ulimit: change from RSS to virtual size

For some reason the max-RSS limit doesn't seem to be kicking in.
Switch to putting a limit on the virtual size instead, and bump the
limit from 500MB to 1.5GB.

Makefile

@@ -31,8 +31,8 @@ GTEST_DIR := $(DEPS_DIR)/gtest-1.7.0
 
 USE_DEBUG_LIBUNWIND := 0
 
-MAX_MEM_KB := 500000
-MAX_DBG_MEM_KB := 500000
+MAX_MEM_KB := 1500000
+MAX_DBG_MEM_KB := 1500000
 
 TEST_THREADS := 1
 
@@ -411,10 +411,10 @@ $1_unittest:
 	$(NINJA) -C $(CMAKE_DIR_DBG) $1_unittest $(NINJAFLAGS)
 	ln -sf $(CMAKE_DIR_DBG)/$1_unittest .
 dbg_$1_unittests: $1_unittest
-	zsh -c 'ulimit -m $(MAX_MEM_KB); time $(GDB) $(GDB_CMDS) --args ./$1_unittest --gtest_break_on_failure $(ARGS)'
+	zsh -c 'ulimit -v $(MAX_MEM_KB); time $(GDB) $(GDB_CMDS) --args ./$1_unittest --gtest_break_on_failure $(ARGS)'
 unittests:: $1_unittest
 run_$1_unittests: $1_unittest
-	zsh -c 'ulimit -m $(MAX_MEM_KB); time ./$1_unittest $(ARGS)'
+	zsh -c 'ulimit -v $(MAX_MEM_KB); time ./$1_unittest $(ARGS)'
 run_unittests:: run_$1_unittests
 )
 endef
@@ -770,12 +770,12 @@ check$1 test$1: $(PYTHON_EXE_DEPS) pyston$1
 run$1: pyston$1 $$(RUN_DEPS)
 	PYTHONPATH=test/test_extension:$${PYTHONPATH} ./pyston$1 $$(ARGS)
 dbg$1: pyston$1 $$(RUN_DEPS)
-	PYTHONPATH=test/test_extension:$${PYTHONPATH} zsh -c 'ulimit -m $$(MAX_DBG_MEM_KB); $$(GDB) $$(GDB_CMDS) --args ./pyston$1 $$(ARGS)'
+	PYTHONPATH=test/test_extension:$${PYTHONPATH} zsh -c 'ulimit -v $$(MAX_DBG_MEM_KB); $$(GDB) $$(GDB_CMDS) --args ./pyston$1 $$(ARGS)'
 nosearch_run$1_%: %.py pyston$1 $$(RUN_DEPS)
-	$(VERB) PYTHONPATH=test/test_extension:$${PYTHONPATH} zsh -c 'ulimit -m $$(MAX_MEM_KB); time ./pyston$1 $$(ARGS) $$<'
+	$(VERB) PYTHONPATH=test/test_extension:$${PYTHONPATH} zsh -c 'ulimit -v $$(MAX_MEM_KB); time ./pyston$1 $$(ARGS) $$<'
 $$(call make_search,run$1_%)
 nosearch_dbg$1_%: %.py pyston$1 $$(RUN_DEPS)
-	$(VERB) PYTHONPATH=test/test_extension:$${PYTHONPATH} zsh -c 'ulimit -m $$(MAX_DBG_MEM_KB); $$(GDB) $$(GDB_CMDS) --args ./pyston$1 $$(ARGS) $$<'
+	$(VERB) PYTHONPATH=test/test_extension:$${PYTHONPATH} zsh -c 'ulimit -v $$(MAX_DBG_MEM_KB); $$(GDB) $$(GDB_CMDS) --args ./pyston$1 $$(ARGS) $$<'
 $$(call make_search,dbg$1_%)
 
 ifneq ($$(ENABLE_VALGRIND),0)
@@ -905,7 +905,7 @@ opreportcg:
 
 .PHONY: watch_% watch wdbg_%
 watch_%:
-	@ ( ulimit -t 60; ulimit -m $(MAK_MEM_KB); \
+	@ ( ulimit -t 60; ulimit -v $(MAK_MEM_KB); \
 		TARGET=$(dir $@)$(patsubst watch_%,%,$(notdir $@)); \
 		clear; $(MAKE) $$TARGET $(WATCH_ARGS); true; \
 		while inotifywait -q -e modify -e attrib -e move -e move_self -e create -e delete -e delete_self \
@@ -953,7 +953,7 @@ test_cpp_ll:
 .PHONY: bench_exceptions
 bench_exceptions:
 	$(CLANGPP_EXE) $(TEST_DIR)/bench_exceptions.cpp -o bench_exceptions -O3 -std=c++11
-	zsh -c 'ulimit -m $(MAX_MEM_KB); time ./bench_exceptions'
+	zsh -c 'ulimit -v $(MAX_MEM_KB); time ./bench_exceptions'
 	rm bench_exceptions
 
 TEST_EXT_MODULE_NAMES := basic_test descr_test slots_test type_test api_test