diff options
| -rw-r--r-- | sys/conf/NOTES | 6 | ||||
| -rw-r--r-- | sys/conf/options | 1 | ||||
| -rw-r--r-- | sys/kern/kern_mutex.c | 4 |
3 files changed, 11 insertions, 0 deletions
diff --git a/sys/conf/NOTES b/sys/conf/NOTES index 53e13ef..0f37fcc 100644 --- a/sys/conf/NOTES +++ b/sys/conf/NOTES @@ -173,6 +173,12 @@ options SMP # Symmetric MultiProcessor Kernel # to disable it. options NO_ADAPTIVE_MUTEXES +# ADAPTIVE_GIANT causes the Giant lock to also be made adaptive when +# running without NO_ADAPTIVE_MUTEXES. Normally, because Giant is assumed +# to be held for extended periods, contention on Giant will cause a thread +# to sleep rather than spinning. +options ADAPTIVE_GIANT + # MUTEX_NOINLINE forces mutex operations to call functions to perform each # operation rather than inlining the simple cases. This can be used to # shrink the size of the kernel text segment. Note that this behavior is diff --git a/sys/conf/options b/sys/conf/options index 63fb9b5..ef15023 100644 --- a/sys/conf/options +++ b/sys/conf/options @@ -56,6 +56,7 @@ KDB_TRACE opt_kdb.h KDB_UNATTENDED opt_kdb.h # Miscellaneous options. +ADAPTIVE_GIANT opt_adaptive_mutexes.h NO_ADAPTIVE_MUTEXES opt_adaptive_mutexes.h ALQ CODA_COMPAT_5 opt_coda.h diff --git a/sys/kern/kern_mutex.c b/sys/kern/kern_mutex.c index c6f7b3e..507df8a 100644 --- a/sys/kern/kern_mutex.c +++ b/sys/kern/kern_mutex.c @@ -509,7 +509,11 @@ _mtx_lock_sleep(struct mtx *m, int opts, const char *file, int line) * CPU, spin instead of blocking. */ owner = (struct thread *)(v & MTX_FLAGMASK); +#ifdef ADAPTIVE_GIANT + if (TD_IS_RUNNING(owner)) { +#else if (m != &Giant && TD_IS_RUNNING(owner)) { +#endif turnstile_release(&m->mtx_object); while (mtx_owner(m) == owner && TD_IS_RUNNING(owner)) { #if defined(__i386__) || defined(__amd64__) |
