-/* Copyright (C) 1996,1997,2000,2001, 2004, 2006 Free Software Foundation, Inc.
+/* Copyright (C) 1996,1997,2000,2001, 2004, 2006, 2007, 2008 Free Software Foundation, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
#include <stdio.h>
#include <string.h>
+#include <assert.h>
#include "libguile/_scm.h"
#include "libguile/print.h"
#define DYNAMIC_STATE_NEXT_LOC(x) SCM_SMOB_OBJECT_2_LOC(x)
#define SET_DYNAMIC_STATE_NEXT(x, y) SCM_SET_SMOB_OBJECT_2((x), (y))
-/* Weak lists of all dynamic states and all fluids.
- */
-static SCM all_dynamic_states = SCM_EOL;
-static SCM all_fluids = SCM_EOL;
-/* Make sure that all states have the right size. This must be called
- while fluid_admin_mutex is held.
-*/
+\f
+/* Grow STATE so that it can hold up to ALLOCATED_FLUIDS_NUM fluids. */
static void
-resize_all_states ()
+grow_dynamic_state (SCM state)
{
- SCM new_vectors, state;
-
- /* Replacing the vector of a dynamic state must be done atomically:
- the old values must be copied into the new vector and the new
- vector must be installed without someone modifying the old vector
- concurrently. Since accessing a fluid should be lock-free, we
- need to put all threads to sleep when replacing a vector.
- However, when being single threaded, it is best not to do much.
- Therefore, we allocate the new vectors before going single
- threaded.
- */
-
- new_vectors = SCM_EOL;
- for (state = all_dynamic_states; !scm_is_null (state);
- state = DYNAMIC_STATE_NEXT (state))
- new_vectors = scm_cons (scm_c_make_vector (allocated_fluids_len,
- SCM_BOOL_F),
- new_vectors);
-
- scm_i_thread_put_to_sleep ();
- for (state = all_dynamic_states; !scm_is_null (state);
- state = DYNAMIC_STATE_NEXT (state))
- {
- SCM old_fluids = DYNAMIC_STATE_FLUIDS (state);
- SCM new_fluids = SCM_CAR (new_vectors);
- size_t i, old_len = SCM_SIMPLE_VECTOR_LENGTH (old_fluids);
-
- for (i = 0; i < old_len; i++)
- SCM_SIMPLE_VECTOR_SET (new_fluids, i,
- SCM_SIMPLE_VECTOR_REF (old_fluids, i));
- SET_DYNAMIC_STATE_FLUIDS (state, new_fluids);
- new_vectors = SCM_CDR (new_vectors);
- }
- scm_i_thread_wake_up ();
-}
+ SCM new_fluids;
+ SCM old_fluids = DYNAMIC_STATE_FLUIDS (state);
+ size_t i, new_len, old_len = SCM_SIMPLE_VECTOR_LENGTH (old_fluids);
-/* This is called during GC, that is, while being single threaded.
- See next_fluid_num for a discussion why it is safe to access
- allocated_fluids here.
- */
-static void *
-scan_dynamic_states_and_fluids (void *dummy1 SCM_UNUSED,
- void *dummy2 SCM_UNUSED,
- void *dummy3 SCM_UNUSED)
-{
- SCM *statep, *fluidp;
+ retry:
+ new_len = allocated_fluids_num;
+ new_fluids = scm_c_make_vector (new_len, SCM_BOOL_F);
- /* Scan all fluids and deallocate the unmarked ones.
- */
- fluidp = &all_fluids;
- while (!scm_is_null (*fluidp))
+ scm_i_pthread_mutex_lock (&fluid_admin_mutex);
+ if (new_len != allocated_fluids_num)
{
- if (!SCM_GC_MARK_P (*fluidp))
- {
- allocated_fluids_num -= 1;
- allocated_fluids[FLUID_NUM (*fluidp)] = 0;
- *fluidp = FLUID_NEXT (*fluidp);
- }
- else
- fluidp = FLUID_NEXT_LOC (*fluidp);
+ /* We lost the race. */
+ scm_i_pthread_mutex_unlock (&fluid_admin_mutex);
+ goto retry;
}
- /* Scan all dynamic states and remove the unmarked ones. The live
- ones are updated for unallocated fluids.
