Messages in this thread Patch in this message | | | From | Nicholas Piggin <> | Subject | [PATCH v2 01/12] locking/qspinlock: remove pv_node abstraction | Date | Wed, 13 Jul 2022 17:06:53 +1000 |
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There isn't much point trying to separate struct qnode from struct pv_node when struct qnode has to know about pv_node anyway.
Acked-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> --- kernel/locking/qspinlock.c | 3 ++- kernel/locking/qspinlock_paravirt.h | 34 +++++++++++------------------ 2 files changed, 15 insertions(+), 22 deletions(-)
diff --git a/kernel/locking/qspinlock.c b/kernel/locking/qspinlock.c index 65a9a10caa6f..a0fc21d99199 100644 --- a/kernel/locking/qspinlock.c +++ b/kernel/locking/qspinlock.c @@ -82,7 +82,8 @@ struct qnode { struct mcs_spinlock mcs; #ifdef CONFIG_PARAVIRT_SPINLOCKS - long reserved[2]; + int cpu; + u8 state; #endif }; diff --git a/kernel/locking/qspinlock_paravirt.h b/kernel/locking/qspinlock_paravirt.h index e84d21aa0722..4efe00e6b441 100644 --- a/kernel/locking/qspinlock_paravirt.h +++ b/kernel/locking/qspinlock_paravirt.h @@ -47,12 +47,6 @@ enum vcpu_state { vcpu_hashed, /* = pv_hash'ed + vcpu_halted */ }; -struct pv_node { - struct mcs_spinlock mcs; - int cpu; - u8 state; -}; - /* * Hybrid PV queued/unfair lock * @@ -170,7 +164,7 @@ static __always_inline int trylock_clear_pending(struct qspinlock *lock) */ struct pv_hash_entry { struct qspinlock *lock; - struct pv_node *node; + struct qnode *node; }; #define PV_HE_PER_LINE (SMP_CACHE_BYTES / sizeof(struct pv_hash_entry)) @@ -209,7 +203,7 @@ void __init __pv_init_lock_hash(void) offset < (1 << pv_lock_hash_bits); \ offset++, he = &pv_lock_hash[(hash + offset) & ((1 << pv_lock_hash_bits) - 1)]) -static struct qspinlock **pv_hash(struct qspinlock *lock, struct pv_node *node) +static struct qspinlock **pv_hash(struct qspinlock *lock, struct qnode *node) { unsigned long offset, hash = hash_ptr(lock, pv_lock_hash_bits); struct pv_hash_entry *he; @@ -236,11 +230,11 @@ static struct qspinlock **pv_hash(struct qspinlock *lock, struct pv_node *node) BUG(); } -static struct pv_node *pv_unhash(struct qspinlock *lock) +static struct qnode *pv_unhash(struct qspinlock *lock) { unsigned long offset, hash = hash_ptr(lock, pv_lock_hash_bits); struct pv_hash_entry *he; - struct pv_node *node; + struct qnode *node; for_each_hash_entry(he, offset, hash) { if (READ_ONCE(he->lock) == lock) { @@ -264,7 +258,7 @@ static struct pv_node *pv_unhash(struct qspinlock *lock) * in a running state. */ static inline bool -pv_wait_early(struct pv_node *prev, int loop) +pv_wait_early(struct qnode *prev, int loop) { if ((loop & PV_PREV_CHECK_MASK) != 0) return false; @@ -277,9 +271,7 @@ pv_wait_early(struct pv_node *prev, int loop) */ static void pv_init_node(struct mcs_spinlock *node) { - struct pv_node *pn = (struct pv_node *)node; - - BUILD_BUG_ON(sizeof(struct pv_node) > sizeof(struct qnode)); + struct qnode *pn = (struct qnode *)node; pn->cpu = smp_processor_id(); pn->state = vcpu_running; @@ -292,8 +284,8 @@ static void pv_init_node(struct mcs_spinlock *node) */ static void pv_wait_node(struct mcs_spinlock *node, struct mcs_spinlock *prev) { - struct pv_node *pn = (struct pv_node *)node; - struct pv_node *pp = (struct pv_node *)prev; + struct qnode *pn = (struct qnode *)node; + struct qnode *pp = (struct qnode *)prev; int loop; bool wait_early; @@ -359,7 +351,7 @@ static void pv_wait_node(struct mcs_spinlock *node, struct mcs_spinlock *prev) */ static void pv_kick_node(struct qspinlock *lock, struct mcs_spinlock *node) { - struct pv_node *pn = (struct pv_node *)node; + struct qnode *pn = (struct qnode *)node; /* * If the vCPU is indeed halted, advance its state to match that of @@ -402,7 +394,7 @@ static void pv_kick_node(struct qspinlock *lock, struct mcs_spinlock *node) static u32 pv_wait_head_or_lock(struct qspinlock *lock, struct mcs_spinlock *node) { - struct pv_node *pn = (struct pv_node *)node; + struct qnode *pn = (struct qnode *)node; struct qspinlock **lp = NULL; int waitcnt = 0; int loop; @@ -492,7 +484,7 @@ pv_wait_head_or_lock(struct qspinlock *lock, struct mcs_spinlock *node) __visible void __pv_queued_spin_unlock_slowpath(struct qspinlock *lock, u8 locked) { - struct pv_node *node; + struct qnode *node; if (unlikely(locked != _Q_SLOW_VAL)) { WARN(!debug_locks_silent, @@ -517,14 +509,14 @@ __pv_queued_spin_unlock_slowpath(struct qspinlock *lock, u8 locked) node = pv_unhash(lock); /* - * Now that we have a reference to the (likely) blocked pv_node, + * Now that we have a reference to the (likely) blocked qnode, * release the lock. */ smp_store_release(&lock->locked, 0); /* * At this point the memory pointed at by lock can be freed/reused, - * however we can still use the pv_node to kick the CPU. + * however we can still use the qnode to kick the CPU. * The other vCPU may not really be halted, but kicking an active * vCPU is harmless other than the additional latency in completing * the unlock. -- 2.35.1
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