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Commit 5f5d8405 authored by Tejun Heo's avatar Tejun Heo
Browse files

x86: separate out setup_pcpu_4k() from setup_per_cpu_areas() 



Impact: modularize percpu first chunk allocation

x86 is gonna have a few different strategies for the first chunk
allocation.  Modularize it by separating out the current allocation
mechanism into pcpu_alloc_bootmem() and setup_pcpu_4k().

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent 8d408b4b

arch/x86/kernel/setup_percpu.c

+102 −42
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ 
#include <linux/crash_dump.h>

#include <linux/smp.h>

#include <linux/topology.h>

#include <linux/pfn.h>

#include <asm/sections.h>

#include <asm/processor.h>

#include <asm/setup.h>
@@ -41,6 +42,52 @@ unsigned long __per_cpu_offset[NR_CPUS] __read_mostly = { 
};

EXPORT_SYMBOL(__per_cpu_offset);



/**

 * pcpu_alloc_bootmem - NUMA friendly alloc_bootmem wrapper for percpu

 * @cpu: cpu to allocate for

 * @size: size allocation in bytes

 * @align: alignment

 *

 * Allocate @size bytes aligned at @align for cpu @cpu.  This wrapper

 * does the right thing for NUMA regardless of the current

 * configuration.

 *

 * RETURNS:

 * Pointer to the allocated area on success, NULL on failure.

 */

static void * __init pcpu_alloc_bootmem(unsigned int cpu, unsigned long size,

					unsigned long align)

{

	const unsigned long goal = __pa(MAX_DMA_ADDRESS);

#ifdef CONFIG_NEED_MULTIPLE_NODES

	int node = early_cpu_to_node(cpu);

	void *ptr;



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

		ptr = __alloc_bootmem_nopanic(size, align, goal);

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

			cpu, node);

		pr_debug("per cpu data for cpu%d %lu bytes at %016lx\n",

			 cpu, size, __pa(ptr));

	} else {

		ptr = __alloc_bootmem_node_nopanic(NODE_DATA(node),

						   size, align, goal);

		pr_debug("per cpu data for cpu%d %lu bytes on node%d at "

			 "%016lx\n", cpu, size, node, __pa(ptr));

	}

	return ptr;

#else

	return __alloc_bootmem_nopanic(size, align, goal);

#endif

}



/*

 * 4k page allocator

 *

 * This is the basic allocator.  Static percpu area is allocated

 * page-by-page and most of initialization is done by the generic

 * setup function.

 */

static struct page **pcpu4k_pages __initdata;

static int pcpu4k_nr_static_pages __initdata;
@@ -56,6 +103,51 @@ static void __init pcpu4k_populate_pte(unsigned long addr) 
	populate_extra_pte(addr);

}



static ssize_t __init setup_pcpu_4k(size_t static_size)

{

	size_t pages_size;

	unsigned int cpu;

	int i, j;

	ssize_t ret;



	pcpu4k_nr_static_pages = PFN_UP(static_size);



	/* unaligned allocations can't be freed, round up to page size */

	pages_size = PFN_ALIGN(pcpu4k_nr_static_pages * num_possible_cpus()

			       * sizeof(pcpu4k_pages[0]));

	pcpu4k_pages = alloc_bootmem(pages_size);



	/* allocate and copy */

	j = 0;

	for_each_possible_cpu(cpu)

		for (i = 0; i < pcpu4k_nr_static_pages; i++) {

			void *ptr;



			ptr = pcpu_alloc_bootmem(cpu, PAGE_SIZE, PAGE_SIZE);

			if (!ptr)

				goto enomem;



			memcpy(ptr, __per_cpu_load + i * PAGE_SIZE, PAGE_SIZE);

			pcpu4k_pages[j++] = virt_to_page(ptr);

		}



	/* we're ready, commit */

	pr_info("PERCPU: Allocated %d 4k pages, static data %zu bytes\n",

		pcpu4k_nr_static_pages, static_size);



	ret = pcpu_setup_first_chunk(pcpu4k_get_page, static_size, 0, 0, NULL,

				     pcpu4k_populate_pte);

	goto out_free_ar;



enomem:

	while (--j >= 0)

		free_bootmem(__pa(page_address(pcpu4k_pages[j])), PAGE_SIZE);

	ret = -ENOMEM;

out_free_ar:

	free_bootmem(__pa(pcpu4k_pages), pages_size);

	return ret;

}



static inline void setup_percpu_segment(int cpu)

{

#ifdef CONFIG_X86_32
@@ -76,56 +168,24 @@ static inline void setup_percpu_segment(int cpu) 
 */

void __init setup_per_cpu_areas(void)

{

	ssize_t size = __per_cpu_end - __per_cpu_start;

	unsigned int nr_cpu_pages = DIV_ROUND_UP(size, PAGE_SIZE);

	static struct page **pages;

	size_t pages_size;

	unsigned int cpu, i, j;

	size_t static_size = __per_cpu_end - __per_cpu_start;

	unsigned int cpu;

	unsigned long delta;

	size_t pcpu_unit_size;

	ssize_t ret;



	pr_info("NR_CPUS:%d nr_cpumask_bits:%d nr_cpu_ids:%d nr_node_ids:%d\n",

		NR_CPUS, nr_cpumask_bits, nr_cpu_ids, nr_node_ids);

	pr_info("PERCPU: Allocating %zd bytes for static per cpu data\n", size);



	pages_size = nr_cpu_pages * num_possible_cpus() * sizeof(pages[0]);

	pages = alloc_bootmem(pages_size);



	j = 0;

	for_each_possible_cpu(cpu) {

		void *ptr;



		for (i = 0; i < nr_cpu_pages; i++) {

#ifndef CONFIG_NEED_MULTIPLE_NODES

			ptr = alloc_bootmem_pages(PAGE_SIZE);

#else

			int node = early_cpu_to_node(cpu);



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

				ptr = alloc_bootmem_pages(PAGE_SIZE);

				pr_info("cpu %d has no node %d or node-local "

					"memory\n", cpu, node);

				pr_debug("per cpu data for cpu%d at %016lx\n",

					 cpu, __pa(ptr));

			} else {

				ptr = alloc_bootmem_pages_node(NODE_DATA(node),

							       PAGE_SIZE);

				pr_debug("per cpu data for cpu%d on node%d "

					 "at %016lx\n", cpu, node, __pa(ptr));

			}

#endif

			memcpy(ptr, __per_cpu_load + i * PAGE_SIZE, PAGE_SIZE);

			pages[j++] = virt_to_page(ptr);

		}

	}



	pcpu4k_pages = pages;

	pcpu4k_nr_static_pages = nr_cpu_pages;

	pcpu_unit_size = pcpu_setup_first_chunk(pcpu4k_get_page, size, 0, 0,

						NULL, pcpu4k_populate_pte);

	/* allocate percpu area */

	ret = setup_pcpu_4k(static_size);

	if (ret < 0)

		panic("cannot allocate static percpu area (%zu bytes, err=%zd)",

		      static_size, ret);



	free_bootmem(__pa(pages), pages_size);

	pcpu_unit_size = ret;



	/* alrighty, percpu areas up and running */

	delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start;

	for_each_possible_cpu(cpu) {

		per_cpu_offset(cpu) = delta + cpu * pcpu_unit_size;