Changeset 22580 in vbox

Timestamp:

Aug 30, 2009 8:38:49 PM (15 years ago)

Author:

vboxsync

Message:

Runtime/spinlock-r0drv-freebsd:

Replace spin mutexes with our own implementation.
Spin mutexes are always disabling interrupts which
is not what we always want here

File:

• trunk/src/VBox/Runtime/r0drv/freebsd/spinlock-r0drv-freebsd.c (modified) (8 diffs)

trunk/src/VBox/Runtime/r0drv/freebsd/spinlock-r0drv-freebsd.c

@@ -33 +33 @@
 *******************************************************************************/
 #include "the-freebsd-kernel.h"
+#include "internal/iprt.h"
 
 #include <iprt/spinlock.h>
@@ -39 +40 @@
 #include <iprt/assert.h>
 #include <iprt/asm.h>
+#include <iprt/thread.h>
+#include <iprt/mp.h>
 
 #include "internal/magics.h"
@@ -53 +56 @@
     /** Spinlock magic value (RTSPINLOCK_MAGIC). */
     uint32_t volatile   u32Magic;
-    /** A FreeBSD spinlock. (mtx can be both sleep and spin lock.) */
-    struct mtx          Mtx;
+    /** The spinlock. */
+    uint32_t volatile   fLocked;
+    /** Reserved to satisfy compile assertion below. */
+    uint32_t            uReserved;
+#ifdef RT_MORE_STRICT
+    /** The idAssertCpu variable before acquring the lock for asserting after
+     *  releasing the spinlock. */
+    RTCPUID volatile    idAssertCpu;
+    /** The CPU that owns the lock. */
+    RTCPUID volatile    idCpuOwner;
+#endif
 } RTSPINLOCKINTERNAL, *PRTSPINLOCKINTERNAL;
 
@@ -63 +75 @@
      * Allocate.
      */
+    RT_ASSERT_PREEMPTIBLE();
     AssertCompile(sizeof(RTSPINLOCKINTERNAL) > sizeof(void *));
     PRTSPINLOCKINTERNAL pSpinlockInt = (PRTSPINLOCKINTERNAL)RTMemAllocZ(sizeof(*pSpinlockInt));
@@ -72 +85 @@
      */
     pSpinlockInt->u32Magic = RTSPINLOCK_MAGIC;
-    mtx_init(&pSpinlockInt->Mtx, "IPRT Spinlock", NULL, MTX_SPIN);
+    pSpinlockInt->fLocked  = 0;
     *pSpinlock = pSpinlockInt;
     return VINF_SUCCESS;
@@ -83 +96 @@
      * Validate input.
      */
+    RT_ASSERT_INTS_ON();
     PRTSPINLOCKINTERNAL pSpinlockInt = (PRTSPINLOCKINTERNAL)Spinlock;
     if (!pSpinlockInt)
@@ -94 +108 @@
      */
     ASMAtomicIncU32(&pSpinlockInt->u32Magic);
-    mtx_destroy(&pSpinlockInt->Mtx);
     RTMemFree(pSpinlockInt);
     return VINF_SUCCESS;
@@ -105 +118 @@
     AssertPtr(pSpinlockInt);
     Assert(pSpinlockInt->u32Magic == RTSPINLOCK_MAGIC);
+    RT_ASSERT_PREEMPT_CPUID_VAR();
+
+    for (;;)
+    {
+        pTmp->uFlags = ASMGetFlags();
+        ASMIntDisable();
+        critical_enter();
+
+        for (int c = 50; c > 0; c--)
+            if (ASMAtomicCmpXchgU32(&pSpinlockInt->fLocked, 1, 0))
+            {
+                RT_ASSERT_PREEMPT_CPUID_SPIN_ACQUIRED(pSpinlockInt);
+                return;
+            }
+            else
+                cpu_spinwait();
+
+        /* Enable interrupts while we sleep. */
+        ASMSetFlags(pTmp->uFlags);
+        critical_exit();
+        DELAY(1);
+    }
+}
+
+
+RTDECL(void) RTSpinlockReleaseNoInts(RTSPINLOCK Spinlock, PRTSPINLOCKTMP pTmp)
+{
+    PRTSPINLOCKINTERNAL pSpinlockInt = (PRTSPINLOCKINTERNAL)Spinlock;
+    RT_ASSERT_PREEMPT_CPUID_SPIN_RELEASE_VARS();
+
+    AssertPtr(pSpinlockInt);
+    Assert(pSpinlockInt->u32Magic == RTSPINLOCK_MAGIC);
+    RT_ASSERT_PREEMPT_CPUID_SPIN_RELEASE(pSpinlockInt);
     NOREF(pTmp);
 
