[PATCH] alloc_tty_struct() wastage?

[Hugh Dickins]

I've been puzzling over alloc_tty_struct(), which seems determined
to waste memory on a machine of page size 8KB.  I've come to the
conclusion that it represents great caution on Russell's part
when introducing ARM, not to interfere with existing code of
other architectures - is that so, Russell?

But wouldn't we do better to use kmalloc() in all cases?  Unless
you know some reason why a tty_struct is better on its own page:
patch below against 2.4.2-ac9, applies with noise to 2.4.[012].

(I'm not about to follow this with a thousand patches,
replacing page allocation by kmalloc() in sundry places:
now's not the time, but this instance struck me as odd.)

Hugh

--- 2.4.2-ac9/drivers/char/tty_io.c	Fri Mar  2 18:22:36 2001
+++ linux/drivers/char/tty_io.c	Fri Mar  2 18:23:42 2001
@@ -173,22 +173,15 @@
 {
 	struct tty_struct *tty;
 
-	if (PAGE_SIZE > 8192) {
-		tty = kmalloc(sizeof(struct tty_struct), GFP_KERNEL);
-		if (tty)
-			memset(tty, 0, sizeof(struct tty_struct));
-	} else
-		tty = (struct tty_struct *)get_zeroed_page(GFP_KERNEL);
-
+	tty = kmalloc(sizeof(struct tty_struct), GFP_KERNEL);
+	if (tty)
+		memset(tty, 0, sizeof(struct tty_struct));
 	return tty;
 }
 
 static inline void free_tty_struct(struct tty_struct *tty)
 {
-	if (PAGE_SIZE > 8192)
-		kfree(tty);
-	else
-		free_page((unsigned long) tty);
+	kfree(tty);
 }
 
 /*
@@ -2239,9 +2232,6 @@
  */
 void __init tty_init(void)
 {
-	if (sizeof(struct tty_struct) > PAGE_SIZE)
-		panic("size of tty structure > PAGE_SIZE!");
-
 	/*
 	 * dev_tty_driver and dev_console_driver are actually magic
 	 * devices which get redirected at open time.  Nevertheless,