chore: remove extra consistency check

runtime/include/arch/common.h

@@ -68,5 +68,3 @@ extern __thread struct arch_context worker_thread_base_context;
 
 /* Cannot be inlined because called in assembly */
 void __attribute__((noinline)) __attribute__((noreturn)) arch_context_restore_preempted(void);
-
-extern __thread volatile bool worker_thread_is_switching_context;

runtime/include/arch/x86_64/context.h

@@ -175,6 +175,5 @@ arch_context_switch(struct arch_context *a, struct arch_context *b)
 	    "xmm3", "xmm4", "xmm5", "xmm6", "xmm7", "xmm8", "xmm9", "xmm10", "xmm11", "xmm12", "xmm13", "xmm14",
 	    "xmm15");
 
-	worker_thread_is_switching_context = false;
 	return 0;
 }

runtime/include/sandbox.h

@@ -80,9 +80,6 @@ struct sandbox {
  * Externs                 *
  **************************/
 
-
-extern __thread volatile bool worker_thread_is_switching_context;
-
 extern void worker_thread_block_current_sandbox(void);
 extern void worker_thread_on_sandbox_exit(struct sandbox *sandbox);
 extern void worker_thread_process_io(void);

runtime/src/local_runqueue_minheap.c

@@ -160,8 +160,6 @@ local_runqueue_minheap_preempt(ucontext_t *user_context)
 		next_sandbox->state = SANDBOX_RUNNABLE;
 		local_runqueue_add(next_sandbox);
 
-		worker_thread_is_switching_context = true;
-
 		/* Save the context of the currently executing sandbox before switching from it */
 		arch_mcontext_save(&current_sandbox->ctxt, &user_context->uc_mcontext);
 

runtime/src/sandbox.c

@@ -251,7 +251,6 @@ current_sandbox_main(void)
 
 	assert(!software_interrupt_is_enabled());
 	arch_context_init(&sandbox->ctxt, 0, 0);
-	worker_thread_is_switching_context = false;
 	software_interrupt_enable();
 
 	sandbox_initialize_io_handles_and_file_descriptors(sandbox);

runtime/src/software_interrupt.c

@@ -86,9 +86,6 @@ software_interrupt_handle_signals(int signal_type, siginfo_t *signal_info, void
 		/* NOOP if software interrupts not enabled */
 		if (!software_interrupt_is_enabled()) return;
 
-		/* Do not allow more than one layer of preemption */
-		if (worker_thread_is_switching_context) return;
-
 		/*
 		 * if a SIGALRM fires while the worker thread is between sandboxes, executing libuv, completion queue
 		 * cleanup, etc. current_sandbox might be NULL. In this case, we should just allow return to allow the
@@ -131,7 +128,6 @@ software_interrupt_handle_signals(int signal_type, siginfo_t *signal_info, void
 
 		arch_mcontext_restore(&user_context->uc_mcontext, &current_sandbox->ctxt);
 
-		worker_thread_is_switching_context = false;
 		software_interrupt_enable();
 
 		return;

runtime/src/worker_thread.c

@@ -29,9 +29,6 @@ __thread uv_loop_t worker_thread_uvio_handle;
 /* Flag to signify if the thread is currently running callbacks in the libuv event loop */
 static __thread bool worker_thread_is_in_libuv_event_loop = false;
 
-/* Flag to signify if the thread is currently undergoing a context switch */
-__thread volatile bool worker_thread_is_switching_context = false;
-
 /***********************
  * Worker Thread Logic *
  **********************/
@@ -51,8 +48,6 @@ worker_thread_switch_to_sandbox(struct sandbox *next_sandbox)
 	assert(next_sandbox != NULL);
 	struct arch_context *next_context = &next_sandbox->ctxt;
 
-	worker_thread_is_switching_context = true;
-
 	/* Get the old sandbox we're switching from */
 	struct sandbox *current_sandbox = current_sandbox_get();
 
@@ -92,8 +87,6 @@ static inline void
 worker_thread_switch_to_base_context()
 {
 	assert(!software_interrupt_is_enabled());
-	assert(worker_thread_is_switching_context == false);
-	worker_thread_is_switching_context = true;
 
 	struct sandbox *current_sandbox = current_sandbox_get();
 
@@ -110,7 +103,6 @@ worker_thread_switch_to_base_context()
 	arch_context_switch(&current_sandbox->ctxt, &worker_thread_base_context);
 
 	software_interrupt_enable();
-	worker_thread_is_switching_context = false;
 }
 
 /**
@@ -222,7 +214,6 @@ worker_thread_main(void *return_code)
 	/* Initialize Flags */
 	software_interrupt_is_disabled       = false;
 	worker_thread_is_in_libuv_event_loop = false;
-	worker_thread_is_switching_context   = false;
 
 	/* Unmask signals */
 #ifndef PREEMPT_DISABLE