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Commit 4769843b authored by Ingo Molnar's avatar Ingo Molnar
Browse files

x86, 32-bit: clean up find_low_pfn_range() 



Impact: cleanup

Split find_low_pfn_range() into two functions:

 - lowmem_pfn_init()
 - highmem_pfn_init()

The former gets called if all of RAM fits into lowmem,
otherwise we call highmem_pfn_init().

Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 3023533d

arch/x86/mm/init_32.c

+79 −58
Original line number Diff line number Diff line
@@ -675,24 +675,59 @@ static int __init parse_highmem(char *arg) 
}

early_param("highmem", parse_highmem);



#define MSG_HIGHMEM_TOO_BIG \

	"highmem size (%luMB) is bigger than pages available (%luMB)!\n"



#define MSG_LOWMEM_TOO_SMALL \

	"highmem size (%luMB) results in <64MB lowmem, ignoring it!\n"

/*

 * Determine low and high memory ranges:

 * All of RAM fits into lowmem - but if user wants highmem

 * artificially via the highmem=x boot parameter then create

 * it:

 */

void __init find_low_pfn_range(void)

void __init lowmem_pfn_init(void)

{

	/* it could update max_pfn */

	if (highmem_pages == -1)

		highmem_pages = 0;

#ifdef CONFIG_HIGHMEM

	if (highmem_pages >= max_pfn) {

		printk(KERN_ERR MSG_HIGHMEM_TOO_BIG,

			pages_to_mb(highmem_pages), pages_to_mb(max_pfn));

		highmem_pages = 0;

	}

	if (highmem_pages) {

		if (max_low_pfn - highmem_pages < 64*1024*1024/PAGE_SIZE) {

			printk(KERN_ERR MSG_LOWMEM_TOO_SMALL,

				pages_to_mb(highmem_pages));

			highmem_pages = 0;

		}

		max_low_pfn -= highmem_pages;

	}

#else

	if (highmem_pages)

		printk(KERN_ERR "ignoring highmem size on non-highmem kernel!\n");

#endif

}



	/* max_low_pfn is 0, we already have early_res support */

#define MSG_HIGHMEM_TOO_SMALL \

	"only %luMB highmem pages available, ignoring highmem size of %luMB!\n"



	max_low_pfn = max_pfn;

	if (max_low_pfn > MAXMEM_PFN) {

#define MSG_HIGHMEM_TRIMMED \

	"Warning: only 4GB will be used. Use a HIGHMEM64G enabled kernel!\n"

/*

 * We have more RAM than fits into lowmem - we try to put it into

 * highmem, also taking the highmem=x boot parameter into account:

 */

void __init highmem_pfn_init(void)

{

	if (highmem_pages == -1)

		highmem_pages = max_pfn - MAXMEM_PFN;



	if (highmem_pages + MAXMEM_PFN < max_pfn)

		max_pfn = MAXMEM_PFN + highmem_pages;



	if (highmem_pages + MAXMEM_PFN > max_pfn) {

			printk(KERN_WARNING "only %luMB highmem pages "

				"available, ignoring highmem size of %luMB.\n",

		printk(KERN_WARNING MSG_HIGHMEM_TOO_SMALL,

			pages_to_mb(max_pfn - MAXMEM_PFN),

			pages_to_mb(highmem_pages));

		highmem_pages = 0;
@@ -700,11 +735,9 @@ void __init find_low_pfn_range(void) 
	max_low_pfn = MAXMEM_PFN;

#ifndef CONFIG_HIGHMEM

	/* Maximum memory usable is what is directly addressable */

		printk(KERN_WARNING "Warning only %ldMB will be used.\n",

					MAXMEM>>20);

	printk(KERN_WARNING "Warning only %ldMB will be used.\n", MAXMEM>>20);

	if (max_pfn > MAX_NONPAE_PFN)

			printk(KERN_WARNING

				 "Use a HIGHMEM64G enabled kernel.\n");

		printk(KERN_WARNING "Use a HIGHMEM64G enabled kernel.\n");

	else

		printk(KERN_WARNING "Use a HIGHMEM enabled kernel.\n");

	max_pfn = MAXMEM_PFN;
@@ -712,38 +745,26 @@ void __init find_low_pfn_range(void) 
#ifndef CONFIG_HIGHMEM64G

	if (max_pfn > MAX_NONPAE_PFN) {

		max_pfn = MAX_NONPAE_PFN;

			printk(KERN_WARNING "Warning only 4GB will be used."

				"Use a HIGHMEM64G enabled kernel.\n");

		printk(KERN_WARNING MSG_HIGHMEM_TRIMMED);

	}

#endif /* !CONFIG_HIGHMEM64G */

#endif /* !CONFIG_HIGHMEM */

	} else {

		if (highmem_pages == -1)

			highmem_pages = 0;

#ifdef CONFIG_HIGHMEM

		if (highmem_pages >= max_pfn) {

			printk(KERN_ERR "highmem size specified (%luMB) is "

				"bigger than pages available (%luMB)!.\n",

				pages_to_mb(highmem_pages),

				pages_to_mb(max_pfn));

			highmem_pages = 0;

		}

		if (highmem_pages) {

			if (max_low_pfn - highmem_pages <

			    64*1024*1024/PAGE_SIZE){

				printk(KERN_ERR "highmem size %luMB results in "

				"smaller than 64MB lowmem, ignoring it.\n"

					, pages_to_mb(highmem_pages));

				highmem_pages = 0;

			}

			max_low_pfn -= highmem_pages;

		}

#else

		if (highmem_pages)

			printk(KERN_ERR "ignoring highmem size on non-highmem"

					" kernel!\n");

#endif

}



/*

 * Determine low and high memory ranges:

 */

void __init find_low_pfn_range(void)

{

	/* it could update max_pfn */



	/* max_low_pfn is 0, we already have early_res support */

	max_low_pfn = max_pfn;



	if (max_low_pfn > MAXMEM_PFN)

		highmem_pfn_init();

	else

		lowmem_pfn_init();

}



#ifndef CONFIG_NEED_MULTIPLE_NODES