Refactor startup optimizations

+ Add doom-gc-cons-upper-limit variable
+ Don't use most-positive-fixnum, in case Emacs somehow wants to
  allocate that much!
+ Don't use startup optimizations in noninteractive sessions
+ Restore gc-cons-threshold on idle timer, instead of hook (to defer the
  possible GC pause and so deferred packages can take advantage of these
  optimizations).

core/core.el

@@ -300,7 +300,7 @@ original value of `symbol-file'."
 
 ;; Don't garbage collect to speed up minibuffer commands
 (defun doom|defer-garbage-collection ()
-  (setq gc-cons-threshold most-positive-fixnum))
+  (setq gc-cons-threshold doom-gc-cons-upper-limit))
 (defun doom|restore-garbage-collection ()
   (setq gc-cons-threshold doom-gc-cons-threshold))
 (add-hook 'minibuffer-setup-hook #'doom|defer-garbage-collection)
@@ -318,12 +318,13 @@ easier to tell where the came from.
 Meant to be used with `run-hook-wrapped'."
   (when doom-debug-mode
     (message "Running doom hook: %s" hook))
-  (condition-case e
-      (funcall hook)
-    ((debug error)
-     (signal 'doom-hook-error (list hook e))))
-  ;; return nil so `run-hook-wrapped' won't short circuit
-  nil)
+  (let ((gc-cons-threshold doom-gc-cons-upper-limit))
+    (condition-case e
+        (funcall hook)
+      ((debug error)
+       (signal 'doom-hook-error (list hook e))))
+    ;; return nil so `run-hook-wrapped' won't short circuit
+    nil))
 
 (defun doom-ensure-same-emacs-version-p ()
   "Check if the running version of Emacs has changed and set

init.el

@@ -27,30 +27,38 @@
 ;;
 ;;; License: MIT
 
-(defvar doom-gc-cons-threshold (* 8 1024 1024)
-  "The default value to use for `gc-cons-threshold'.")
+(defvar doom-gc-cons-threshold 16777216 ; 16mb
+  "The default value to use for `gc-cons-threshold'. If you experience freezing,
+decrease this. If you experience stuttering, increase this.")
+
+(defvar doom-gc-cons-upper-limit 268435456 ; 256mb
+  "The temporary value for `gc-cons-threshold' to defer it.")
 
 
 (defvar doom--file-name-handler-alist file-name-handler-alist)
-(unless after-init-time
+
+(defun doom|restore-startup-optimizations ()
+  "Resets garbage collection settings to reasonable defaults (a large
+`gc-cons-threshold' can cause random freezes otherwise) and resets
+`file-name-handler-alist'."
+  (setq file-name-handler-alist doom--file-name-handler-alist
+        gc-cons-threshold doom-gc-cons-threshold))
+
+
+(if (or after-init-time noninteractive)
+    (setq gc-cons-threshold doom-gc-cons-threshold)
   ;; A big contributor to long startup times is the garbage collector, so we up
   ;; its memory threshold, temporarily and reset it later in
   ;; `doom|disable-startup-optimizations'.
-  (setq gc-cons-threshold most-positive-fixnum)
+  (setq gc-cons-threshold doom-gc-cons-upper-limit) ; 256mb
   ;; This is consulted on every `require', `load' and various file reading
   ;; functions. You get a minor speed up by nooping this.
-  (setq file-name-handler-alist nil))
-
-(defun doom|disable-startup-optimizations ()
-  "Resets garbage collection settings to reasonable defaults (if you don't do
-this, you'll get stuttering and random freezes) and resets
-`file-name-handler-alist'."
-  (setq file-name-handler-alist doom--file-name-handler-alist
-        gc-cons-threshold doom-gc-cons-threshold)
-  (makunbound 'doom--file-name-handler-alist))
-
-(add-hook 'emacs-startup-hook #'doom|disable-startup-optimizations)
-(add-hook 'doom-reload-hook   #'doom|disable-startup-optimizations)
+  (setq file-name-handler-alist nil)
+  ;; Restore these to their defaults later. Do it on an idle timer to defer the
+  ;; possible GC pause, and to give deferred packages the ability to take
+  ;; advantage of these optimizations.
+  (run-with-idle-timer 5 nil #'doom|restore-startup-optimizations)
+  (add-hook 'doom-reload-hook #'doom|restore-startup-optimizations))
 
 
 ;; Ensure Doom is always running out of this file's directory
@@ -60,5 +68,6 @@ this, you'll get stuttering and random freezes) and resets
 ;; load errors, it may help to set this to nil.
 (setq load-prefer-newer noninteractive)
 
+
 ;; Let 'er rip!
 (require 'core (concat user-emacs-directory "core/core"))