Commit 3461b0af authored by Mike Travis's avatar Mike Travis Committed by Ingo Molnar
Browse files

x86: remove static boot_cpu_pda array v2 

  * Remove the boot_cpu_pda array and pointer table from the data section.
    Allocate the pointer table and array during init.  do_boot_cpu()
    will reallocate the pda in node local memory and if the cpu is being
    brought up before the bootmem array is released (after_bootmem = 0),
    then it will free the initial pda.  This will happen for all cpus
    present at system startup.

    This removes 512k + 32k bytes from the data section.

For inclusion into sched-devel/latest tree.

Based on:
	git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git


    +   sched-devel/latest  .../mingo/linux-2.6-sched-devel.git

Signed-off-by: default avatarMike Travis <travis@sgi.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 9f248bde

arch/x86/kernel/head64.c

+23 −3
Original line number Diff line number Diff line
@@ -25,6 +25,24 @@ 
#include <asm/e820.h>

#include <asm/bios_ebda.h>



/* boot cpu pda */

static struct x8664_pda _boot_cpu_pda __read_mostly;



#ifdef CONFIG_SMP

#ifdef CONFIG_DEBUG_PER_CPU_MAPS

/*

 * We install an empty cpu_pda pointer table to trap references before

 * the actual cpu_pda pointer table is created in setup_cpu_pda_map().

 */

static struct x8664_pda *__cpu_pda[NR_CPUS] __initdata;

#else

static struct x8664_pda *__cpu_pda[1] __read_mostly;

#endif



#else /* !CONFIG_SMP (NR_CPUS will be 1) */

static struct x8664_pda *__cpu_pda[NR_CPUS] __read_mostly;

#endif



static void __init zap_identity_mappings(void)

{

	pgd_t *pgd = pgd_offset_k(0UL);
@@ -156,10 +174,12 @@ void __init x86_64_start_kernel(char * real_mode_data) 


	early_printk("Kernel alive\n");



 	for (i = 0; i < NR_CPUS; i++)

 		cpu_pda(i) = &boot_cpu_pda[i];



	_cpu_pda = __cpu_pda;

	cpu_pda(0) = &_boot_cpu_pda;

	pda_init(0);



	early_printk("Kernel really alive\n");



	copy_bootdata(__va(real_mode_data));



	reserve_early(__pa_symbol(&_text), __pa_symbol(&_end), "TEXT DATA BSS");

arch/x86/kernel/setup.c

+57 −16
Original line number Diff line number Diff line
@@ -101,6 +101,50 @@ static inline void setup_cpumask_of_cpu(void) { } 
 */

unsigned long __per_cpu_offset[NR_CPUS] __read_mostly;

EXPORT_SYMBOL(__per_cpu_offset);

static inline void setup_cpu_pda_map(void) { }



#elif !defined(CONFIG_SMP)

static inline void setup_cpu_pda_map(void) { }



#else /* CONFIG_SMP && CONFIG_X86_64 */



/*

 * Allocate cpu_pda pointer table and array via alloc_bootmem.

 */

static void __init setup_cpu_pda_map(void)

{

	char *pda;

	struct x8664_pda **new_cpu_pda;

	unsigned long size;

	int cpu;



	size = roundup(sizeof(struct x8664_pda), cache_line_size());



	/* allocate cpu_pda array and pointer table */

	{

		unsigned long tsize = nr_cpu_ids * sizeof(void *);

		unsigned long asize = size * (nr_cpu_ids - 1);



		tsize = roundup(tsize, cache_line_size());

		new_cpu_pda = alloc_bootmem(tsize + asize);

		pda = (char *)new_cpu_pda + tsize;

	}



	/* initialize pointer table to static pda's */

	for_each_possible_cpu(cpu) {

		if (cpu == 0) {

			/* leave boot cpu pda in place */

			new_cpu_pda[0] = cpu_pda(0);

			continue;

		}

		new_cpu_pda[cpu] = (struct x8664_pda *)pda;

		new_cpu_pda[cpu]->in_bootmem = 1;

		pda += size;

