(scm_block_gc, scm_gc_heap_lock): Removed. Removed all uses.
(scm_gc_running_p): Now a macro that refers to the scm_i_thread
field.
(scm_i_sweep_mutex): Now a non-recursive mutex. GC can not happen
recursively.
(scm_igc, scm_i_gc): Renamed former to latter. Changed all uses.
Do not lock scm_i_sweep_mutex, which is now non-recursive, or set
scm_gc_running_p. Do not run the scm_after_gc_c_hook.
(scm_gc): Lock scm_i_sweep_mutex, set scm_gc_running_p and run the
scm_after_gc_c_hook here.
(scm_gc_for_new_cell): Set scm_gc_running_p here and run the
scm_after_gc_c_hook when a full GC has in fact been performed.
(scm_i_expensive_validation_check): Call scm_gc, not scm_i_gc.
* gc-segment.c (scm_i_get_new_heap_segment): Do not check
scm_gc_heap_lock.
* gc-malloc.c (scm_realloc, increase_mtrigger): Set
scm_gc_running_p while the scm_i_sweep_mutex is locked.
Collapsed ensure_state_size and ensure_all_state_sizes into one
function named resize_all_states. Allocate new vectors outside of
single threaded region. Do only simple things inside that region.
(scm_make_fluid, scm_make_dynamic_state): Lock fluid_admin_mutex while
adding to the global lists.
(scm_i_thread): Removed unused signal_asyncs field.
(threads_mark): Do not mark it.
(guilify_self_1): Do not initialize it. Do initialize
continuation_root field.
(do_thread_exit): Do not remove thread from all_threads list.
(on_thread_exit): Do it here, after leaving guile mode.
(sleep_level): Removed.
(scm_i_thread_put_to_sleep): Leave thread_admin_mutex locked when
returning. Do not support recursive sleeps.
(scm_i_thread_wake_up): Expect thread_admin_mutex to be locked on
entry. Do not support recursive sleeps.
SCM_CRITICAL_SECTION_END): Moved here from threads.h since now
they also block/unblock execution of asyncs and call
scm_async_click which is declared in async.h but threads.h can not
include async.h since async.h already includes threads.h.
(scm_i_critical_section_level): New, for checking mistakes in the
use of the SCM_CRITICAL_SECTION_* macros.
(scm_i_critical_section_mutex): Make it a recursive mutex so that
critical sections can be nested.
* threads.h, threads.c (scm_frame_lock_mutex): New.
(scm_frame_critical_section): Take mutex as argument.
(framed_critical_section_mutex): New, used as default for above.
(scm_init_threads): Initialize it.
(scm_threads_prehistory): Do not initialize thread_admin_mutex and
scm_i_critical_section_mutex; both are initialized statically.
(scm_program_arguments, scm_set_program_arguments): Use it instead
of scm_progargs.
(scm_init_feature): Allocate it. Also, only add "threads" feature
when SCM_USE_PTHREAD_THREADS is true.
so that no two weak alist vectors share a spine.
(scm_hash_fn_create_handle_x): Deal with a possible rehashing
during GC before inserting the new alist cell.
