diff options
| -rw-r--r-- | ChangeLog | 12 | ||||
| -rw-r--r-- | NEWS | 14 | ||||
| -rw-r--r-- | sysdeps/powerpc/nptl/elide.h | 115 |
3 files changed, 82 insertions, 59 deletions
diff --git a/ChangeLog b/ChangeLog index 541b5e1afd..b955eb524c 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,15 @@ +2015-10-19 Tulio Magno Quites Machado Filho <tuliom@linux.vnet.ibm.com> + + [BZ #18743] + * sysdeps/powerpc/nptl/elide.h (__elide_lock): Move most of this + code to... + (ELIDE_LOCK): ...here. + (__get_new_count): New function with part of the code from + __elide_lock that updates the value of adapt_count after a + transaction abort. + (__elided_trylock): Moved this code to... + (ELIDE_TRYLOCK): ...here. + 2015-10-19 Mike Frysinger <vapier@gentoo.org> * configure.ac (AC_ARG_ENABLE(timezone-tools)): Tweak help phrasing. diff --git a/NEWS b/NEWS index c189bada06..1313ab25ff 100644 --- a/NEWS +++ b/NEWS @@ -14,13 +14,13 @@ Version 2.23 16517, 16519, 16520, 16521, 16620, 16734, 16973, 16985, 17118, 17243, 17244, 17250, 17441, 17787, 17886, 17887, 17905, 18084, 18086, 18240, 18265, 18370, 18421, 18480, 18525, 18595, 18589, 18610, 18618, 18647, - 18661, 18674, 18675, 18681, 18724, 18757, 18778, 18781, 18787, 18789, - 18790, 18795, 18796, 18803, 18820, 18823, 18824, 18825, 18857, 18863, - 18870, 18872, 18873, 18875, 18887, 18918, 18921, 18928, 18951, 18952, - 18953, 18956, 18961, 18966, 18967, 18969, 18970, 18977, 18980, 18981, - 18982, 18985, 19003, 19007, 19012, 19016, 19018, 19032, 19046, 19049, - 19050, 19059, 19071, 19074, 19076, 19077, 19078, 19079, 19085, 19086, - 19088, 19094, 19095, 19124, 19125, 19129, 19134, 19137. + 18661, 18674, 18675, 18681, 18724, 18743, 18757, 18778, 18781, 18787, + 18789, 18790, 18795, 18796, 18803, 18820, 18823, 18824, 18825, 18857, + 18863, 18870, 18872, 18873, 18875, 18887, 18918, 18921, 18928, 18951, + 18952, 18953, 18956, 18961, 18966, 18967, 18969, 18970, 18977, 18980, + 18981, 18982, 18985, 19003, 19007, 19012, 19016, 19018, 19032, 19046, + 19049, 19050, 19059, 19071, 19074, 19076, 19077, 19078, 19079, 19085, + 19086, 19088, 19094, 19095, 19124, 19125, 19129, 19134, 19137. * There is now a --disable-timezone-tools configure option for disabling the building and installing of the timezone related utilities (zic, zdump, and diff --git a/sysdeps/powerpc/nptl/elide.h b/sysdeps/powerpc/nptl/elide.h index 389f5a5e9e..12171f45dc 100644 --- a/sysdeps/powerpc/nptl/elide.h +++ b/sysdeps/powerpc/nptl/elide.h @@ -23,67 +23,78 @@ # include <htm.h> # include <elision-conf.h> -/* Returns true if the lock defined by is_lock_free as elided. - ADAPT_COUNT is a pointer to per-lock state variable. */ - +/* Get the new value of adapt_count according to the elision + configurations. Returns true if the system should retry again or false + otherwise. */ static inline bool -__elide_lock (uint8_t *adapt_count, int is_lock_free) +__get_new_count (uint8_t *adapt_count) { - if (*adapt_count > 0) + /* 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 (_TEXASRU_FAILURE_PERSISTENT (__builtin_get_texasru ())) { - (*adapt_count)--; + if (__elision_aconf.skip_lock_internal_abort > 0) + *adapt_count = __elision_aconf.skip_lock_internal_abort; return false; } - - for (int i = __elision_aconf.try_tbegin; i > 0; i--) - { - if (__builtin_tbegin (0)) - { - if (is_lock_free) - return true; - /* Lock was busy. */ - __builtin_tabort (_ABORT_LOCK_BUSY); - } - else - { - /* 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 (_TEXASRU_FAILURE_PERSISTENT (__builtin_get_texasru ())) - { - if (__elision_aconf.skip_lock_internal_abort > 0) - *adapt_count = __elision_aconf.skip_lock_internal_abort; - break; - } - /* 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 - && __elision_aconf.try_tbegin > 0) - *adapt_count = __elision_aconf.skip_lock_out_of_tbegin_retries; - } - } - - return false; + /* 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 + && __elision_aconf.try_tbegin > 0) + *adapt_count = __elision_aconf.skip_lock_out_of_tbegin_retries; + return true; } -# define ELIDE_LOCK(adapt_count, is_lock_free) \ - __elide_lock (&(adapt_count), is_lock_free) - - -static inline bool -__elide_trylock (uint8_t *adapt_count, int is_lock_free, int write) -{ - if (__elision_aconf.try_tbegin > 0) - { - if (write) - __builtin_tabort (_ABORT_NESTED_TRYLOCK); - return __elide_lock (adapt_count, is_lock_free); - } - return false; -} +/* CONCURRENCY NOTES: + + The evaluation of the macro expression is_lock_free encompasses one or + more loads from memory locations that are concurrently modified by other + threads. For lock elision to work, this evaluation and the rest of the + critical section protected by the lock must be atomic because an + execution with lock elision must be equivalent to an execution in which + the lock would have been actually acquired and released. Therefore, we + evaluate is_lock_free inside of the transaction that represents the + critical section for which we want to use lock elision, which ensures + the atomicity that we require. */ + +/* Returns 0 if the lock defined by is_lock_free was elided. + ADAPT_COUNT is a per-lock state variable. */ +# define ELIDE_LOCK(adapt_count, is_lock_free) \ + ({ \ + int ret = 0; \ + if (adapt_count > 0) \ + (adapt_count)--; \ + else \ + for (int i = __elision_aconf.try_tbegin; i > 0; i--) \ + { \ + if (__builtin_tbegin (0)) \ + { \ + if (is_lock_free) \ + { \ + ret = 1; \ + break; \ + } \ + __builtin_tabort (_ABORT_LOCK_BUSY); \ + } \ + else \ + if (!__get_new_count(&adapt_count)) \ + break; \ + } \ + ret; \ + }) # define ELIDE_TRYLOCK(adapt_count, is_lock_free, write) \ - __elide_trylock (&(adapt_count), is_lock_free, write) + ({ \ + int ret = 0; \ + if (__elision_aconf.try_tbegin > 0) \ + { \ + if (write) \ + __builtin_tabort (_ABORT_NESTED_TRYLOCK); \ + ret = ELIDE_LOCK (adapt_count, is_lock_free); \ + } \ + ret; \ + }) static inline bool |