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From: Leonid Myravjev <asm@asm.pp.ru>
To: dev@dpdk.org
Cc: Leonid Myravjev <myravjev@amicon.ru>
Subject: [dpdk-dev] [PATCH] eal/rwlocks: Try read/write and relock write to read locks added.
Date: Mon, 21 May 2018 12:08:12 +0300
Message-ID: <20180521090812.27058-1-asm@asm.pp.ru> (raw)

From: Leonid Myravjev <myravjev@amicon.ru>

Signed-off-by: Leonid Myravjev <myravjev@amicon.ru>
---
 lib/librte_eal/common/include/generic/rte_rwlock.h | 61 ++++++++++++++++++++++
 1 file changed, 61 insertions(+)

diff --git a/lib/librte_eal/common/include/generic/rte_rwlock.h b/lib/librte_eal/common/include/generic/rte_rwlock.h
index 899e9bc43..11212e2b8 100644
--- a/lib/librte_eal/common/include/generic/rte_rwlock.h
+++ b/lib/librte_eal/common/include/generic/rte_rwlock.h
@@ -76,6 +76,30 @@ rte_rwlock_read_lock(rte_rwlock_t *rwl)
 }
 
 /**
+ * Try take lock a read lock.
+ *
+ * @param rwl
+ *   A pointer to a rwlock structure.
+ * @return
+ *   1 if the lock is successfully taken; 0 otherwise.
+ */
+static inline int
+rte_rwlock_read_trylock(rte_rwlock_t *rwl)
+{
+	int32_t x;
+	int success = 0;
+
+	x = rwl->cnt;
+	/* write lock is held */
+	if (x < 0)
+		return 0;
+	success = rte_atomic32_cmpset((volatile uint32_t *)&rwl->cnt, x, x + 1);
+	if (success == 0)
+		return 0;
+	return 1;
+}
+
+/**
  * Release a read lock.
  *
  * @param rwl
@@ -110,6 +134,29 @@ rte_rwlock_write_lock(rte_rwlock_t *rwl)
 					      0, -1);
 	}
 }
+/**
+ * Try take a write lock.
+ *
+ * @param rwl
+ *   A pointer to a rwlock structure.
+ * @return
+ *   1 if the lock is successfully taken; 0 otherwise.
+ */
+static inline int
+rte_rwlock_write_trylock(rte_rwlock_t *rwl)
+{
+	int32_t x;
+	int success = 0;
+
+	x = rwl->cnt;
+	/* a lock is held */
+	if (x != 0)
+		return 0;
+	success = rte_atomic32_cmpset((volatile uint32_t *)&rwl->cnt, 0, -1);
+	if (success == 0)
+		return 0;
+	return 1;
+}
 
 /**
  * Release a write lock.
@@ -124,6 +171,20 @@ rte_rwlock_write_unlock(rte_rwlock_t *rwl)
 }
 
 /**
+ * Relock write lock to read
+ *
+ * @param rwl
+ *   A pointer to a rwlock structure.
+ */
+static inline void
+rte_rwlock_write_relock_read(rte_rwlock_t *rwl)
+{
+	rte_atomic32_add((rte_atomic32_t *)(intptr_t)&rwl->cnt, 2);
+}
+
+
+
+/**
  * Try to execute critical section in a hardware memory transaction, if it
  * fails or not available take a read lock
  *
-- 
2.13.0

             reply	other threads:[~2018-05-21  9:09 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-21  9:08 Leonid Myravjev [this message]
2018-07-12 13:55 ` Thomas Monjalon
2021-03-24 21:53   ` Thomas Monjalon

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