDSIZE == 64
  # define __SIZEOF_PTHREAD_ATTR_T 56
  # define __SIZEOF_PTHREAD_MUTEX_T 40
@@ -107,6 +105,9 @@ typedef union
    long int __align;
  } pthread_mutex_t;

+/* Mutex __spins initilizer used by PTHREAD_MUTEX_INITIALIZER.  */
+#define __PTHREAD_SPINS 0
+
  typedef union
  {
    char __size[__SIZEOF_PTHREAD_MUTEXATTR_T];
diff --git a/nptl/sysdeps/unix/sysv/linux/sh/bits/pthreadtypes.h b/nptl/sysdeps/unix/sysv/linux/sh/bits/pthreadtypes.h
index e42d94e..f92958c 100644
--- a/nptl/sysdeps/unix/sysv/linux/sh/bits/pthreadtypes.h
+++ b/nptl/sysdeps/unix/sysv/linux/sh/bits/pthreadtypes.h
@@ -77,6 +77,9 @@ typedef union
    long int __align;
  } pthread_mutex_t;

+/* Mutex __spins initilizer used by PTHREAD_MUTEX_INITIALIZER.  */
+#define __PTHREAD_SPINS 0
+
  typedef union
  {
    char __size[__SIZEOF_PTHREAD_MUTEXATTR_T];
diff --git a/nptl/sysdeps/unix/sysv/linux/sparc/bits/pthreadtypes.h b/nptl/sysdeps/unix/sysv/linux/sparc/bits/pthreadtypes.h
index be615b6..7b9edf2 100644
--- a/nptl/sysdeps/unix/sysv/linux/sparc/bits/pthreadtypes.h
+++ b/nptl/sysdeps/unix/sysv/linux/sparc/bits/pthreadtypes.h
@@ -106,6 +106,9 @@ typedef union
    long int __align;
  } pthread_mutex_t;

+/* Mutex __spins initilizer used by PTHREAD_MUTEX_INITIALIZER.  */
+#define __PTHREAD_SPINS 0
+
  typedef union
  {
    char __size[__SIZEOF_PTHREAD_MUTEXATTR_T];
diff --git a/nptl/sysdeps/unix/sysv/linux/x86/bits/pthreadtypes.h b/nptl/sysdeps/unix/sysv/linux/x86/bits/pthreadtypes.h
index 28e5144..0ca10f2 100644
--- a/nptl/sysdeps/unix/sysv/linux/x86/bits/pthreadtypes.h
+++ b/nptl/sysdeps/unix/sysv/linux/x86/bits/pthreadtypes.h
@@ -105,7 +105,8 @@ typedef union
      short __elision;
      __pthread_list_t __list;
  # define __PTHREAD_MUTEX_HAVE_PREV	1
-# define __PTHREAD_MUTEX_HAVE_ELISION   1
+/* Mutex __spins initilizer used by PTHREAD_MUTEX_INITIALIZER.  */
+# define __PTHREAD_SPINS             0, 0
  #else
      unsigned int __nusers;
      __extension__ union
@@ -116,7 +117,7 @@ typedef union
  	short __elision;
  # define __spins d.__espins
  # define __elision d.__elision
-# define __PTHREAD_MUTEX_HAVE_ELISION   2
+# define __PTHREAD_SPINS         { 0, 0 }
        } d;
        __pthread_slist_t __list;
      };
diff --git a/ports/sysdeps/unix/sysv/linux/hppa/nptl/bits/pthreadtypes.h b/ports/sysdeps/unix/sysv/linux/hppa/nptl/bits/pthreadtypes.h
index deec4da..621895b 100644
--- a/ports/sysdeps/unix/sysv/linux/hppa/nptl/bits/pthreadtypes.h
+++ b/ports/sysdeps/unix/sysv/linux/hppa/nptl/bits/pthreadtypes.h
@@ -94,6 +94,9 @@ typedef union
    long int __align;
  } pthread_mutex_t;

+/* Mutex __spins initilizer used by PTHREAD_MUTEX_INITIALIZER.  */
+#define __PTHREAD_SPINS 0
+
  typedef union
  {
    char __size[__SIZEOF_PTHREAD_MUTEXATTR_T];
diff --git a/sysdeps/unix/sysv/linux/aarch64/nptl/bits/pthreadtypes.h b/sysdeps/unix/sysv/linux/aarch64/nptl/bits/pthreadtypes.h
index f11eeab..76b94b4 100644
--- a/sysdeps/unix/sysv/linux/aarch64/nptl/bits/pthreadtypes.h
+++ b/sysdeps/unix/sysv/linux/aarch64/nptl/bits/pthreadtypes.h
@@ -74,6 +74,9 @@ typedef union
    long int __align;
  } pthread_mutex_t;

+/* Mutex __spins initilizer used by PTHREAD_MUTEX_INITIALIZER.  */
+#define __PTHREAD_SPINS 0
+
  typedef union
  {
    char __size[__SIZEOF_PTHREAD_MUTEXATTR_T];
diff --git a/sysdeps/unix/sysv/linux/alpha/nptl/bits/pthreadtypes.h b/sysdeps/unix/sysv/linux/alpha/nptl/bits/pthreadtypes.h
index 6f85eae..c633c6d 100644
--- a/sysdeps/unix/sysv/linux/alpha/nptl/bits/pthreadtypes.h
+++ b/sysdeps/unix/sysv/linux/alpha/nptl/bits/pthreadtypes.h
@@ -73,6 +73,9 @@ typedef union
    long int __align;
  } pthread_mutex_t;

