Changeset 3679f51a in mainline for uspace/lib/c/include/futex.h

Timestamp:

2018-06-25T20:41:09Z (7 years ago)

Author:

Jiří Zárevúcky <jiri.zarevucky@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

95838f1

Parents:

d73d992

git-author:

Jiří Zárevúcky <jiri.zarevucky@…> (2018-06-25 20:30:35)

git-committer:

Jiří Zárevúcky <jiri.zarevucky@…> (2018-06-25 20:41:09)

Message:

Remove the option of RCU-upgradable futexes for now.
They complicate threading design too much.

File:

• uspace/lib/c/include/futex.h (modified) (1 diff)

uspace/lib/c/include/futex.h

@@ -42 +42 @@
 typedef struct futex {
         atomic_t val;
-#ifdef FUTEX_UPGRADABLE
-        int upgraded;
-#endif
 } futex_t;
-
 
 extern void futex_initialize(futex_t *futex, int value);
 
-#ifdef FUTEX_UPGRADABLE
-#include <rcu.h>
-
-#define FUTEX_INITIALIZE(val) {{ (val) }, 0}
-
-#define futex_lock(fut) \
-({ \
-        rcu_read_lock(); \
-        (fut)->upgraded = rcu_access(_upgrade_futexes); \
-        if ((fut)->upgraded) \
-                (void) futex_down((fut)); \
-})
-
-#define futex_trylock(fut) \
-({ \
-        rcu_read_lock(); \
-        int _upgraded = rcu_access(_upgrade_futexes); \
-        if (_upgraded) { \
-                int _acquired = futex_trydown((fut)); \
-                if (!_acquired) { \
-                        rcu_read_unlock(); \
-                } else { \
-                        (fut)->upgraded = true; \
-                } \
-                _acquired; \
-        } else { \
-                (fut)->upgraded = false; \
-                1; \
-        } \
-})
-
-#define futex_unlock(fut) \
-({ \
-        if ((fut)->upgraded) \
-                (void) futex_up((fut)); \
-        rcu_read_unlock(); \
-})
-
-extern int _upgrade_futexes;
-
-extern void futex_upgrade_all_and_wait(void);
-
-#else
-
 #define FUTEX_INITIALIZE(val) {{ (val) }}
+#define FUTEX_INITIALIZER     FUTEX_INITIALIZE(1)
 
 #define futex_lock(fut)     (void) futex_down((fut))
 #define futex_trylock(fut)  futex_trydown((fut))
 #define futex_unlock(fut)   (void) futex_up((fut))
-
-#endif
-
-#define FUTEX_INITIALIZER     FUTEX_INITIALIZE(1)
 
 /** Try to down the futex.