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powerpc/qspinlock: Add spinlock contention tracepoint 

Add a lock contention tracepoint in the queued spinlock slowpath.
Also add the __lockfunc annotation so that in_lock_functions()
works as expected.

Signed-off-by: Nysal Jan K.A. <nysal@linux.ibm.com>
Reviewed-by: Shrikanth Hegde <sshegde@linux.ibm.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/20250731061856.1858898-1-nysal@linux.ibm.com
This commit is contained in:
Nysal Jan K.A. 2025-07-31 11:48:53 +05:30 committed by Madhavan Srinivasan
parent 74db6cc331
commit 4f61d54d22
1 changed files with 10 additions and 9 deletions
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19
arch/powerpc/lib/qspinlock.c
View File

@ -9,6 +9,7 @@
#include <linux/sched/clock.h> #include <linux/sched/clock.h>
#include <asm/qspinlock.h> #include <asm/qspinlock.h>
#include <asm/paravirt.h> #include <asm/paravirt.h>
#include <trace/events/lock.h>
#define MAX_NODES 4 #define MAX_NODES 4
@ -708,26 +709,26 @@ static __always_inline void queued_spin_lock_mcs_queue(struct qspinlock *lock, b
qnodesp->count--; qnodesp->count--;
} }
void queued_spin_lock_slowpath(struct qspinlock *lock) void __lockfunc queued_spin_lock_slowpath(struct qspinlock *lock)
{ {
trace_contention_begin(lock, LCB_F_SPIN);
/* /*
* This looks funny, but it induces the compiler to inline both * This looks funny, but it induces the compiler to inline both
* sides of the branch rather than share code as when the condition * sides of the branch rather than share code as when the condition
* is passed as the paravirt argument to the functions. * is passed as the paravirt argument to the functions.
*/ */
if (IS_ENABLED(CONFIG_PARAVIRT_SPINLOCKS) && is_shared_processor()) { if (IS_ENABLED(CONFIG_PARAVIRT_SPINLOCKS) && is_shared_processor()) {
if (try_to_steal_lock(lock, true)) { if (try_to_steal_lock(lock, true))
spec_barrier(); spec_barrier();
return; else
} queued_spin_lock_mcs_queue(lock, true);
queued_spin_lock_mcs_queue(lock, true);
} else { } else {
if (try_to_steal_lock(lock, false)) { if (try_to_steal_lock(lock, false))
spec_barrier(); spec_barrier();
return; else
} queued_spin_lock_mcs_queue(lock, false);
queued_spin_lock_mcs_queue(lock, false);
} }
trace_contention_end(lock, 0);
} }
EXPORT_SYMBOL(queued_spin_lock_slowpath); EXPORT_SYMBOL(queued_spin_lock_slowpath);