	}



	/* point to new pointer table */

	_cpu_pda = new_cpu_pda;

}

#endif



/*
@@ -110,46 +154,43 @@ EXPORT_SYMBOL(__per_cpu_offset); 
 */

void __init setup_per_cpu_areas(void)

{

	int i, highest_cpu = 0;

	unsigned long size;

	ssize_t size = PERCPU_ENOUGH_ROOM;

	char *ptr;

	int cpu;



#ifdef CONFIG_HOTPLUG_CPU

	prefill_possible_map();

#else

	nr_cpu_ids = num_processors;

#endif



	/* Setup cpu_pda map */

	setup_cpu_pda_map();



	/* Copy section for each CPU (we discard the original) */

	size = PERCPU_ENOUGH_ROOM;

	printk(KERN_INFO "PERCPU: Allocating %lu bytes of per cpu data\n",

			  size);



	for_each_possible_cpu(i) {

		char *ptr;

	for_each_possible_cpu(cpu) {

#ifndef CONFIG_NEED_MULTIPLE_NODES

		ptr = alloc_bootmem_pages(size);

#else

		int node = early_cpu_to_node(i);

		int node = early_cpu_to_node(cpu);

		if (!node_online(node) || !NODE_DATA(node)) {

			ptr = alloc_bootmem_pages(size);

			printk(KERN_INFO

			       "cpu %d has no node %d or node-local memory\n",

				i, node);

				cpu, node);

		}

		else

			ptr = alloc_bootmem_pages_node(NODE_DATA(node), size);

#endif

		if (!ptr)

			panic("Cannot allocate cpu data for CPU %d\n", i);

#ifdef CONFIG_X86_64

		cpu_pda(i)->data_offset = ptr - __per_cpu_start;

#else

		__per_cpu_offset[i] = ptr - __per_cpu_start;

#endif

		per_cpu_offset(cpu) = ptr - __per_cpu_start;

		memcpy(ptr, __per_cpu_start, __per_cpu_end - __per_cpu_start);



		highest_cpu = i;

	}



	nr_cpu_ids = highest_cpu + 1;

	printk(KERN_DEBUG "NR_CPUS: %d, nr_cpu_ids: %d, nr_node_ids %d\n",

		NR_CPUS, nr_cpu_ids, nr_node_ids);
@@ -199,7 +240,7 @@ void __cpuinit numa_set_node(int cpu, int node) 
{

	int *cpu_to_node_map = early_per_cpu_ptr(x86_cpu_to_node_map);



	if (node != NUMA_NO_NODE)

	if (cpu_pda(cpu) && node != NUMA_NO_NODE)

		cpu_pda(cpu)->nodenumber = node;



	if (cpu_to_node_map)

arch/x86/kernel/setup64.c

+5 −3
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ 
#include <linux/bitops.h>

#include <linux/module.h>

#include <linux/kgdb.h>

#include <linux/topology.h>

#include <asm/pda.h>

#include <asm/pgtable.h>

#include <asm/processor.h>
@@ -34,9 +35,8 @@ struct boot_params boot_params; 


cpumask_t cpu_initialized __cpuinitdata = CPU_MASK_NONE;



struct x8664_pda *_cpu_pda[NR_CPUS] __read_mostly;

struct x8664_pda **_cpu_pda __read_mostly;

EXPORT_SYMBOL(_cpu_pda);

struct x8664_pda boot_cpu_pda[NR_CPUS] __cacheline_aligned;



struct desc_ptr idt_descr = { 256 * 16 - 1, (unsigned long) idt_table };
@@ -114,8 +114,10 @@ void pda_init(int cpu) 
			__get_free_pages(GFP_ATOMIC, IRQSTACK_ORDER);

		if (!pda->irqstackptr)

			panic("cannot allocate irqstack for cpu %d", cpu); 

	}



		if (pda->nodenumber == 0 && cpu_to_node(cpu) != NUMA_NO_NODE)

			pda->nodenumber = cpu_to_node(cpu);

	}



	pda->irqstackptr += IRQSTACKSIZE-64;

}

arch/x86/kernel/smpboot.c

+46 −13
Original line number Diff line number Diff line
@@ -816,6 +816,43 @@ static void __cpuinit do_fork_idle(struct work_struct *work) 
	complete(&c_idle->done);

}



/*

 * Allocate node local memory for the AP pda.