- */
- statep = &all_dynamic_states;
- while (!scm_is_null (*statep))
- {
- if (!SCM_GC_MARK_P (*statep))
- *statep = DYNAMIC_STATE_NEXT (*statep);
- else
- {
- SCM fluids = DYNAMIC_STATE_FLUIDS (*statep);
- size_t len, i;
-
- len = SCM_SIMPLE_VECTOR_LENGTH (fluids);
- for (i = 0; i < len && i < allocated_fluids_len; i++)
- if (allocated_fluids[i] == 0)
- SCM_SIMPLE_VECTOR_SET (fluids, i, SCM_BOOL_F);
-
- statep = DYNAMIC_STATE_NEXT_LOC (*statep);
- }
- }
+ assert (allocated_fluids_num > old_len);
- return NULL;
-}
+ for (i = 0; i < old_len; i++)
+ SCM_SIMPLE_VECTOR_SET (new_fluids, i,
+ SCM_SIMPLE_VECTOR_REF (old_fluids, i));
+ SET_DYNAMIC_STATE_FLUIDS (state, new_fluids);
-static size_t
-fluid_free (SCM fluid)
-{
- /* The real work is done in scan_dynamic_states_and_fluids. We can
- not touch allocated_fluids etc here since a smob free routine can
- be run at any time, in any thread.
- */
- return 0;
+ scm_i_pthread_mutex_unlock (&fluid_admin_mutex);
}
static int
}
else
{
- /* During the following call, the GC might run and elements of
- allocated_fluids might bet set to zero. Also,
- allocated_fluids and allocated_fluids_len are used to scan
- all dynamic states during GC. Thus we need to make sure that
- no GC can run while updating these two variables.
- */
-
- char *new_allocated_fluids =
+ /* Grow the vector of allocated fluids. */
+ /* FIXME: Since we use `scm_malloc ()', ALLOCATED_FLUIDS is scanned by
+ the GC; therefore, all fluids remain reachable for the entire
+ program lifetime. Hopefully this is not a problem in practice. */
+ char *prev_allocated_fluids;
+ char *new_allocated_fluids =
scm_malloc (allocated_fluids_len + FLUID_GROW);
/* Copy over old values and initialize rest. GC can not run
memcpy (new_allocated_fluids, allocated_fluids, allocated_fluids_len);
memset (new_allocated_fluids + allocated_fluids_len, 0, FLUID_GROW);
n = allocated_fluids_len;
+
+ prev_allocated_fluids = allocated_fluids;
+
+ /* Update the vector of allocated fluids. Dynamic states will
+ eventually be lazily grown to accomodate the new value of
+ ALLOCATED_FLUIDS_LEN in `fluid-ref' and `fluid-set!'. */
allocated_fluids = new_allocated_fluids;
allocated_fluids_len += FLUID_GROW;
-
- /* Now allocated_fluids and allocated_fluids_len are valid again
- and we can allow GCs to occur.
- */
- resize_all_states ();
+
+ if (prev_allocated_fluids != NULL)
+ free (prev_allocated_fluids);
}
allocated_fluids_num += 1;
SCM_NEWSMOB2 (fluid, tc16_fluid,
(scm_t_bits) next_fluid_num (), SCM_UNPACK (SCM_EOL));
- /* The GC must not run until the fluid is properly entered into the
- list.
