[PATCH] More __read_mostly variables

Move some more frequently read variables that showed up during some of our
performance tests as sometimes ending up in hot cachelines to the
read_mostly section.

Fix: Move the __read_mostly from before hpet_usec_quotient to follow the
variable like the other uses of __read_mostly.
Signed-off-by: NAlok N Kataria <alokk@calsoftinc.com>
Signed-off-by: NChristoph Lameter <christoph@scalex86.org>
Signed-off-by: NShai Fultheim <shai@scalex86.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

arch/i386/kernel/setup.c

@@ -82,7 +82,7 @@ EXPORT_SYMBOL(efi_enabled);
 /* cpu data as detected by the assembly code in head.S */
 struct cpuinfo_x86 new_cpu_data __initdata = { 0, 0, 0, 0, -1, 1, 0, 0, -1 };
 /* common cpu data for all cpus */
-struct cpuinfo_x86 boot_cpu_data = { 0, 0, 0, 0, -1, 1, 0, 0, -1 };
+struct cpuinfo_x86 boot_cpu_data __read_mostly = { 0, 0, 0, 0, -1, 1, 0, 0, -1 };
 EXPORT_SYMBOL(boot_cpu_data);
 
 unsigned long mmu_cr4_features;

arch/i386/kernel/timers/timer_hpet.c

@@ -18,7 +18,7 @@
 #include "mach_timer.h"
 #include <asm/hpet.h>
 
-static unsigned long __read_mostly hpet_usec_quotient;	/* convert hpet clks to usec */
+static unsigned long hpet_usec_quotient __read_mostly;	/* convert hpet clks to usec */
 static unsigned long tsc_hpet_quotient;		/* convert tsc to hpet clks */
 static unsigned long hpet_last; 	/* hpet counter value at last tick*/
 static unsigned long last_tsc_low;	/* lsb 32 bits of Time Stamp Counter */

mm/mmap.c

@@ -61,7 +61,7 @@ pgprot_t protection_map[16] = {
 
 int sysctl_overcommit_memory = OVERCOMMIT_GUESS;  /* heuristic overcommit */
 int sysctl_overcommit_ratio = 50;	/* default is 50% */
-int sysctl_max_map_count = DEFAULT_MAX_MAP_COUNT;
+int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT;
 atomic_t vm_committed_space = ATOMIC_INIT(0);
 
 /*

mm/page_alloc.c

@@ -42,11 +42,11 @@
  * MCD - HACK: Find somewhere to initialize this EARLY, or make this
  * initializer cleaner
  */
-nodemask_t node_online_map = { { [0] = 1UL } };
+nodemask_t node_online_map __read_mostly = { { [0] = 1UL } };
 EXPORT_SYMBOL(node_online_map);
-nodemask_t node_possible_map = NODE_MASK_ALL;
+nodemask_t node_possible_map __read_mostly = NODE_MASK_ALL;
 EXPORT_SYMBOL(node_possible_map);
-struct pglist_data *pgdat_list;
+struct pglist_data *pgdat_list __read_mostly;
 unsigned long totalram_pages;
 unsigned long totalhigh_pages;
 long nr_swap_pages;
@@ -68,7 +68,7 @@ EXPORT_SYMBOL(nr_swap_pages);
  * Used by page_zone() to look up the address of the struct zone whose
  * id is encoded in the upper bits of page->flags
  */
-struct zone *zone_table[1 << ZONETABLE_SHIFT];
+struct zone *zone_table[1 << ZONETABLE_SHIFT] __read_mostly;
 EXPORT_SYMBOL(zone_table);
 
 static char *zone_names[MAX_NR_ZONES] = { "DMA", "Normal", "HighMem" };