allow tasks to request dedicated stack space when created

Author: vtjnash

base/boot.jl

@@ -298,7 +298,7 @@ eval(:(Core.call(::Type{GlobalRef}, m::Module, s::Symbol) = $(Expr(:new, :Global
 
 Module(name::Symbol=:anonymous, std_imports::Bool=true) = ccall(:jl_f_new_module, Any, (Any, Bool), name, std_imports)::Module
 
-Task(f::ANY) = ccall(:jl_new_task, Any, (Any, Int), f::Function, 0)::Task
+Task(f::ANY, reserved_stack::Int=0) = ccall(:jl_new_task, Any, (Any, Int), f::Function, reserved_stack)::Task
 
 # simple convert for use by constructors of types in Core
 # note that there is no actual conversion defined here,

src/gc.c

@@ -1562,17 +1562,15 @@ static void gc_mark_task_stack(jl_task_t *ta, int d)
     if (ta == jl_current_task) {
         gc_mark_stack((jl_value_t*)ta, jl_pgcstack, 0, d);
     }
-    else if (ta == jl_root_task) {
+    else if (!ta->copy_stack) {
         gc_mark_stack((jl_value_t*)ta, ta->gcstack, 0, d);
     }
-    else if (ta->stkbuf != NULL && ta->stkbuf != (void*)(intptr_t)-1) {
 #ifdef COPY_STACKS
+    else if (ta->stkbuf != NULL && ta->stkbuf != (void*)(intptr_t)-1) {
         ptrint_t offset = (char *)ta->stkbuf + ta->ssize - (char *)jl_stackbase;
-#else
-        ptrint_t offset = 0;
-#endif
         gc_mark_stack((jl_value_t*)ta, ta->gcstack, offset, d);
     }
+#endif
 }
 
 NOINLINE static void gc_mark_task(jl_task_t *ta, int d)
@@ -1808,7 +1806,7 @@ double clock_now(void);
 
 extern jl_module_t *jl_old_base_module;
 extern jl_array_t *jl_module_init_order;
-extern jl_value_t *jl_unprotect_stack_func;
+extern jl_value_t *jl_task_cleanup_func;
 
 static int inc_count = 0;
 static int quick_count = 0;
@@ -1846,7 +1844,7 @@ static void pre_mark(void)
     }
 
     jl_mark_box_caches();
-    gc_push_root(jl_unprotect_stack_func, 0);
+    gc_push_root(jl_task_cleanup_func, 0);
     gc_push_root(jl_bottom_func, 0);
     gc_push_root(jl_typetype_type, 0);
 

src/julia.h

@@ -1389,7 +1389,8 @@ typedef struct _jl_task_t {
 #endif
     jl_jmp_buf ctx; // saved thread state
     void *stkbuf; // malloc'd memory
-    int ssize; // sizeof the portion of stack used in stkbuf
+    int ssize:31; // sizeof stkbuf
+    int copy_stack:1;
 
     // current exception handler
     jl_handler_t *eh;

src/signals-unix.c

@@ -14,17 +14,12 @@ void fpe_handler(int arg)
 
 static int is_addr_on_stack(void *addr)
 {
-#ifdef COPY_STACKS
-    if (jl_current_task == jl_root_task)
-        return ((char*)addr > (char*)jl_stack_lo-3000000 &&
-                (char*)addr < (char*)jl_stack_hi);
-    else
+    if (jl_current_task->copy_stack)
         return ((char*)addr > (char*)jl_stackbase - JL_STACK_SIZE &&
                 (char*)addr < (char*)jl_stackbase);
-#else
-    return ((char*)addr > (char*)jl_current_task->stkbuf &&
-            (char*)addr < (char*)jl_current_task->stkbuf + jl_current_task->ssize);
-#endif
+    else
+        return ((char*)addr > (char*)jl_current_task->stkbuf &&
+                (char*)addr < (char*)jl_current_task->stkbuf + jl_current_task->ssize);
 }
 
 #ifndef SIGINFO