- */
- scm_i_scm_pthread_mutex_lock (&fluid_admin_mutex);
- SET_FLUID_NEXT (fluid, all_fluids);
- all_fluids = fluid;
- scm_i_pthread_mutex_unlock (&fluid_admin_mutex);
-
return fluid;
}
#undef FUNC_NAME
return IS_FLUID (obj);
}
-size_t
-scm_i_fluid_num (SCM fluid)
-{
- return FLUID_NUM (fluid);
-}
+
SCM_DEFINE (scm_fluid_ref, "fluid-ref", 1, 0, 0,
(SCM fluid),
SCM fluids = DYNAMIC_STATE_FLUIDS (SCM_I_CURRENT_THREAD->dynamic_state);
SCM_VALIDATE_FLUID (1, fluid);
+
+ if (SCM_UNLIKELY (FLUID_NUM (fluid) >= SCM_SIMPLE_VECTOR_LENGTH (fluids)))
+ {
+ /* We should only get there when the current thread's dynamic state
+ turns out to be too small compared to the set of currently allocated
+ fluids. */
+ assert (SCM_SIMPLE_VECTOR_LENGTH (fluids) < allocated_fluids_num);
+
+ /* Lazily grow the current thread's dynamic state. */
+ grow_dynamic_state (SCM_I_CURRENT_THREAD->dynamic_state);
+
+ fluids = DYNAMIC_STATE_FLUIDS (SCM_I_CURRENT_THREAD->dynamic_state);
+ }
+
return SCM_SIMPLE_VECTOR_REF (fluids, FLUID_NUM (fluid));
}
#undef FUNC_NAME
-SCM
-scm_i_fast_fluid_ref (size_t n)
-{
- SCM fluids = DYNAMIC_STATE_FLUIDS (SCM_I_CURRENT_THREAD->dynamic_state);
- return SCM_SIMPLE_VECTOR_REF (fluids, n);
-}
-
SCM_DEFINE (scm_fluid_set_x, "fluid-set!", 2, 0, 0,
(SCM fluid, SCM value),
"Set the value associated with @var{fluid} in the current dynamic root.")
SCM fluids = DYNAMIC_STATE_FLUIDS (SCM_I_CURRENT_THREAD->dynamic_state);
SCM_VALIDATE_FLUID (1, fluid);
+
+ if (SCM_UNLIKELY (FLUID_NUM (fluid) >= SCM_SIMPLE_VECTOR_LENGTH (fluids)))
+ {
+ /* We should only get there when the current thread's dynamic state
+ turns out to be too small compared to the set of currently allocated
+ fluids. */
+ assert (SCM_SIMPLE_VECTOR_LENGTH (fluids) < allocated_fluids_num);
+
+ /* Lazily grow the current thread's dynamic state. */
+ grow_dynamic_state (SCM_I_CURRENT_THREAD->dynamic_state);
+
+ fluids = DYNAMIC_STATE_FLUIDS (SCM_I_CURRENT_THREAD->dynamic_state);
+ }
+
SCM_SIMPLE_VECTOR_SET (fluids, FLUID_NUM (fluid), value);
return SCM_UNSPECIFIED;
}
#undef FUNC_NAME
-void
-scm_i_fast_fluid_set_x (size_t n, SCM value)
-{
- SCM fluids = DYNAMIC_STATE_FLUIDS (SCM_I_CURRENT_THREAD->dynamic_state);
- SCM_SIMPLE_VECTOR_SET (fluids, n, value);
-}
-
static void
swap_fluids (SCM data)
{
SCM state;
SCM_NEWSMOB2 (state, tc16_dynamic_state,
SCM_UNPACK (fluids), SCM_UNPACK (SCM_EOL));
- all_dynamic_states = state;
return state;
}
SCM_NEWSMOB2 (state, tc16_dynamic_state,
SCM_UNPACK (fluids), SCM_UNPACK (SCM_EOL));
- /* The GC must not run until the state is properly entered into the
- list.
- */
- scm_i_scm_pthread_mutex_lock (&fluid_admin_mutex);
- SET_DYNAMIC_STATE_NEXT (state, all_dynamic_states);
- all_dynamic_states = state;
- scm_i_pthread_mutex_unlock (&fluid_admin_mutex);
-
return state;
}
#undef FUNC_NAME
scm_fluids_prehistory ()
{
tc16_fluid = scm_make_smob_type ("fluid", 0);
- scm_set_smob_free (tc16_fluid, fluid_free);
scm_set_smob_print (tc16_fluid, fluid_print);
tc16_dynamic_state = scm_make_smob_type ("dynamic-state", 0);
- scm_set_smob_mark (tc16_dynamic_state, scm_markcdr);
-
- scm_c_hook_add (&scm_after_sweep_c_hook, scan_dynamic_states_and_fluids,
- 0, 0);
}
void
HCoop / bpt / guile.git / blobdiff