 *

 * Must be called after the _cpu_pda pointer table is initialized.

 */

static int __cpuinit get_local_pda(int cpu)

{

	struct x8664_pda *oldpda, *newpda;

	unsigned long size = sizeof(struct x8664_pda);

	int node = cpu_to_node(cpu);



	if (cpu_pda(cpu) && !cpu_pda(cpu)->in_bootmem)

		return 0;



	oldpda = cpu_pda(cpu);

	newpda = kmalloc_node(size, GFP_ATOMIC, node);

	if (!newpda) {

		printk(KERN_ERR "Could not allocate node local PDA "

			"for CPU %d on node %d\n", cpu, node);



		if (oldpda)

			return 0;	/* have a usable pda */

		else

			return -1;

	}



	if (oldpda) {

		memcpy(newpda, oldpda, size);

		if (!after_bootmem)

			free_bootmem((unsigned long)oldpda, size);

	}



	newpda->in_bootmem = 0;

	cpu_pda(cpu) = newpda;

	return 0;

}



static int __cpuinit do_boot_cpu(int apicid, int cpu)

/*

 * NOTE - on most systems this is a PHYSICAL apic ID, but on multiquad
@@ -841,19 +878,11 @@ static int __cpuinit do_boot_cpu(int apicid, int cpu) 
	}



	/* Allocate node local memory for AP pdas */

	if (cpu_pda(cpu) == &boot_cpu_pda[cpu]) {

		struct x8664_pda *newpda, *pda;

		int node = cpu_to_node(cpu);

		pda = cpu_pda(cpu);

		newpda = kmalloc_node(sizeof(struct x8664_pda), GFP_ATOMIC,

				      node);

		if (newpda) {

			memcpy(newpda, pda, sizeof(struct x8664_pda));

			cpu_pda(cpu) = newpda;

		} else

			printk(KERN_ERR

		"Could not allocate node local PDA for CPU %d on node %d\n",

				cpu, node);

	if (cpu > 0) {

		boot_error = get_local_pda(cpu);

		if (boot_error)

			goto restore_state;

			/* if can't get pda memory, can't start cpu */

	}

#endif
@@ -972,6 +1001,8 @@ do_rest: 
		}

	}



restore_state:



	if (boot_error) {

		/* Try to put things back the way they were before ... */

		unmap_cpu_to_logical_apicid(cpu);
@@ -1347,6 +1378,8 @@ __init void prefill_possible_map(void) 


	for (i = 0; i < possible; i++)

		cpu_set(i, cpu_possible_map);



	nr_cpu_ids = possible;

}



static void __ref remove_cpu_from_maps(int cpu)

include/asm-x86/pda.h

+3 −3
Original line number Diff line number Diff line
@@ -22,7 +22,8 @@ struct x8664_pda { 
					   offset 40!!! */

#endif

	char *irqstackptr;

	int nodenumber;			/* number of current node */

	short nodenumber;		/* number of current node (32k max) */

	short in_bootmem;		/* pda lives in bootmem */

	unsigned int __softirq_pending;

	unsigned int __nmi_count;	/* number of NMI on this CPUs */

	short mmu_state;
@@ -38,8 +39,7 @@ struct x8664_pda { 
	unsigned irq_spurious_count;

} ____cacheline_aligned_in_smp;



extern struct x8664_pda *_cpu_pda[];

extern struct x8664_pda boot_cpu_pda[];

extern struct x8664_pda **_cpu_pda;

extern void pda_init(int);



#define cpu_pda(i) (_cpu_pda[i])

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