/* -*- Mode: C; c-basic-offset:4 ; indent-tabs-mode:nil ; -*- */
/*
* (C) 2001 by Argonne National Laboratory.
* See COPYRIGHT in top-level directory.
*/
#ifndef MPIR_REFCOUNT_POBJ_H_INCLUDED
#define MPIR_REFCOUNT_POBJ_H_INCLUDED
/* define a type for the completion counter */
#include "opa_primitives.h"
typedef OPA_int_t MPIR_cc_t;
/* implies no barrier, since this routine should only be used for request
* initialization */
static inline void MPIR_cc_set(MPIR_cc_t * cc_ptr, int val)
{
if (val == 0) {
/* values other than 0 do not enforce any ordering, and therefore do not
* start a HB arc */
/* MT FIXME using cc_set in this way is sloppy. Sometimes the caller
* really does know that the cc value may cleared, but more likely this
* is just a hack to avoid the work of figuring out what the cc value
* currently is and decrementing it instead. */
/* barrier ensures that any state written before indicating completion is
* seen by the thread polling on the cc. If OPA adds store-release
* semantics, we can convert to that instead. */
OPA_write_barrier();
MPL_VG_ANNOTATE_HAPPENS_BEFORE(cc_ptr);
}
#if defined(MPL_VG_AVAILABLE)
/* MT subtle: store_int is actually safe to use, but Helgrind/DRD/TSan all
* view the store/load pair as a race. Using an atomic operation for the
* store side makes all three happy. DRD & TSan also support
* ANNOTATE_BENIGN_RACE, but Helgrind does not. */
OPA_swap_int(cc_ptr, val);
#else
OPA_store_int(cc_ptr, val);
#endif
}
ATTRIBUTE((unused))
static inline int MPIR_cc_is_complete(MPIR_cc_t * cc_ptr)
{
int complete;
complete = (0 == OPA_load_int(cc_ptr));
if (complete) {
MPL_VG_ANNOTATE_HAPPENS_AFTER(cc_ptr);
OPA_read_barrier();
}
return complete;
}
/* incomplete_==TRUE iff the cc > 0 after the decr */
#define MPIR_cc_decr(cc_ptr_, incomplete_) \
do { \
int ctr_; \
OPA_write_barrier(); \
MPL_VG_ANNOTATE_HAPPENS_BEFORE(cc_ptr_); \
ctr_ = OPA_fetch_and_decr_int(cc_ptr_); \
MPIR_Assert(ctr_ >= 1); \
*(incomplete_) = (ctr_ != 1); \
/* TODO check if this HA is actually necessary */ \
if (!*(incomplete_)) { \
MPL_VG_ANNOTATE_HAPPENS_AFTER(cc_ptr_); \
} \
} while (0)
/* MT FIXME does this need a HB/HA annotation? This macro is only used for
* cancel_send right now. */
/* was_incomplete_==TRUE iff the cc==0 before the decr */
#define MPIR_cc_incr(cc_ptr_, was_incomplete_) \
do { \
*(was_incomplete_) = OPA_fetch_and_incr_int(cc_ptr_); \
} while (0)
#define MPIR_cc_get(cc_) OPA_load_int(&(cc_))
/* "publishes" the obj with handle value (handle_) via the handle pointer
* (hnd_lval_). That is, it is a version of the following statement that fixes
* memory consistency issues:
* (hnd_lval_) = (handle_);
*
* assumes that the following is always true: typeof(*hnd_lval_ptr_)==int
*/
/* This could potentially be generalized beyond MPI-handle objects, but we
* should only take that step after seeing good evidence of its use. A general
* macro (that is portable to non-gcc compilers) will need type information to
* make the appropriate volatile cast. */
/* Ideally _GLOBAL would use this too, but we don't want to count on OPA
* availability in _GLOBAL mode. Instead the GLOBAL critical section should be
* used. */
#define MPIR_OBJ_PUBLISH_HANDLE(hnd_lval_, handle_) \
do { \
if (MPIR_ThreadInfo.isThreaded) { \
/* wmb ensures all read-only object field values are seen before the */ \
/* handle value is seen at the application level */ \
OPA_write_barrier(); \
/* volatile ensures lval is not speculatively read or written */ \
*(volatile int *)&(hnd_lval_) = (handle_); \
} \
else { \
(hnd_lval_) = (handle_); \
} \
} while (0)
#endif /* MPIR_REFCOUNT_POBJ_H_INCLUDED */