This is the mail archive of the glibc-cvs@sourceware.org mailing list for the glibc project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

GNU C Library master sources branch gentoo/2.22 updated. glibc-2.22-34-g23f12d0


This is an automated email from the git hooks/post-receive script. It was
generated because a ref change was pushed to the repository containing
the project "GNU C Library master sources".

The branch, gentoo/2.22 has been updated
       via  23f12d0a815e55ab60a0e6d973fc3f4730ca6980 (commit)
      from  b84ee767b4303b77a5a284b2d03f56c98d89263c (commit)

Those revisions listed above that are new to this repository have
not appeared on any other notification email; so we list those
revisions in full, below.

- Log -----------------------------------------------------------------
http://sourceware.org/git/gitweb.cgi?p=glibc.git;a=commitdiff;h=23f12d0a815e55ab60a0e6d973fc3f4730ca6980

commit 23f12d0a815e55ab60a0e6d973fc3f4730ca6980
Author: Paul Murphy <murphyp@linux.vnet.ibm.com>
Date:   Thu Aug 27 09:48:04 2015 -0500

    powerpc: Fix usage of elision transient failure adapt param
    
    The skip_lock_out_of_tbegin_retries adaptive parameter was
    not being used correctly, nor as described.  This prevents
    a fallback for all users of the lock if a transient abort
    occurs within the accepted number of retries.
    
    	[BZ #19174]
    	* sysdeps/powerpc/nptl/elide.h (__elide_lock): Fix usage of
    	.skip_lock_out_of_tbegin_retries.
    	* sysdeps/unix/sysv/linux/powerpc/elision-lock.c
    	(__lll_lock_elision): Likewise, and respect a value of
    	try_tbegin <= 0.
    
    (cherry picked from commit 72f1463df85a522bfd1568e47bd81371522ee358)
    
    Conflicts:
    	NEWS
    
    (cherry picked from commit cd51b1424477652cccdb83e7a95644d198fd4513)

diff --git a/sysdeps/powerpc/nptl/elide.h b/sysdeps/powerpc/nptl/elide.h
index 12171f4..2e1e443 100644
--- a/sysdeps/powerpc/nptl/elide.h
+++ b/sysdeps/powerpc/nptl/elide.h
@@ -27,7 +27,7 @@
    configurations.  Returns true if the system should retry again or false
    otherwise.  */
 static inline bool
-__get_new_count (uint8_t *adapt_count)
+__get_new_count (uint8_t *adapt_count, int attempt)
 {
   /* A persistent failure indicates that a retry will probably
      result in another failure.  Use normal locking now and
@@ -40,7 +40,7 @@ __get_new_count (uint8_t *adapt_count)
     }
   /* Same logic as above, but for a number of temporary failures in a
      a row.  */
-  else if (__elision_aconf.skip_lock_out_of_tbegin_retries > 0
+  else if (attempt <= 1 && __elision_aconf.skip_lock_out_of_tbegin_retries > 0
 	   && __elision_aconf.try_tbegin > 0)
     *adapt_count = __elision_aconf.skip_lock_out_of_tbegin_retries;
   return true;
@@ -78,7 +78,7 @@ __get_new_count (uint8_t *adapt_count)
 	      __builtin_tabort (_ABORT_LOCK_BUSY);			\
 	    }								\
 	  else								\
-	    if (!__get_new_count(&adapt_count))				\
+	    if (!__get_new_count (&adapt_count,i))			\
 	      break;							\
 	}								\
     ret;								\
diff --git a/sysdeps/unix/sysv/linux/powerpc/elision-lock.c b/sysdeps/unix/sysv/linux/powerpc/elision-lock.c
index 7f9bcc2..c6731ca 100644
--- a/sysdeps/unix/sysv/linux/powerpc/elision-lock.c
+++ b/sysdeps/unix/sysv/linux/powerpc/elision-lock.c
@@ -72,8 +72,7 @@ __lll_lock_elision (int *lock, short *adapt_count, EXTRAARG int pshared)
       goto use_lock;
     }
 
-  int try_begin = aconf.try_tbegin;
-  while (1)
+  for (int i = aconf.try_tbegin; i > 0; i--)
     {
       if (__builtin_tbegin (0))
 	{
@@ -87,21 +86,19 @@ __lll_lock_elision (int *lock, short *adapt_count, EXTRAARG int pshared)
 	  /* A persistent failure indicates that a retry will probably
 	     result in another failure.  Use normal locking now and
 	     for the next couple of calls.  */
-	  if (try_begin-- <= 0
-	      || _TEXASRU_FAILURE_PERSISTENT (__builtin_get_texasru ()))
+	  if (_TEXASRU_FAILURE_PERSISTENT (__builtin_get_texasru ()))
 	    {
 	      if (aconf.skip_lock_internal_abort > 0)
 		*adapt_count = aconf.skip_lock_internal_abort;
 	      goto use_lock;
 	    }
-	  /* Same logic as above, but for for a number of temporary failures
-	     in a row.  */
-	  else if (aconf.skip_lock_out_of_tbegin_retries > 0
-                   && aconf.try_tbegin > 0)
-	    *adapt_count = aconf.skip_lock_out_of_tbegin_retries;
 	}
      }
 
+  /* Fall back to locks for a bit if retries have been exhausted */
+  if (aconf.try_tbegin > 0 && aconf.skip_lock_out_of_tbegin_retries > 0)
+    *adapt_count = aconf.skip_lock_out_of_tbegin_retries;
+
 use_lock:
   return LLL_LOCK ((*lock), pshared);
 }

-----------------------------------------------------------------------

Summary of changes:
 sysdeps/powerpc/nptl/elide.h                   |    6 +++---
 sysdeps/unix/sysv/linux/powerpc/elision-lock.c |   15 ++++++---------
 2 files changed, 9 insertions(+), 12 deletions(-)


hooks/post-receive
-- 
GNU C Library master sources


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]