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Commit 7919e91b authored by Martin Schwidefsky's avatar Martin Schwidefsky
Browse files

s390/mm: zero page cache synonyms for zEC12 



To avoid cache synonyms on System zEC12 32 independent zero pages are
required, one for each combination for bits 2**12 to 2**16 of the virtual
address. To avoid wasting too much memory on small virtual systems the
number of zero pages is limited to 4 if the memory size is less or equal
to 64MB.

Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent f752ac4d

arch/s390/mm/init.c

+9 −1
Original line number Diff line number Diff line
@@ -63,10 +63,18 @@ static unsigned long __init setup_zero_pages(void) 
		break;

	case 0x2097:	/* z10 */

	case 0x2098:	/* z10 */

	default:

	case 0x2817:	/* z196 */

	case 0x2818:	/* z196 */

		order = 2;

		break;

	case 0x2827:	/* zEC12 */

	default:

		order = 5;

		break;

	}

	/* Limit number of empty zero pages for small memory sizes */

	if (order > 2 && totalram_pages <= 16384)

		order = 2;



	empty_zero_page = __get_free_pages(GFP_KERNEL | __GFP_ZERO, order);

	if (!empty_zero_page)