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/*
* %CopyrightBegin%
*
* Copyright Ericsson AB 2012. All Rights Reserved.
*
* The contents of this file are subject to the Erlang Public License,
* Version 1.1, (the "License"); you may not use this file except in
* compliance with the License. You should have received a copy of the
* Erlang Public License along with this software. If not, it can be
* retrieved online at http://www.erlang.org/.
*
* Software distributed under the License is distributed on an "AS IS"
* basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
* the License for the specific language governing rights and limitations
* under the License.
*
* %CopyrightEnd%
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include "code_ix.h"
#include "global.h"
#include "beam_catches.h"
#if 0
# define CIX_TRACE(text) erts_fprintf(stderr, "CIX_TRACE: " text " act=%u load=%u\r\n", erts_active_code_ix(), erts_staging_code_ix())
#else
# define CIX_TRACE(text)
#endif
erts_smp_atomic32_t the_active_code_index;
erts_smp_atomic32_t the_staging_code_index;
static int the_code_ix_lock = 0;
struct code_ix_queue_item {
Process *p;
struct code_ix_queue_item* next;
};
static struct code_ix_queue_item* the_code_ix_queue = NULL;
static erts_smp_mtx_t the_code_ix_queue_lock;
void erts_code_ix_init(void)
{
/* We start emulator by initializing preloaded modules
* single threaded with active and staging set both to zero.
* Preloading is finished by a commit that will set things straight.
*/
erts_smp_atomic32_init_nob(&the_active_code_index, 0);
erts_smp_atomic32_init_nob(&the_staging_code_index, 0);
erts_smp_mtx_init(&the_code_ix_queue_lock, "code_ix_queue");
CIX_TRACE("init");
}
void erts_start_staging_code_ix(void)
{
beam_catches_start_staging();
export_start_staging();
module_start_staging();
erts_start_staging_ranges();
CIX_TRACE("start");
}
void erts_commit_staging_code_ix(void)
{
beam_catches_end_staging(1);
export_end_staging(1);
module_end_staging(1);
erts_end_staging_ranges(1);
{
ErtsCodeIndex ix;
export_write_lock();
ix = erts_staging_code_ix();
erts_smp_atomic32_set_nob(&the_active_code_index, ix);
ix = (ix + 1) % ERTS_NUM_CODE_IX;
erts_smp_atomic32_set_nob(&the_staging_code_index, ix);
export_write_unlock();
}
CIX_TRACE("commit");
}
void erts_abort_staging_code_ix(void)
{
beam_catches_end_staging(0);
export_end_staging(0);
module_end_staging(0);
erts_end_staging_ranges(0);
CIX_TRACE("abort");
}
/* Try lock code_ix
* Calller _must_ yield if we return 0
*/
int erts_try_lock_code_ix(Process* c_p)
{
int success;
erts_smp_mtx_lock(&the_code_ix_queue_lock);
success = !the_code_ix_lock;
if (success) {
the_code_ix_lock = 1;
}
else { /* Already locked */
struct code_ix_queue_item* qitem;
qitem = erts_alloc(ERTS_ALC_T_CODE_IX_LOCK_Q, sizeof(*qitem));
qitem->p = c_p;
erts_smp_proc_inc_refc(c_p);
qitem->next = the_code_ix_queue;
the_code_ix_queue = qitem;
erts_suspend(c_p, ERTS_PROC_LOCK_MAIN, NULL);
}
erts_smp_mtx_unlock(&the_code_ix_queue_lock);
return success;
}
/* Unlock code_ix (resume all waiters)
*/
void erts_unlock_code_ix()
{
erts_smp_mtx_lock(&the_code_ix_queue_lock);
while (the_code_ix_queue != NULL) { /* unleash the entire herd */
struct code_ix_queue_item* qitem = the_code_ix_queue;
erts_smp_proc_lock(qitem->p, ERTS_PROC_LOCK_STATUS);
if (!ERTS_PROC_IS_EXITING(qitem->p)) {
erts_resume(qitem->p, ERTS_PROC_LOCK_STATUS);
}
erts_smp_proc_unlock(qitem->p, ERTS_PROC_LOCK_STATUS);
the_code_ix_queue = qitem->next;
erts_smp_proc_dec_refc(qitem->p);
erts_free(ERTS_ALC_T_CODE_IX_LOCK_Q, qitem);
}
the_code_ix_lock = 0;
erts_smp_mtx_unlock(&the_code_ix_queue_lock);
}
#ifdef ERTS_ENABLE_LOCK_CHECK
int erts_is_code_ix_locked(void)
{
return the_code_ix_lock;
}
#endif
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