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Commit f1cfdb55 authored by David S. Miller's avatar David S. Miller
Browse files

[SPARC64]: Document and fix calculation of pages_avail. 



It should be set to the total number of pages that the
system will really have available after things like
initmem, the bootmem map, and initrd are freed up.

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 0f3e2504

arch/sparc64/mm/init.c

+23 −2
Original line number Diff line number Diff line
@@ -938,6 +938,20 @@ static void __init trim_pavail(unsigned long *cur_size_p, 
	}

}



/* About pages_avail, this is the value we will use to calculate

 * the zholes_size[] argument given to free_area_init_node().  The

 * page allocator uses this to calculate nr_kernel_pages,

 * nr_all_pages and zone->present_pages.  On NUMA it is used

 * to calculate zone->min_unmapped_pages and zone->min_slab_pages.

 *

 * So this number should really be set to what the page allocator

 * actually ends up with.  This means:

 * 1) It should include bootmem map pages, we'll release those.

 * 2) It should not include the kernel image, except for the

 *    __init sections which we will also release.

 * 3) It should include the initrd image, since we'll release

 *    that too.

 */

static unsigned long __init bootmem_init(unsigned long *pages_avail,

					 unsigned long phys_base)

{
@@ -1024,7 +1038,6 @@ static unsigned long __init bootmem_init(unsigned long *pages_avail, 
			initrd_start, initrd_end);

#endif

		reserve_bootmem(initrd_start, size);

		*pages_avail -= PAGE_ALIGN(size) >> PAGE_SHIFT;



		initrd_start += PAGE_OFFSET;

		initrd_end += PAGE_OFFSET;
@@ -1037,6 +1050,11 @@ static unsigned long __init bootmem_init(unsigned long *pages_avail, 
	reserve_bootmem(kern_base, kern_size);

	*pages_avail -= PAGE_ALIGN(kern_size) >> PAGE_SHIFT;



	/* Add back in the initmem pages. */

	size = ((unsigned long)(__init_end) & PAGE_MASK) -

		PAGE_ALIGN((unsigned long)__init_begin);

	*pages_avail += size >> PAGE_SHIFT;



	/* Reserve the bootmem map.   We do not account for it

	 * in pages_avail because we will release that memory

	 * in free_all_bootmem.
@@ -1047,7 +1065,6 @@ static unsigned long __init bootmem_init(unsigned long *pages_avail, 
		    (bootmap_pfn << PAGE_SHIFT), size);

#endif

	reserve_bootmem((bootmap_pfn << PAGE_SHIFT), size);

	*pages_avail -= PAGE_ALIGN(size) >> PAGE_SHIFT;



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

		unsigned long start_pfn, end_pfn;
@@ -1539,6 +1556,10 @@ void __init mem_init(void) 
#ifdef CONFIG_DEBUG_BOOTMEM

	prom_printf("mem_init: Calling free_all_bootmem().\n");

#endif



	/* We subtract one to account for the mem_map_zero page

	 * allocated below.

	 */

	totalram_pages = num_physpages = free_all_bootmem() - 1;



	/*