diff options
Diffstat (limited to 'sysdeps/unix/sysv/linux/x86/elision-conf.c')
| -rw-r--r-- | sysdeps/unix/sysv/linux/x86/elision-conf.c | 74 |
1 files changed, 67 insertions, 7 deletions
diff --git a/sysdeps/unix/sysv/linux/x86/elision-conf.c b/sysdeps/unix/sysv/linux/x86/elision-conf.c index 673b0005a7..7e9fbf9382 100644 --- a/sysdeps/unix/sysv/linux/x86/elision-conf.c +++ b/sysdeps/unix/sysv/linux/x86/elision-conf.c @@ -22,6 +22,11 @@ #include <elision-conf.h> #include <unistd.h> +#if HAVE_TUNABLES +# define TUNABLE_NAMESPACE elision +#endif +#include <elf/dl-tunables.h> + /* Reasonable initial tuning values, may be revised in the future. This is a conservative initial value. */ @@ -48,21 +53,76 @@ struct elision_config __elision_aconf = pthread_mutex_lock(). Disabled for suid programs. Only used when elision is available. */ -int __pthread_force_elision attribute_hidden; +int __pthread_force_elision attribute_hidden = 0; + +#if HAVE_TUNABLES +static inline void +__always_inline +do_set_elision_enable (int32_t elision_enable) +{ + /* Enable elision if it's avaliable in hardware. It's not necessary to check + if __libc_enable_secure isn't enabled since elision_enable will be set + according to the default, which is disabled. */ + if (elision_enable == 1) + __pthread_force_elision = HAS_CPU_FEATURE (RTM) ? 1 : 0; +} + +/* The pthread->elision_enable tunable is 0 or 1 indicating that elision + should be disabled or enabled respectively. The feature will only be used + if it's supported by the hardware. */ -/* Initialize elison. */ +void +TUNABLE_CALLBACK (set_elision_enable) (tunable_val_t *valp) +{ + int32_t elision_enable = (int32_t) valp->numval; + do_set_elision_enable (elision_enable); +} + +#define TUNABLE_CALLBACK_FNDECL(__name, __type) \ +static inline void \ +__always_inline \ +do_set_elision_ ## __name (__type value) \ +{ \ + __elision_aconf.__name = value; \ +} \ +void \ +TUNABLE_CALLBACK (set_elision_ ## __name) (tunable_val_t *valp) \ +{ \ + __type value = (__type) (valp)->numval; \ + do_set_elision_ ## __name (value); \ +} + +TUNABLE_CALLBACK_FNDECL (skip_lock_busy, int32_t); +TUNABLE_CALLBACK_FNDECL (skip_lock_internal_abort, int32_t); +TUNABLE_CALLBACK_FNDECL (retry_try_xbegin, int32_t); +TUNABLE_CALLBACK_FNDECL (skip_trylock_internal_abort, int32_t); +#endif + +/* Initialize elision. */ static void elision_init (int argc __attribute__ ((unused)), char **argv __attribute__ ((unused)), char **environ) { - int elision_available = HAS_CPU_FEATURE (RTM); -#ifdef ENABLE_LOCK_ELISION - __pthread_force_elision = __libc_enable_secure ? 0 : elision_available; +#if HAVE_TUNABLES + /* Elision depends on tunables and must be explicitly turned on by setting + the appropriate tunable on a supported platform. */ + + TUNABLE_GET (enable, int32_t, + TUNABLE_CALLBACK (set_elision_enable)); + TUNABLE_GET (skip_lock_busy, int32_t, + TUNABLE_CALLBACK (set_elision_skip_lock_busy)); + TUNABLE_GET (skip_lock_internal_abort, int32_t, + TUNABLE_CALLBACK (set_elision_skip_lock_internal_abort)); + TUNABLE_GET (tries, int32_t, + TUNABLE_CALLBACK (set_elision_retry_try_xbegin)); + TUNABLE_GET (skip_trylock_internal_abort, int32_t, + TUNABLE_CALLBACK (set_elision_skip_trylock_internal_abort)); #endif - if (!elision_available) - __elision_aconf.retry_try_xbegin = 0; /* Disable elision on rwlocks */ + + if (!__pthread_force_elision) + __elision_aconf.retry_try_xbegin = 0; /* Disable elision on rwlocks. */ } #ifdef SHARED |