-    mtx_lock_spin(&pSpinlockInt->Mtx);
-}
-
-
-RTDECL(void) RTSpinlockReleaseNoInts(RTSPINLOCK Spinlock, PRTSPINLOCKTMP pTmp)
-{
-    PRTSPINLOCKINTERNAL pSpinlockInt = (PRTSPINLOCKINTERNAL)Spinlock;
-    AssertPtr(pSpinlockInt);
-    Assert(pSpinlockInt->u32Magic == RTSPINLOCK_MAGIC);
+    if (!ASMAtomicCmpXchgU32(&pSpinlockInt->fLocked, 0, 1))
+        AssertMsgFailed(("Spinlock %p was not locked!\n", pSpinlockInt));
+    ASMSetFlags(pTmp->uFlags);
+
+    critical_exit();
+}
+
+
+RTDECL(void) RTSpinlockAcquire(RTSPINLOCK Spinlock, PRTSPINLOCKTMP pTmp)
+{
+    PRTSPINLOCKINTERNAL pSpinlockInt = (PRTSPINLOCKINTERNAL)Spinlock;
+    RT_ASSERT_PREEMPT_CPUID_VAR();
+    AssertPtr(pSpinlockInt);
+    Assert(pSpinlockInt->u32Magic == RTSPINLOCK_MAGIC);
+
     NOREF(pTmp);
 
-    mtx_unlock_spin(&pSpinlockInt->Mtx);
-}
-
-
-RTDECL(void) RTSpinlockAcquire(RTSPINLOCK Spinlock, PRTSPINLOCKTMP pTmp)
-{
-    PRTSPINLOCKINTERNAL pSpinlockInt = (PRTSPINLOCKINTERNAL)Spinlock;
-    AssertPtr(pSpinlockInt);
-    Assert(pSpinlockInt->u32Magic == RTSPINLOCK_MAGIC);
+    for (;;)
+    {
+        critical_enter();
+        for (int c = 50; c > 0; c--)
+            if (ASMAtomicCmpXchgU32(&pSpinlockInt->fLocked, 1, 0))
+            {
+                RT_ASSERT_PREEMPT_CPUID_SPIN_ACQUIRED(pSpinlockInt);
+                return;
+            }
+            else
+                cpu_spinwait();
+
+        critical_exit();
+        DELAY(1);
+    }
+}
+
+
+RTDECL(void) RTSpinlockRelease(RTSPINLOCK Spinlock, PRTSPINLOCKTMP pTmp)
+{
+    PRTSPINLOCKINTERNAL pSpinlockInt = (PRTSPINLOCKINTERNAL)Spinlock;
+    RT_ASSERT_PREEMPT_CPUID_SPIN_RELEASE_VARS();
+
+    AssertPtr(pSpinlockInt);
+    Assert(pSpinlockInt->u32Magic == RTSPINLOCK_MAGIC);
+    RT_ASSERT_PREEMPT_CPUID_SPIN_RELEASE(pSpinlockInt);
+
     NOREF(pTmp);
 
-    mtx_lock_spin(&pSpinlockInt->Mtx);
-}
-
-
-RTDECL(void) RTSpinlockRelease(RTSPINLOCK Spinlock, PRTSPINLOCKTMP pTmp)
-{
-    PRTSPINLOCKINTERNAL pSpinlockInt = (PRTSPINLOCKINTERNAL)Spinlock;
-    AssertPtr(pSpinlockInt);
-    Assert(pSpinlockInt->u32Magic == RTSPINLOCK_MAGIC);
-    NOREF(pTmp);
-
-    mtx_unlock_spin(&pSpinlockInt->Mtx);
-}
-
+    if (!ASMAtomicCmpXchgU32(&pSpinlockInt->fLocked, 0, 1))
+        AssertMsgFailed(("Spinlock %p was not locked!\n", pSpinlockInt));
+
+    critical_exit();
+}
+