struct StgClosure_ *payload[FLEXIBLE_ARRAY];
};
-/* What a stroke of luck - all our mutable closures follow the same
- * basic layout, with the mutable link field as the second field after
- * the header. This means the following structure is the supertype of
- * mutable closures.
- */
-
-typedef struct StgMutClosure_ {
- StgHeader header;
- StgWord padding;
- struct StgMutClosure_ *mut_link;
- struct StgClosure_ *payload[FLEXIBLE_ARRAY];
-} StgMutClosure;
-
typedef struct {
StgHeader header;
StgClosure *selectee;
} StgInd;
typedef struct {
- StgHeader header;
- StgClosure *indirectee;
- StgMutClosure *mut_link;
-} StgIndOldGen;
-
-typedef struct {
StgHeader header;
StgClosure *indirectee;
StgClosure *static_link;
typedef struct {
StgHeader header;
StgWord ptrs;
- StgMutClosure *mut_link; /* mutable list */
StgClosure *payload[FLEXIBLE_ARRAY];
} StgMutArrPtrs;
typedef struct {
StgHeader header;
StgClosure *var;
- StgMutClosure *mut_link;
} StgMutVar;
typedef struct _StgUpdateFrame {
typedef struct {
StgHeader header;
struct StgTSO_ *head;
- StgMutClosure *mut_link;
struct StgTSO_ *tail;
StgClosure* value;
} StgMVar;
+/* STM data structures
+ *
+ * StgTVar defines the only type that can be updated through the STM
+ * interface.
+ *
+ * Note that various optimisations may be possible in order to use less
+ * space for these data structures at the cost of more complexity in the
+ * implementation:
+ *
+ * - In StgTVar, current_value and first_wait_queue_entry could be held in
+ * the same field: if any thread is waiting then its expected_value for
+ * the tvar is the current value.
+ *
+ * - In StgTRecHeader, it might be worthwhile having separate chunks
+ * of read-only and read-write locations. This would save a
+ * new_value field in the read-only locations.
+ */
+
+typedef struct StgTVarWaitQueue_ {
+ StgHeader header;
+ struct StgTSO_ *waiting_tso;
+ struct StgTVarWaitQueue_ *next_queue_entry;
+ struct StgTVarWaitQueue_ *prev_queue_entry;
+} StgTVarWaitQueue;
+
+typedef struct {
+ StgHeader header;
+ StgClosure *current_value;
+ StgTVarWaitQueue *first_wait_queue_entry;
+} StgTVar;
+
+// new_value == expected_value for read-only accesses
+// new_value is a StgTVarWaitQueue entry when trec in state TREC_WAITING
+typedef struct {
+ StgTVar *tvar;
+ StgClosure *expected_value;
+ StgClosure *new_value;
+} TRecEntry;
+
+#define TREC_CHUNK_NUM_ENTRIES 256
+
+typedef struct StgTRecChunk_ {
+ StgHeader header;
+ struct StgTRecChunk_ *prev_chunk;
+ StgWord next_entry_idx;
+ TRecEntry entries[TREC_CHUNK_NUM_ENTRIES];
+} StgTRecChunk;
+
+typedef enum {
+ TREC_ACTIVE, // Transaction in progress, outcome undecided
+ TREC_CANNOT_COMMIT, // Transaction in progress, inconsistent writes performed
+ TREC_MUST_ABORT, // Transaction in progress, inconsistent / out of date reads
+ TREC_COMMITTED, // Transaction has committed, now updating tvars
+ TREC_ABORTED, // Transaction has aborted, now reverting tvars
+ TREC_WAITING, // Transaction currently waiting
+} TRecState;
+
+typedef struct StgTRecHeader_ {
+ StgHeader header;
+ TRecState state;
+ struct StgTRecHeader_ *enclosing_trec;
+ StgTRecChunk *current_chunk;
+} StgTRecHeader;
+
+typedef struct {
+ StgHeader header;
+ StgBool waiting;
+ StgClosure *code;
+} StgAtomicallyFrame;
+
+typedef struct {
+ StgHeader header;
+ StgClosure *handler;
+} StgCatchSTMFrame;
+
+typedef struct {
+ StgHeader header;
+ StgBool running_alt_code;
+ StgClosure *first_code;
+ StgClosure *alt_code;
+ StgTRecHeader *first_code_trec;
+} StgCatchRetryFrame;
+
#if defined(PAR) || defined(GRAN)
/*
StgBlockingQueueElement is a ``collective type'' representing the types
of closures that can be found on a blocking queue: StgTSO, StgRBHSave,
StgBlockedFetch. (StgRBHSave can only appear at the end of a blocking
queue). Logically, this is a union type, but defining another struct
- with a common layout is easier to handle in the code (same as for
- StgMutClosures).
+ with a common layout is easier to handle in the code.
Note that in the standard setup only StgTSOs can be on a blocking queue.
This is one of the main reasons for slightly different code in files
such as Schedule.c.
typedef struct StgBlockingQueueElement_ {
StgHeader header;
struct StgBlockingQueueElement_ *link; /* next elem in BQ */
- StgMutClosure *mut_link; /* next elem in mutable list */
struct StgClosure_ *payload[FLEXIBLE_ARRAY];/* contents of the closure */
} StgBlockingQueueElement;
typedef struct StgBlockingQueue_ {
StgHeader header;
struct StgBlockingQueueElement_ *blocking_queue; /* start of the BQ */
- StgMutClosure *mut_link; /* next elem in mutable list */
} StgBlockingQueue;
/* this closure is hanging at the end of a blocking queue in (see RBH.c) */
typedef struct StgRBH_ {
StgHeader header;
struct StgBlockingQueueElement_ *blocking_queue; /* start of the BQ */
- StgMutClosure *mut_link; /* next elem in mutable list */
} StgRBH;
#else
typedef struct StgBlockingQueue_ {
StgHeader header;
struct StgTSO_ *blocking_queue;
- StgMutClosure *mut_link;
} StgBlockingQueue;
#endif
typedef struct StgFetchMe_ {
StgHeader header;
globalAddr *ga; /* ptr to unique id for a closure */
- StgMutClosure *mut_link; /* next elem in mutable list */
} StgFetchMe;
/* same contents as an ordinary StgBlockingQueue */
typedef struct StgFetchMeBlockingQueue_ {
StgHeader header;
struct StgBlockingQueueElement_ *blocking_queue; /* start of the BQ */
- StgMutClosure *mut_link; /* next elem in mutable list */
} StgFetchMeBlockingQueue;
/* This is an entry in a blocking queue. It indicates a fetch request from a
typedef struct StgBlockedFetch_ {
StgHeader header;
struct StgBlockingQueueElement_ *link; /* next elem in the BQ */
- StgMutClosure *mut_link; /* next elem in mutable list */
StgClosure *node; /* node to fetch */
globalAddr ga; /* where to send the result to */
} StgBlockedFetch; /* NB: not just a ptr to a GA */
projects / ghc-hetmet.git / blobdiff