mm: replace various uses of num_physpages by totalram_pages

Sizing of memory allocations shouldn't depend on the number of physical
pages found in a system, as that generally includes (perhaps a huge amount
of) non-RAM pages.  The amount of what actually is usable as storage
should instead be used as a basis here.

Some of the calculations (i.e.  those not intending to use high memory)
should likely even use (totalram_pages - totalhigh_pages).

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: Dave Airlie <airlied@linux.ie>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Patrick McHardy <kaber@trash.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

net/core/sock.c

@@ -1206,12 +1206,12 @@ EXPORT_SYMBOL_GPL(sk_setup_caps);
 
 void __init sk_init(void)
 {
-	if (num_physpages <= 4096) {
+	if (totalram_pages <= 4096) {
 		sysctl_wmem_max = 32767;
 		sysctl_rmem_max = 32767;
 		sysctl_wmem_default = 32767;
 		sysctl_rmem_default = 32767;
-	} else if (num_physpages >= 131072) {
+	} else if (totalram_pages >= 131072) {
 		sysctl_wmem_max = 131071;
 		sysctl_rmem_max = 131071;
 	}