[PATCH] Additions to .data.read_mostly section

Mark variables which are usually accessed for reads with __readmostly.

Signed-off-by: Alok N Kataria <[e-mail]>
Signed-off-by: Shai Fultheim <[e-mail]>
Signed-off-by: Ravikiran Thirumalai <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

arch/i386/kernel/io_apic.c

···
 	int apic, pin, next;
 } irq_2_pin[PIN_MAP_SIZE];
 
-int vector_irq[NR_VECTORS] = { [0 ... NR_VECTORS - 1] = -1};
+int vector_irq[NR_VECTORS] __read_mostly = { [0 ... NR_VECTORS - 1] = -1};
 #ifdef CONFIG_PCI_MSI
 #define vector_to_irq(vector) 	\
 	(platform_legacy_irq(vector) ? vector : vector_irq[vector])
···
 }
 
 /* irq_vectors is indexed by the sum of all RTEs in all I/O APICs. */
-u8 irq_vector[NR_IRQ_VECTORS] = { FIRST_DEVICE_VECTOR , 0 };
+u8 irq_vector[NR_IRQ_VECTORS] __read_mostly = { FIRST_DEVICE_VECTOR , 0 };
 
 int assign_irq_vector(int irq)
 {
···
  * edge-triggered handler, without risking IRQ storms and other ugly
  * races.
  */
-static struct hw_interrupt_type ioapic_edge_type = {
+static struct hw_interrupt_type ioapic_edge_type __read_mostly = {
 	.typename 	= "IO-APIC-edge",
 	.startup 	= startup_edge_ioapic,
 	.shutdown 	= shutdown_edge_ioapic,
···
 #endif
 };
 
-static struct hw_interrupt_type ioapic_level_type = {
+static struct hw_interrupt_type ioapic_level_type __read_mostly = {
 	.typename 	= "IO-APIC-level",
 	.startup 	= startup_level_ioapic,
 	.shutdown 	= shutdown_level_ioapic,
···
 
 static void end_lapic_irq (unsigned int i) { /* nothing */ }
 
-static struct hw_interrupt_type lapic_irq_type = {
+static struct hw_interrupt_type lapic_irq_type __read_mostly = {
 	.typename 	= "local-APIC-edge",
 	.startup 	= NULL, /* startup_irq() not used for IRQ0 */
 	.shutdown 	= NULL, /* shutdown_irq() not used for IRQ0 */

arch/i386/kernel/timers/timer_hpet.c

···
 #include <asm/hpet.h>
 
 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 tsc_hpet_quotient __read_mostly;	/* 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 */
 static unsigned long last_tsc_high; 	/* msb 32 bits of Time Stamp Counter */

arch/i386/mm/discontig.c

···
 #include <asm/mmzone.h>
 #include <bios_ebda.h>
 
-struct pglist_data *node_data[MAX_NUMNODES];
+struct pglist_data *node_data[MAX_NUMNODES] __read_mostly;
 EXPORT_SYMBOL(node_data);
 bootmem_data_t node0_bdata;
 
···
  * 2) node_start_pfn   - the starting page frame number for a node
  * 3) node_end_pfn     - the ending page fram number for a node
  */
-unsigned long node_start_pfn[MAX_NUMNODES];
-unsigned long node_end_pfn[MAX_NUMNODES];
+unsigned long node_start_pfn[MAX_NUMNODES] __read_mostly;
+unsigned long node_end_pfn[MAX_NUMNODES] __read_mostly;
 
 
 #ifdef CONFIG_DISCONTIGMEM
···
  *     physnode_map[4-7] = 1;
  *     physnode_map[8- ] = -1;
  */
-s8 physnode_map[MAX_ELEMENTS] = { [0 ... (MAX_ELEMENTS - 1)] = -1};
+s8 physnode_map[MAX_ELEMENTS] __read_mostly = { [0 ... (MAX_ELEMENTS - 1)] = -1};
 EXPORT_SYMBOL(physnode_map);
 
 void memory_present(int nid, unsigned long start, unsigned long end)

arch/i386/mm/init.c

···
 }
 
 static int disable_nx __initdata = 0;
-u64 __supported_pte_mask = ~_PAGE_NX;
+u64 __supported_pte_mask __read_mostly = ~_PAGE_NX;
 
 /*
  * noexec = on|off

arch/x86_64/kernel/genapic.c

···
 #endif
 
 /* which logical CPU number maps to which CPU (physical APIC ID) */
-u8 x86_cpu_to_apicid[NR_CPUS] = { [0 ... NR_CPUS-1] = BAD_APICID };
+u8 x86_cpu_to_apicid[NR_CPUS] __read_mostly = { [0 ... NR_CPUS-1] = BAD_APICID };
 EXPORT_SYMBOL(x86_cpu_to_apicid);
 u8 x86_cpu_to_log_apicid[NR_CPUS] = { [0 ... NR_CPUS-1] = BAD_APICID };
 

arch/x86_64/kernel/io_apic.c

···
 	short apic, pin, next;
 } irq_2_pin[PIN_MAP_SIZE];
 
-int vector_irq[NR_VECTORS] = { [0 ... NR_VECTORS - 1] = -1};
+int vector_irq[NR_VECTORS] __read_mostly = { [0 ... NR_VECTORS - 1] = -1};
 #ifdef CONFIG_PCI_MSI
 #define vector_to_irq(vector) 	\
 	(platform_legacy_irq(vector) ? vector : vector_irq[vector])
···
 }
 
