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author | Paul Murphy <murphyp@linux.vnet.ibm.com> | 2015-08-27 09:48:04 -0500 |
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committer | Tulio Magno Quites Machado Filho <tuliom@linux.vnet.ibm.com> | 2015-10-27 17:27:41 -0200 |
commit | 72f1463df85a522bfd1568e47bd81371522ee358 (patch) | |
tree | a257dcbec150b619574c29326f89ee10d013891f /sysdeps/unix | |
parent | 76c5ae00284d98f1994434c570bdcde9dbc6b49e (diff) | |
download | glibc-72f1463df85a522bfd1568e47bd81371522ee358.zip glibc-72f1463df85a522bfd1568e47bd81371522ee358.tar.gz glibc-72f1463df85a522bfd1568e47bd81371522ee358.tar.bz2 |
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.
Diffstat (limited to 'sysdeps/unix')
-rw-r--r-- | sysdeps/unix/sysv/linux/powerpc/elision-lock.c | 15 |
1 files changed, 6 insertions, 9 deletions
diff --git a/sysdeps/unix/sysv/linux/powerpc/elision-lock.c b/sysdeps/unix/sysv/linux/powerpc/elision-lock.c index 3762732..4775fca 100644 --- a/sysdeps/unix/sysv/linux/powerpc/elision-lock.c +++ b/sysdeps/unix/sysv/linux/powerpc/elision-lock.c @@ -50,8 +50,7 @@ __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)) { @@ -65,21 +64,19 @@ __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); } |