[haiku-commits] haiku: hrev51310 - src/system/libroot/posix/pthread headers/posix/sys headers/posix

From: jerome.duval@xxxxxxxxx
To: haiku-commits@xxxxxxxxxxxxx
Date: Thu, 27 Jul 2017 18:36:12 +0200 (CEST)

hrev51310 adds 1 changeset to branch 'master'
old head: b34aa933ed8963354d98a4e96c7b2faad5ca6e88
new head: 6c9e01265b8fe7f392ee55ff51b3bdc1c09b5b9b
overview:
http://cgit.haiku-os.org/haiku/log/?qt=range&q=6c9e01265b8f+%5Eb34aa933ed89

----------------------------------------------------------------------------

6c9e01265b8f: pthread_rwlock: use a mutex for process-private locks.

  * instead of a benaphore.
  * define PTHREAD_RWLOCK_INITIALIZER.
  * adjust Init(), Destroy(), StructureLock() and StructureUnlock().

                                   [ Jérôme Duval <jerome.duval@xxxxxxxxx> ]

----------------------------------------------------------------------------

Revision:    hrev51310
Commit:      6c9e01265b8fe7f392ee55ff51b3bdc1c09b5b9b
URL:         http://cgit.haiku-os.org/haiku/commit/?id=6c9e01265b8f
Author:      Jérôme Duval <jerome.duval@xxxxxxxxx>
Date:        Mon Jul 24 19:09:55 2017 UTC

----------------------------------------------------------------------------

3 files changed, 34 insertions(+), 18 deletions(-)
headers/posix/pthread.h                          |  2 +
headers/posix/sys/types.h                        | 10 ++---
.../libroot/posix/pthread/pthread_rwlock.cpp     | 40 +++++++++++++-------

----------------------------------------------------------------------------

diff --git a/headers/posix/pthread.h b/headers/posix/pthread.h
index 489aace..feaf8e3 100644
--- a/headers/posix/pthread.h
+++ b/headers/posix/pthread.h
@@ -80,6 +80,8 @@ extern "C" {
        { PTHREAD_MUTEX_RECURSIVE, 0, -42, -1, 0 }
#define PTHREAD_COND_INITIALIZER       \
        { 0, -42, NULL, 0, 0 }
+#define PTHREAD_RWLOCK_INITIALIZER     \
+       { 0, -1, {{0}} }

/* mutex functions */
extern int pthread_mutex_destroy(pthread_mutex_t *mutex);
diff --git a/headers/posix/sys/types.h b/headers/posix/sys/types.h
index b09aba5..64d497e 100644
--- a/headers/posix/sys/types.h
+++ b/headers/posix/sys/types.h
@@ -105,15 +105,15 @@ struct _pthread_rwlock {
        __haiku_std_int32       owner;
        union {
                struct {
-                       __haiku_std_int32       sem;
-               } shared;
-               struct {
-                       __haiku_std_int32       lock_sem;
-                       __haiku_std_int32       lock_count;
+                       __haiku_std_int32       mutex;
+                       __haiku_std_int32       unused;
                        __haiku_std_int32       reader_count;
                        __haiku_std_int32       writer_count;
                        void*                           waiters[2];
                } local;
+               struct {
+                       __haiku_std_int32       sem;
+               } shared;
        } u;
};

diff --git a/src/system/libroot/posix/pthread/pthread_rwlock.cpp
b/src/system/libroot/posix/pthread/pthread_rwlock.cpp
index 65e83be..b2470ae 100644
--- a/src/system/libroot/posix/pthread/pthread_rwlock.cpp
+++ b/src/system/libroot/posix/pthread/pthread_rwlock.cpp
@@ -12,12 +12,12 @@
#include <AutoLocker.h>
#include <libroot_lock.h>
#include <syscalls.h>
+#include <user_mutex_defs.h>
#include <user_thread.h>
#include <util/DoublyLinkedList.h>

#include "pthread_private.h"

-
#define MAX_READER_COUNT       1000000

#define RWLOCK_FLAG_SHARED     0x01
@@ -93,8 +93,8 @@ struct SharedRWLock {
struct LocalRWLock {
        uint32_t        flags;
        int32_t         owner;
-       int32_t         lock_sem;
-       int32_t         lock_count;
+       int32_t         mutex;
+       int32_t         unused;
        int32_t         reader_count;
        int32_t         writer_count;
                // Note, that reader_count and writer_count are not used the
same way.
@@ -106,33 +106,47 @@ struct LocalRWLock {
        {
                flags = 0;
                owner = -1;
-               lock_sem = create_sem(0, "pthread rwlock");
-               lock_count = 1;
+               mutex = 0;
                reader_count = 0;
                writer_count = 0;
                new(&waiters) WaiterList;

-               return lock_sem >= 0 ? B_OK : EAGAIN;
+               return B_OK;
        }

        status_t Destroy()
        {
-               if (lock_sem < 0)
-                       return B_BAD_VALUE;
-               return delete_sem(lock_sem) == B_OK ? B_OK : B_BAD_VALUE;
+               Locker locker(this);
+               if (reader_count > 0 || waiters.Head() != NULL || writer_count

0)

+                       return EBUSY;
+               return B_OK;
        }

        bool StructureLock()
        {
-               if (atomic_add((int32*)&lock_count, -1) <= 0)
-                       acquire_sem(lock_sem);
+               // Enter critical region: lock the mutex
+               int32 status = atomic_or((int32*)&mutex, B_USER_MUTEX_LOCKED);
+
+               // If already locked, call the kernel
+               if ((status & (B_USER_MUTEX_LOCKED | B_USER_MUTEX_WAITING)) !=
0) {
+                       do {
+                               status = _kern_mutex_lock((int32*)&mutex, NULL,
0, 0);
+                       } while (status == B_INTERRUPTED);
+
+                       if (status != B_OK)
+                               return false;
+               }
                return true;
        }

        void StructureUnlock()
        {
-               if (atomic_add((int32*)&lock_count, 1) < 0)
-                       release_sem(lock_sem);
+               // Exit critical region: unlock the mutex
+               int32 status = atomic_and((int32*)&mutex,
+                       ~(int32)B_USER_MUTEX_LOCKED);
+
+               if ((status & B_USER_MUTEX_WAITING) != 0)
+                       _kern_mutex_unlock((int32*)&mutex, 0);
        }

        status_t ReadLock(bigtime_t timeout)

[haiku-commits] haiku: hrev51310 - src/system/libroot/posix/pthread headers/posix/sys headers/posix

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