 /* irq_vectors is indexed by the sum of all RTEs in all I/O APICs. */
-u8 irq_vector[NR_IRQ_VECTORS] = { FIRST_DEVICE_VECTOR , 0 };
+u8 irq_vector[NR_IRQ_VECTORS] __read_mostly = { FIRST_DEVICE_VECTOR , 0 };
 
 int assign_irq_vector(int irq)
 {
···
  * races.
  */
 
-static struct hw_interrupt_type ioapic_edge_type = {
+static struct hw_interrupt_type ioapic_edge_type __read_mostly = {
 	.typename = "IO-APIC-edge",
 	.startup 	= startup_edge_ioapic,
 	.shutdown 	= shutdown_edge_ioapic,
···
 #endif
 };
 
-static struct hw_interrupt_type ioapic_level_type = {
+static struct hw_interrupt_type ioapic_level_type __read_mostly = {
 	.typename = "IO-APIC-level",
 	.startup 	= startup_level_ioapic,
 	.shutdown 	= shutdown_level_ioapic,
···
 
 static void end_lapic_irq (unsigned int i) { /* nothing */ }
 
-static struct hw_interrupt_type lapic_irq_type = {
+static struct hw_interrupt_type lapic_irq_type __read_mostly = {
 	.typename = "local-APIC-edge",
 	.startup = NULL, /* startup_irq() not used for IRQ0 */
 	.shutdown = NULL, /* shutdown_irq() not used for IRQ0 */

arch/x86_64/kernel/setup.c

···
  * Machine setup..
  */
 
-struct cpuinfo_x86 boot_cpu_data;
+struct cpuinfo_x86 boot_cpu_data __read_mostly;
 
 unsigned long mmu_cr4_features;
 

arch/x86_64/kernel/setup64.c

···
 
 char boot_cpu_stack[IRQSTACKSIZE] __attribute__((section(".bss.page_aligned")));
 
-unsigned long __supported_pte_mask = ~0UL;
+unsigned long __supported_pte_mask __read_mostly = ~0UL;
 static int do_not_nx __initdata = 0;
 
 /* noexec=on|off

arch/x86_64/kernel/smpboot.c

···
 /* Number of siblings per CPU package */
 int smp_num_siblings = 1;
 /* Package ID of each logical CPU */
-u8 phys_proc_id[NR_CPUS] = { [0 ... NR_CPUS-1] = BAD_APICID };
-u8 cpu_core_id[NR_CPUS] = { [0 ... NR_CPUS-1] = BAD_APICID };
+u8 phys_proc_id[NR_CPUS] __read_mostly = { [0 ... NR_CPUS-1] = BAD_APICID };
+u8 cpu_core_id[NR_CPUS] __read_mostly = { [0 ... NR_CPUS-1] = BAD_APICID };
 EXPORT_SYMBOL(phys_proc_id);
 EXPORT_SYMBOL(cpu_core_id);
 
 /* Bitmask of currently online CPUs */
-cpumask_t cpu_online_map;
+cpumask_t cpu_online_map __read_mostly;
 
 EXPORT_SYMBOL(cpu_online_map);
 
···
 /* Set when the idlers are all forked */
 int smp_threads_ready;
 
-cpumask_t cpu_sibling_map[NR_CPUS] __cacheline_aligned;
-cpumask_t cpu_core_map[NR_CPUS] __cacheline_aligned;
+cpumask_t cpu_sibling_map[NR_CPUS] __read_mostly;
+cpumask_t cpu_core_map[NR_CPUS] __read_mostly;
 EXPORT_SYMBOL(cpu_core_map);
 
 /*

arch/x86_64/mm/numa.c

···
 #define Dprintk(x...)
 #endif
 
-struct pglist_data *node_data[MAX_NUMNODES];
+struct pglist_data *node_data[MAX_NUMNODES] __read_mostly;
 bootmem_data_t plat_node_bdata[MAX_NUMNODES];
 
 int memnode_shift;
 u8  memnodemap[NODEMAPSIZE];
 
-unsigned char cpu_to_node[NR_CPUS] = { [0 ... NR_CPUS-1] = NUMA_NO_NODE };
-cpumask_t     node_to_cpumask[MAX_NUMNODES];
+unsigned char cpu_to_node[NR_CPUS] __read_mostly = { [0 ... NR_CPUS-1] = NUMA_NO_NODE };
+cpumask_t     node_to_cpumask[MAX_NUMNODES] __read_mostly;
 
 int numa_off __initdata;
 

fs/namespace.c

···
  __cacheline_aligned_in_smp DEFINE_SPINLOCK(vfsmount_lock);
 
 static struct list_head *mount_hashtable;
-static int hash_mask, hash_bits;
+static int hash_mask __read_mostly, hash_bits __read_mostly;
 static kmem_cache_t *mnt_cache; 
 
 static inline unsigned long hash(struct vfsmount *mnt, struct dentry *dentry)

mm/page_alloc.c

···
 nodemask_t node_possible_map __read_mostly = NODE_MASK_ALL;
 EXPORT_SYMBOL(node_possible_map);
 struct pglist_data *pgdat_list __read_mostly;
-unsigned long totalram_pages;
-unsigned long totalhigh_pages;
+unsigned long totalram_pages __read_mostly;
+unsigned long totalhigh_pages __read_mostly;
 long nr_swap_pages;
 
 /*

mm/shmem.c

···
 static struct inode_operations shmem_dir_inode_operations;
 static struct vm_operations_struct shmem_vm_ops;
 
-static struct backing_dev_info shmem_backing_dev_info = {
+static struct backing_dev_info shmem_backing_dev_info  __read_mostly = {
 	.ra_pages	= 0,	/* No readahead */
 	.capabilities	= BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
 	.unplug_io_fn	= default_unplug_io_fn,