diff options
| -rw-r--r-- | sys/kern/kern_mutex.c | 2 | ||||
| -rw-r--r-- | sys/kern/sched_4bsd.c | 7 | ||||
| -rw-r--r-- | sys/kern/sched_ule.c | 27 |
3 files changed, 11 insertions, 25 deletions
diff --git a/sys/kern/kern_mutex.c b/sys/kern/kern_mutex.c index 85ca646370d8..f9c3377ce880 100644 --- a/sys/kern/kern_mutex.c +++ b/sys/kern/kern_mutex.c @@ -616,7 +616,6 @@ thread_lock_block(struct thread *td) { struct mtx *lock; - spinlock_enter(); THREAD_LOCK_ASSERT(td, MA_OWNED); lock = td->td_lock; td->td_lock = &blocked_lock; @@ -631,7 +630,6 @@ thread_lock_unblock(struct thread *td, struct mtx *new) mtx_assert(new, MA_OWNED); MPASS(td->td_lock == &blocked_lock); atomic_store_rel_ptr((volatile void *)&td->td_lock, (uintptr_t)new); - spinlock_exit(); } void diff --git a/sys/kern/sched_4bsd.c b/sys/kern/sched_4bsd.c index 99ea7b802380..bcec5b9205dd 100644 --- a/sys/kern/sched_4bsd.c +++ b/sys/kern/sched_4bsd.c @@ -920,9 +920,11 @@ sched_sleep(struct thread *td, int pri) void sched_switch(struct thread *td, struct thread *newtd, int flags) { + struct mtx *tmtx; struct td_sched *ts; struct proc *p; + tmtx = NULL; ts = td->td_sched; p = td->td_proc; @@ -931,10 +933,11 @@ sched_switch(struct thread *td, struct thread *newtd, int flags) /* * Switch to the sched lock to fix things up and pick * a new thread. + * Block the td_lock in order to avoid breaking the critical path. */ if (td->td_lock != &sched_lock) { mtx_lock_spin(&sched_lock); - thread_unlock(td); + tmtx = thread_lock_block(td); } if ((td->td_flags & TDF_NOLOAD) == 0) @@ -1004,7 +1007,7 @@ sched_switch(struct thread *td, struct thread *newtd, int flags) (*dtrace_vtime_switch_func)(newtd); #endif - cpu_switch(td, newtd, td->td_lock); + cpu_switch(td, newtd, tmtx != NULL ? tmtx : td->td_lock); lock_profile_obtain_lock_success(&sched_lock.lock_object, 0, 0, __FILE__, __LINE__); /* diff --git a/sys/kern/sched_ule.c b/sys/kern/sched_ule.c index 43c9a867ab05..f29dd95855a7 100644 --- a/sys/kern/sched_ule.c +++ b/sys/kern/sched_ule.c @@ -301,7 +301,6 @@ static int sched_pickcpu(struct thread *, int); static void sched_balance(void); static int sched_balance_pair(struct tdq *, struct tdq *); static inline struct tdq *sched_setcpu(struct thread *, int, int); -static inline struct mtx *thread_block_switch(struct thread *); static inline void thread_unblock_switch(struct thread *, struct mtx *); static struct mtx *sched_switch_migrate(struct tdq *, struct thread *, int); static int sysctl_kern_sched_topology_spec(SYSCTL_HANDLER_ARGS); @@ -1106,9 +1105,11 @@ sched_setcpu(struct thread *td, int cpu, int flags) * The hard case, migration, we need to block the thread first to * prevent order reversals with other cpus locks. */ + spinlock_enter(); thread_lock_block(td); TDQ_LOCK(tdq); thread_lock_unblock(td, TDQ_LOCKPTR(tdq)); + spinlock_exit(); return (tdq); } @@ -1715,23 +1716,6 @@ sched_unlend_user_prio(struct thread *td, u_char prio) } /* - * Block a thread for switching. Similar to thread_block() but does not - * bump the spin count. - */ -static inline struct mtx * -thread_block_switch(struct thread *td) -{ - struct mtx *lock; - - THREAD_LOCK_ASSERT(td, MA_OWNED); - lock = td->td_lock; - td->td_lock = &blocked_lock; - mtx_unlock_spin(lock); - - return (lock); -} - -/* * Handle migration from sched_switch(). This happens only for * cpu binding. */ @@ -1749,7 +1733,7 @@ sched_switch_migrate(struct tdq *tdq, struct thread *td, int flags) * not holding either run-queue lock. */ spinlock_enter(); - thread_block_switch(td); /* This releases the lock on tdq. */ + thread_lock_block(td); /* This releases the lock on tdq. */ /* * Acquire both run-queue locks before placing the thread on the new @@ -1769,7 +1753,8 @@ sched_switch_migrate(struct tdq *tdq, struct thread *td, int flags) } /* - * Release a thread that was blocked with thread_block_switch(). + * Variadic version of thread_lock_unblock() that does not assume td_lock + * is blocked. */ static inline void thread_unblock_switch(struct thread *td, struct mtx *mtx) @@ -1825,7 +1810,7 @@ sched_switch(struct thread *td, struct thread *newtd, int flags) } else { /* This thread must be going to sleep. */ TDQ_LOCK(tdq); - mtx = thread_block_switch(td); + mtx = thread_lock_block(td); tdq_load_rem(tdq, td); } /* |