+/* Mutex __spins initilizer used by PTHREAD_MUTEX_INITIALIZER.  */
+#define __PTHREAD_SPINS 0
+
  typedef union
  {
    char __size[__SIZEOF_PTHREAD_MUTEXATTR_T];
diff --git a/sysdeps/unix/sysv/linux/arm/nptl/bits/pthreadtypes.h b/sysdeps/unix/sysv/linux/arm/nptl/bits/pthreadtypes.h
index 26edce5..0a0af56 100644
--- a/sysdeps/unix/sysv/linux/arm/nptl/bits/pthreadtypes.h
+++ b/sysdeps/unix/sysv/linux/arm/nptl/bits/pthreadtypes.h
@@ -77,6 +77,9 @@ typedef union
    long int __align;
  } pthread_mutex_t;

+/* Mutex __spins initilizer used by PTHREAD_MUTEX_INITIALIZER.  */
+#define __PTHREAD_SPINS 0
+
  typedef union
  {
    char __size[__SIZEOF_PTHREAD_MUTEXATTR_T];
diff --git a/sysdeps/unix/sysv/linux/ia64/nptl/bits/pthreadtypes.h b/sysdeps/unix/sysv/linux/ia64/nptl/bits/pthreadtypes.h
index b77b80a..49969bb 100644
--- a/sysdeps/unix/sysv/linux/ia64/nptl/bits/pthreadtypes.h
+++ b/sysdeps/unix/sysv/linux/ia64/nptl/bits/pthreadtypes.h
@@ -74,6 +74,9 @@ typedef union
    long int __align;
  } pthread_mutex_t;

+/* Mutex __spins initilizer used by PTHREAD_MUTEX_INITIALIZER.  */
+#define __PTHREAD_SPINS 0
+
  typedef union
  {
    char __size[__SIZEOF_PTHREAD_MUTEXATTR_T];
diff --git a/sysdeps/unix/sysv/linux/m68k/nptl/bits/pthreadtypes.h b/sysdeps/unix/sysv/linux/m68k/nptl/bits/pthreadtypes.h
index 283f240..b21f5f8 100644
--- a/sysdeps/unix/sysv/linux/m68k/nptl/bits/pthreadtypes.h
+++ b/sysdeps/unix/sysv/linux/m68k/nptl/bits/pthreadtypes.h
@@ -77,6 +77,9 @@ typedef union
    long int __align;
  } pthread_mutex_t;

+/* Mutex __spins initilizer used by PTHREAD_MUTEX_INITIALIZER.  */
+#define __PTHREAD_SPINS 0
+
  typedef union
  {
    char __size[__SIZEOF_PTHREAD_MUTEXATTR_T];
diff --git a/sysdeps/unix/sysv/linux/microblaze/nptl/bits/pthreadtypes.h b/sysdeps/unix/sysv/linux/microblaze/nptl/bits/pthreadtypes.h
index ca053e3..d4c5600 100644
--- a/sysdeps/unix/sysv/linux/microblaze/nptl/bits/pthreadtypes.h
+++ b/sysdeps/unix/sysv/linux/microblaze/nptl/bits/pthreadtypes.h
@@ -76,6 +76,9 @@ typedef union
    long int __align;
  } pthread_mutex_t;

+/* Mutex __spins initilizer used by PTHREAD_MUTEX_INITIALIZER.  */
+#define __PTHREAD_SPINS 0
+
  typedef union
  {
    char __size[__SIZEOF_PTHREAD_MUTEXATTR_T];
diff --git a/sysdeps/unix/sysv/linux/mips/nptl/bits/pthreadtypes.h b/sysdeps/unix/sysv/linux/mips/nptl/bits/pthreadtypes.h
index 9d9386b..712076c 100644
--- a/sysdeps/unix/sysv/linux/mips/nptl/bits/pthreadtypes.h
+++ b/sysdeps/unix/sysv/linux/mips/nptl/bits/pthreadtypes.h
@@ -106,6 +106,9 @@ typedef union
    long int __align;
  } pthread_mutex_t;

+/* Mutex __spins initilizer used by PTHREAD_MUTEX_INITIALIZER.  */
+#define __PTHREAD_SPINS 0
+
  typedef union
  {
    char __size[__SIZEOF_PTHREAD_MUTEXATTR_T];
diff --git a/sysdeps/unix/sysv/linux/tile/nptl/bits/pthreadtypes.h b/sysdeps/unix/sysv/linux/tile/nptl/bits/pthreadtypes.h
index f469352..17bb112 100644
--- a/sysdeps/unix/sysv/linux/tile/nptl/bits/pthreadtypes.h
+++ b/sysdeps/unix/sysv/linux/tile/nptl/bits/pthreadtypes.h
@@ -112,6 +112,9 @@ typedef union
    int __align;
  } pthread_mutexattr_t;

+/* Mutex __spins initilizer used by PTHREAD_MUTEX_INITIALIZER.  */
+#define __PTHREAD_SPINS 0
+

  /* Data structure for conditional variable handling.  The structure of
     the attribute type is not exposed on purpose.  */

Follow-Ups:
- Re: [PATCH] Remove __PTHREAD_MUTEX_HAVE_ELISION undefined warning
  - From: Adhemerval Zanella

References:
- Re: [PATCH] Remove __PTHREAD_MUTEX_HAVE_ELISION undefined warning
  - From: Adhemerval Zanella

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