new linux futex calls to manage contention

[btree] / fosterbtreee.c

diff --git a/fosterbtreee.c b/fosterbtreee.c
index c9c4ffaace9b6391a4938eab6a850fcf05817454..8d18fed9353ec1b77c51bbe2e97b34eee81b1f27 100644 (file)
--- a/fosterbtreee.c
+++ b/fosterbtreee.c
@@ -234,7 +234,7 @@ typedef struct {
        BtLatchMgr *latchmgr;           // mapped latch page from allocation page
        BtLatchSet *latchset;           // first mapped latch set from latch pages
 #ifndef unix
-       HANDLE halloc, hlatch;          // allocation and latch table handles
+       HANDLE halloc;                          // allocation and latch table handle
 #endif
 } BtMgr;
 
@@ -363,20 +363,27 @@ ushort prev;
 
   do {
 #ifdef unix
-       do prev = __sync_fetch_and_or((ushort *)latch, Mutex);
-       while( prev & Mutex );
+       while( __sync_fetch_and_or((ushort *)latch, Mutex) & Mutex )
+               sched_yield();
 #else
-       do prev = _InterlockedOr16((ushort *)latch, Mutex);
-       while( prev & Mutex );
+       while( _InterlockedOr16((ushort *)latch, Mutex) & Mutex )
+               SwitchToThread();
 #endif
 
-       //  see if exclusive request is pending, or granted
+       //  see if exclusive request is granted or pending
 
        if( prev = !(latch->exclusive | latch->pending) )
-               latch->share++;
-
-       latch->mutex = 0;
+#ifdef unix
+               __sync_fetch_and_add((ushort *)latch, Share);
+#else
+               _InterlockedExchangeAdd16 ((ushort *)latch, Share);
+#endif
 
+#ifdef unix
+       __sync_fetch_and_and ((ushort *)latch, ~Mutex);
+#else
+       _InterlockedAnd16((ushort *)latch, ~Mutex);
+#endif
        if( prev )
                return;
 #ifdef  unix
@@ -394,17 +401,24 @@ ushort prev;
 
   do {
 #ifdef  unix
-       do prev = __sync_fetch_and_or((ushort *)latch, (Pending | Mutex));
-       while( prev & Mutex );
+       while( __sync_fetch_and_or((ushort *)latch, Mutex | Pending) & Mutex )
+               sched_yield();
 #else
-       do prev = _InterlockedOr16((ushort *)latch, (Pending | Mutex));
-       while( prev & Mutex );
+       while( _InterlockedOr16((ushort *)latch, Mutex | Pending) & Mutex )
+               SwitchToThread();
 #endif
        if( prev = !(latch->share | latch->exclusive) )
-               latch->exclusive = 1, latch->pending = 0;
-
-       latch->mutex = 0;
+#ifdef unix
+               __sync_fetch_and_or((ushort *)latch, Write);
+#else
+               _InterlockedOr16((ushort *)latch, Write);
+#endif
 
+#ifdef unix
+       __sync_fetch_and_and ((ushort *)latch, ~(Mutex | Pending));
+#else
+       _InterlockedAnd16((ushort *)latch, ~(Mutex | Pending));
+#endif
        if( prev )
                return;
 #ifdef  unix
@@ -425,18 +439,26 @@ int bt_spinwritetry(BtSpinLatch *latch)
 ushort prev;
 
 #ifdef unix
-       do prev = __sync_fetch_and_or((ushort *)latch, Mutex);
-       while( prev & Mutex );
+       if( prev = __sync_fetch_and_or((ushort *)latch, Mutex), prev & Mutex )
+               return 0;
 #else
-       do prev = _InterlockedOr16((ushort *)latch, Mutex);
-       while( prev & Mutex );
+       if( prev = _InterlockedOr16((ushort *)latch, Mutex), prev & Mutex )
+               return 0;
 #endif
        //      take write access if all bits are clear
 
        if( !prev )
-               latch->exclusive = 1;
+#ifdef unix
+               __sync_fetch_and_or ((ushort *)latch, Write);
+#else
+               _InterlockedOr16((ushort *)latch, Write);
+#endif
 
