diff options
| author | Nicholas Piggin <npiggin@gmail.com> | 2023-10-16 22:43:04 +1000 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2023-10-20 22:43:34 +1100 |
| commit | 1e6d5f725738fff83e1c3cbdb8547142eb8820c2 (patch) | |
| tree | 4dca22d69a72fa9ed2ae13cdf2b2c1a28c47d699 /arch/powerpc/lib/qspinlock.c | |
| parent | fcf77d44274b96a55cc74043561a4b3151b9ad24 (diff) | |
powerpc/qspinlock: Propagate sleepy if previous waiter is preempted
The sleepy (aka lock-owner-is-preempted) condition is propagated down
the queue by each waiter. If a waiter becomes preempted, it can no
longer propagate sleepy. To allow subsequent waiters to yield to the
lock owner, also check the lock owner in this case.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Tested-by: Shrikanth Hegde <sshegde@linux.vnet.ibm.com>
Reviewed-by: "Nysal Jan K.A" <nysal@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231016124305.139923-6-npiggin@gmail.com
Diffstat (limited to 'arch/powerpc/lib/qspinlock.c')
| -rw-r--r-- | arch/powerpc/lib/qspinlock.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/arch/powerpc/lib/qspinlock.c b/arch/powerpc/lib/qspinlock.c index 6bb627e90a32..c68c2bd7b853 100644 --- a/arch/powerpc/lib/qspinlock.c +++ b/arch/powerpc/lib/qspinlock.c @@ -384,7 +384,11 @@ static __always_inline bool yield_to_prev(struct qspinlock *lock, struct qnode * if (!pv_yield_propagate_owner) goto yield_prev; - if (node->sleepy) { + /* + * If the previous waiter was preempted it might not be able to + * propagate sleepy to us, so check the lock in that case too. + */ + if (node->sleepy || vcpu_is_preempted(prev_cpu)) { u32 val = READ_ONCE(lock->val); if (val & _Q_LOCKED_VAL) { |