From 6c036527a630720063b67d9a65455e8caca2c8fa Mon Sep 17 00:00:00 2001 From: Christoph Lameter Date: Thu, 7 Jul 2005 17:56:59 -0700 Subject: [PATCH] mostly_read data section Add a new section called ".data.read_mostly" for data items that are read frequently and rarely written to like cpumaps etc. If these maps are placed in the .data section then these frequenly read items may end up in cachelines with data is is frequently updated. In that case all processors in an SMP system must needlessly reload the cachelines again and again containing elements of those frequently used variables. The ability to share these cachelines will allow each cpu in an SMP system to keep local copies of those shared cachelines thereby optimizing performance. Signed-off-by: Alok N Kataria Signed-off-by: Shobhit Dayal Signed-off-by: Christoph Lameter Signed-off-by: Shai Fultheim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/i386/kernel/smpboot.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) (limited to 'arch/i386/kernel/smpboot.c') diff --git a/arch/i386/kernel/smpboot.c b/arch/i386/kernel/smpboot.c index d66bf48..8ac8e9f 100644 --- a/arch/i386/kernel/smpboot.c +++ b/arch/i386/kernel/smpboot.c @@ -68,21 +68,21 @@ EXPORT_SYMBOL(smp_num_siblings); #endif /* Package ID of each logical CPU */ -int phys_proc_id[NR_CPUS] = {[0 ... NR_CPUS-1] = BAD_APICID}; +int phys_proc_id[NR_CPUS] __read_mostly = {[0 ... NR_CPUS-1] = BAD_APICID}; EXPORT_SYMBOL(phys_proc_id); /* Core ID of each logical CPU */ -int cpu_core_id[NR_CPUS] = {[0 ... NR_CPUS-1] = BAD_APICID}; +int cpu_core_id[NR_CPUS] __read_mostly = {[0 ... NR_CPUS-1] = BAD_APICID}; EXPORT_SYMBOL(cpu_core_id); -cpumask_t cpu_sibling_map[NR_CPUS]; +cpumask_t cpu_sibling_map[NR_CPUS] __read_mostly; EXPORT_SYMBOL(cpu_sibling_map); -cpumask_t cpu_core_map[NR_CPUS]; +cpumask_t cpu_core_map[NR_CPUS] __read_mostly; EXPORT_SYMBOL(cpu_core_map); /* bitmap of online cpus */ -cpumask_t cpu_online_map; +cpumask_t cpu_online_map __read_mostly; EXPORT_SYMBOL(cpu_online_map); cpumask_t cpu_callin_map; @@ -100,7 +100,7 @@ static int __devinitdata tsc_sync_disabled; struct cpuinfo_x86 cpu_data[NR_CPUS] __cacheline_aligned; EXPORT_SYMBOL(cpu_data); -u8 x86_cpu_to_apicid[NR_CPUS] = +u8 x86_cpu_to_apicid[NR_CPUS] __read_mostly = { [0 ... NR_CPUS-1] = 0xff }; EXPORT_SYMBOL(x86_cpu_to_apicid); @@ -550,10 +550,10 @@ extern struct { #ifdef CONFIG_NUMA /* which logical CPUs are on which nodes */ -cpumask_t node_2_cpu_mask[MAX_NUMNODES] = +cpumask_t node_2_cpu_mask[MAX_NUMNODES] __read_mostly = { [0 ... MAX_NUMNODES-1] = CPU_MASK_NONE }; /* which node each logical CPU is on */ -int cpu_2_node[NR_CPUS] = { [0 ... NR_CPUS-1] = 0 }; +int cpu_2_node[NR_CPUS] __read_mostly = { [0 ... NR_CPUS-1] = 0 }; EXPORT_SYMBOL(cpu_2_node); /* set up a mapping between cpu and node. */ @@ -581,7 +581,7 @@ static inline void unmap_cpu_to_node(int cpu) #endif /* CONFIG_NUMA */ -u8 cpu_2_logical_apicid[NR_CPUS] = { [0 ... NR_CPUS-1] = BAD_APICID }; +u8 cpu_2_logical_apicid[NR_CPUS] __read_mostly = { [0 ... NR_CPUS-1] = BAD_APICID }; static void map_cpu_to_logical_apicid(void) { -- cgit v1.1