Get kernel profiling on SMP systems closer to working by replacing the
mcount spin mutex with a very simple non-recursive spinlock implemented using atomic operations.
This commit is contained in:
John Baldwin
parent
797c3dba25
commit
25142c5ea1
@ -325,7 +325,7 @@ static void release_aps(void *dummy);
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struct mtx imen_mtx;
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/* lock region used by kernel profiling */
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struct mtx mcount_mtx;
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int mcount_lock;
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#ifdef USE_COMLOCK
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/* locks com (tty) data/hardware accesses: a FASTINTR() */
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@ -335,12 +335,6 @@ struct mtx com_mtx;
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static void
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init_locks(void)
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{
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/*
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* XXX The mcount mutex probably needs to be statically initialized,
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* since it will be used even in the function calls that get us to this
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* point.
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*/
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mtx_init(&mcount_mtx, "mcount", MTX_DEF);
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#ifdef USE_COMLOCK
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mtx_init(&com_mtx, "com", MTX_SPIN);
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@ -325,7 +325,7 @@ static void release_aps(void *dummy);
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struct mtx imen_mtx;
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/* lock region used by kernel profiling */
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struct mtx mcount_mtx;
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int mcount_lock;
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#ifdef USE_COMLOCK
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/* locks com (tty) data/hardware accesses: a FASTINTR() */
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@ -335,12 +335,6 @@ struct mtx com_mtx;
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static void
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init_locks(void)
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{
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/*
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* XXX The mcount mutex probably needs to be statically initialized,
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* since it will be used even in the function calls that get us to this
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* point.
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*/
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mtx_init(&mcount_mtx, "mcount", MTX_DEF);
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#ifdef USE_COMLOCK
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mtx_init(&com_mtx, "com", MTX_SPIN);
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@ -325,7 +325,7 @@ static void release_aps(void *dummy);
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struct mtx imen_mtx;
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/* lock region used by kernel profiling */
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struct mtx mcount_mtx;
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int mcount_lock;
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#ifdef USE_COMLOCK
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/* locks com (tty) data/hardware accesses: a FASTINTR() */
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@ -335,12 +335,6 @@ struct mtx com_mtx;
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static void
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init_locks(void)
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{
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/*
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* XXX The mcount mutex probably needs to be statically initialized,
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* since it will be used even in the function calls that get us to this
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* point.
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*/
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mtx_init(&mcount_mtx, "mcount", MTX_DEF);
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#ifdef USE_COMLOCK
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mtx_init(&com_mtx, "com", MTX_SPIN);
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@ -64,10 +64,11 @@
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#else
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#define MCOUNT_DECL(s) u_long s;
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#ifdef SMP
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#define MCOUNT_ENTER(s) { s = read_eflags(); \
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__asm __volatile("cli" : : : "memory"); \
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mtx_lock(&mcount_mtx); }
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#define MCOUNT_EXIT(s) { mtx_unlock(&mcount_mtx); write_eflags(s); }
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#define MCOUNT_ENTER(s) { s = read_eflags(); disable_intr(); \
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while (!atomic_cmpset_acq_int(&mcount_lock, 0, 1) \
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/* nothing */ ; }
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#define MCOUNT_EXIT(s) { atomic_store_rel_int(&mcount_lock, 0); \
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write_eflags(s); }
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#else
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#define MCOUNT_ENTER(s) { s = read_eflags(); disable_intr(); }
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#define MCOUNT_EXIT(s) (write_eflags(s))
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@ -325,7 +325,7 @@ static void release_aps(void *dummy);
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struct mtx imen_mtx;
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/* lock region used by kernel profiling */
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struct mtx mcount_mtx;
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int mcount_lock;
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#ifdef USE_COMLOCK
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/* locks com (tty) data/hardware accesses: a FASTINTR() */
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@ -335,12 +335,6 @@ struct mtx com_mtx;
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static void
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init_locks(void)
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{
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/*
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* XXX The mcount mutex probably needs to be statically initialized,
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* since it will be used even in the function calls that get us to this
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* point.
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*/
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mtx_init(&mcount_mtx, "mcount", MTX_DEF);
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#ifdef USE_COMLOCK
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mtx_init(&com_mtx, "com", MTX_SPIN);
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@ -325,7 +325,7 @@ static void release_aps(void *dummy);
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struct mtx imen_mtx;
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/* lock region used by kernel profiling */
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struct mtx mcount_mtx;
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int mcount_lock;
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#ifdef USE_COMLOCK
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/* locks com (tty) data/hardware accesses: a FASTINTR() */
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@ -335,12 +335,6 @@ struct mtx com_mtx;
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static void
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init_locks(void)
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{
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/*
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* XXX The mcount mutex probably needs to be statically initialized,
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* since it will be used even in the function calls that get us to this
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* point.
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*/
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mtx_init(&mcount_mtx, "mcount", MTX_DEF);
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#ifdef USE_COMLOCK
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mtx_init(&com_mtx, "com", MTX_SPIN);
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@ -325,7 +325,7 @@ static void release_aps(void *dummy);
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struct mtx imen_mtx;
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/* lock region used by kernel profiling */
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struct mtx mcount_mtx;
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int mcount_lock;
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#ifdef USE_COMLOCK
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/* locks com (tty) data/hardware accesses: a FASTINTR() */
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@ -335,12 +335,6 @@ struct mtx com_mtx;
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static void
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init_locks(void)
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{
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/*
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* XXX The mcount mutex probably needs to be statically initialized,
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* since it will be used even in the function calls that get us to this
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* point.
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*/
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mtx_init(&mcount_mtx, "mcount", MTX_DEF);
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#ifdef USE_COMLOCK
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mtx_init(&com_mtx, "com", MTX_SPIN);
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@ -64,10 +64,11 @@
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#else
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#define MCOUNT_DECL(s) u_long s;
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#ifdef SMP
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#define MCOUNT_ENTER(s) { s = read_eflags(); \
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__asm __volatile("cli" : : : "memory"); \
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mtx_lock(&mcount_mtx); }
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#define MCOUNT_EXIT(s) { mtx_unlock(&mcount_mtx); write_eflags(s); }
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#define MCOUNT_ENTER(s) { s = read_eflags(); disable_intr(); \
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while (!atomic_cmpset_acq_int(&mcount_lock, 0, 1) \
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/* nothing */ ; }
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#define MCOUNT_EXIT(s) { atomic_store_rel_int(&mcount_lock, 0); \
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write_eflags(s); }
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#else
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#define MCOUNT_ENTER(s) { s = read_eflags(); disable_intr(); }
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#define MCOUNT_EXIT(s) (write_eflags(s))
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