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Commit 45e576b1 authored by Martin Schwidefsky's avatar Martin Schwidefsky
Browse files

[S390] guest page hinting light 



Use the existing arch_alloc_page/arch_free_page callbacks to do
the guest page state transitions between stable and unused.

Acked-by: default avatarRik van Riel <riel@redhat.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 74c76c84

arch/s390/Kconfig

+7 −0
Original line number Diff line number Diff line
@@ -430,6 +430,13 @@ config CMM_IUCV 
	  Select this option to enable the special message interface to

	  the cooperative memory management.



config PAGE_STATES

	bool "Unused page notification"

	help

	  This enables the notification of unused pages to the

	  hypervisor. The ESSA instruction is used to do the states

	  changes between a page that has content and the unused state.



config VIRT_TIMER

	bool "Virtual CPU timer support"

	help

arch/s390/mm/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -5,3 +5,4 @@ 
obj-y	 := init.o fault.o extmem.o mmap.o vmem.o pgtable.o

obj-$(CONFIG_CMM) += cmm.o

obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o

obj-$(CONFIG_PAGE_STATES) += page-states.o

arch/s390/mm/init.c

+3 −0
Original line number Diff line number Diff line
@@ -126,6 +126,9 @@ void __init mem_init(void) 
        /* clear the zero-page */

        memset(empty_zero_page, 0, PAGE_SIZE);



	/* Setup guest page hinting */

	cmma_init();



	/* this will put all low memory onto the freelists */

	totalram_pages += free_all_bootmem();

arch/s390/mm/page-states.c

0 → 100644
+79 −0
Original line number Diff line number Diff line 
/*

 * arch/s390/mm/page-states.c

 *

 * Copyright IBM Corp. 2008

 *

 * Guest page hinting for unused pages.

 *

 * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>

 */



#include <linux/kernel.h>

#include <linux/errno.h>

#include <linux/types.h>

#include <linux/mm.h>

#include <linux/init.h>



#define ESSA_SET_STABLE		1

#define ESSA_SET_UNUSED		2



static int cmma_flag;



static int __init cmma(char *str)

{

	char *parm;

	parm = strstrip(str);

	if (strcmp(parm, "yes") == 0 || strcmp(parm, "on") == 0) {

		cmma_flag = 1;

		return 1;

	}

	cmma_flag = 0;

	if (strcmp(parm, "no") == 0 || strcmp(parm, "off") == 0)

		return 1;

	return 0;

}



__setup("cmma=", cmma);



void __init cmma_init(void)

{

	register unsigned long tmp asm("0") = 0;

	register int rc asm("1") = -EOPNOTSUPP;



	if (!cmma_flag)

		return;

	asm volatile(

		"       .insn rrf,0xb9ab0000,%1,%1,0,0\n"

		"0:     la      %0,0\n"

		"1:\n"

		EX_TABLE(0b,1b)

		: "+&d" (rc), "+&d" (tmp));

	if (rc)

		cmma_flag = 0;

}



void arch_free_page(struct page *page, int order)

{

	int i, rc;



	if (!cmma_flag)

		return;

	for (i = 0; i < (1 << order); i++)

		asm volatile(".insn rrf,0xb9ab0000,%0,%1,%2,0"

			     : "=&d" (rc)

			     : "a" ((page_to_pfn(page) + i) << PAGE_SHIFT),

			       "i" (ESSA_SET_UNUSED));

}



void arch_alloc_page(struct page *page, int order)

{

	int i, rc;



	if (!cmma_flag)

		return;

	for (i = 0; i < (1 << order); i++)

		asm volatile(".insn rrf,0xb9ab0000,%0,%1,%2,0"

			     : "=&d" (rc)

			     : "a" ((page_to_pfn(page) + i) << PAGE_SHIFT),

			       "i" (ESSA_SET_STABLE));

}

include/asm-s390/page.h

+11 −0
Original line number Diff line number Diff line
@@ -125,6 +125,17 @@ page_get_storage_key(unsigned long addr) 
	return skey;

}



#ifdef CONFIG_PAGE_STATES



struct page;

void arch_free_page(struct page *page, int order);

void arch_alloc_page(struct page *page, int order);



#define HAVE_ARCH_FREE_PAGE

#define HAVE_ARCH_ALLOC_PAGE



#endif



#endif /* !__ASSEMBLY__ */



/* to align the pointer to the (next) page boundary */