-       latch->mutex = 0;
+#ifdef unix
+       __sync_fetch_and_and ((ushort *)latch, ~Mutex);
+#else
+       _InterlockedAnd16((ushort *)latch, ~Mutex);
+#endif
        return !prev;
 }
 
@@ -444,36 +466,22 @@ ushort prev;
 
 void bt_spinreleasewrite(BtSpinLatch *latch)
 {
-ushort prev;
-
 #ifdef unix
-       do prev = __sync_fetch_and_or((ushort *)latch, Mutex);
-       while( prev & Mutex );
+       __sync_fetch_and_and ((ushort *)latch, ~Write);
 #else
-       do prev = _InterlockedOr16((ushort *)latch, Mutex);
-       while( prev & Mutex );
+       _InterlockedAnd16((ushort *)latch, ~Write);
 #endif
-
-       latch->exclusive = 0;
-       latch->mutex = 0;
 }
 
 //     decrement reader count
 
 void bt_spinreleaseread(BtSpinLatch *latch)
 {
-ushort prev;
-
 #ifdef unix
-       do prev = __sync_fetch_and_or((ushort *)latch, Mutex);
-       while( prev & Mutex );
+       __sync_fetch_and_add((ushort *)latch, -Share);
 #else
-       do prev = _InterlockedOr16((ushort *)latch, Mutex);
-       while( prev & Mutex );
+       _InterlockedExchangeAdd16 ((ushort *)latch, -Share);
 #endif
-
-       latch->share--;
-       latch->mutex = 0;
 }
 
 void bt_initlockset (BtLatchSet *set)
@@ -944,23 +952,16 @@ mgrlatch:
                return bt_mgrclose (mgr), NULL;
 #else
        flag = ( mgr->mode == BT_ro ? PAGE_READONLY : PAGE_READWRITE );
-       mgr->halloc = CreateFileMapping(mgr->idx, NULL, flag, 0, mgr->page_size, NULL);
+       mgr->halloc = CreateFileMapping(mgr->idx, NULL, flag, 0, (BT_latchtable / (mgr->page_size / sizeof(BtLatchSet)) + 1 + LATCH_page) * mgr->page_size, NULL);
        if( !mgr->halloc )
                return bt_mgrclose (mgr), NULL;
 
        flag = ( mgr->mode == BT_ro ? FILE_MAP_READ : FILE_MAP_WRITE );
-       mgr->latchmgr = MapViewOfFile(mgr->halloc, flag, 0, ALLOC_page * mgr->page_size, mgr->page_size);
+       mgr->latchmgr = MapViewOfFile(mgr->halloc, flag, 0, 0, (BT_latchtable / (mgr->page_size / sizeof(BtLatchSet)) + 1 + LATCH_page) * mgr->page_size);
        if( !mgr->latchmgr )
-               return bt_mgrclose (mgr), NULL;
-       flag = ( mgr->mode == BT_ro ? PAGE_READONLY : PAGE_READWRITE );
-       mgr->hlatch = CreateFileMapping(mgr->idx, NULL, flag, 0, (mgr->latchmgr->nlatchpage + LATCH_page) * mgr->page_size, NULL);
-       if( !mgr->hlatch )
-               return bt_mgrclose (mgr), NULL;
+               return GetLastError(), bt_mgrclose (mgr), NULL;
 
-       flag = ( mgr->mode == BT_ro ? FILE_MAP_READ : FILE_MAP_WRITE );
-       mgr->latchset = MapViewOfFile(mgr->halloc, flag, 0, LATCH_page * mgr->page_size, mgr->page_size * mgr->latchmgr->nlatchpage);
-       if( !mgr->latchmgr )
-               return bt_mgrclose (mgr), NULL;
+       mgr->latchset = (void *)((char *)mgr->latchmgr + LATCH_page * mgr->page_size);
 #endif
 
 #ifdef unix