LXR linux/arch/s390/mm/page-states.c

   1/*
   2 * Copyright IBM Corp. 2008
   3 *
   4 * Guest page hinting for unused pages.
   5 *
   6 * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
   7 */
   8
   9#include <linux/kernel.h>
  10#include <linux/errno.h>
  11#include <linux/types.h>
  12#include <linux/mm.h>
  13#include <linux/gfp.h>
  14#include <linux/init.h>
  15
  16#define ESSA_SET_STABLE         1
  17#define ESSA_SET_UNUSED         2
  18
  19static int cmma_flag = 1;
  20
  21static int __init cmma(char *str)
  22{
  23        char *parm;
  24
  25        parm = strstrip(str);
  26        if (strcmp(parm, "yes") == 0 || strcmp(parm, "on") == 0) {
  27                cmma_flag = 1;
  28                return 1;
  29        }
  30        cmma_flag = 0;
  31        if (strcmp(parm, "no") == 0 || strcmp(parm, "off") == 0)
  32                return 1;
  33        return 0;
  34}
  35__setup("cmma=", cmma);
  36
  37static inline int cmma_test_essa(void)
  38{
  39        register unsigned long tmp asm("0") = 0;
  40        register int rc asm("1") = -EOPNOTSUPP;
  41
  42        asm volatile(
  43                "       .insn rrf,0xb9ab0000,%1,%1,0,0\n"
  44                "0:     la      %0,0\n"
  45                "1:\n"
  46                EX_TABLE(0b,1b)
  47                : "+&d" (rc), "+&d" (tmp));
  48        return rc;
  49}
  50
  51void __init cmma_init(void)
  52{
  53        if (!cmma_flag)
  54                return;
  55        if (cmma_test_essa())
  56                cmma_flag = 0;
  57}
  58
  59static inline void set_page_unstable(struct page *page, int order)
  60{
  61        int i, rc;
  62
  63        for (i = 0; i < (1 << order); i++)
  64                asm volatile(".insn rrf,0xb9ab0000,%0,%1,%2,0"
  65                             : "=&d" (rc)
  66                             : "a" (page_to_phys(page + i)),
  67                               "i" (ESSA_SET_UNUSED));
  68}
  69
  70void arch_free_page(struct page *page, int order)
  71{
  72        if (!cmma_flag)
  73                return;
  74        set_page_unstable(page, order);
  75}
  76
  77static inline void set_page_stable(struct page *page, int order)
  78{
  79        int i, rc;
  80
  81        for (i = 0; i < (1 << order); i++)
  82                asm volatile(".insn rrf,0xb9ab0000,%0,%1,%2,0"
  83                             : "=&d" (rc)
  84                             : "a" (page_to_phys(page + i)),
  85                               "i" (ESSA_SET_STABLE));
  86}
  87
  88void arch_alloc_page(struct page *page, int order)
  89{
  90        if (!cmma_flag)
  91                return;
  92        set_page_stable(page, order);
  93}
  94
  95void arch_set_page_states(int make_stable)
  96{
  97        unsigned long flags, order, t;
  98        struct list_head *l;
  99        struct page *page;
 100        struct zone *zone;
 101
 102        if (!cmma_flag)
 103                return;
 104        if (make_stable)
 105                drain_local_pages(NULL);
 106        for_each_populated_zone(zone) {
 107                spin_lock_irqsave(&zone->lock, flags);
 108                for_each_migratetype_order(order, t) {
 109                        list_for_each(l, &zone->free_area[order].free_list[t]) {
 110                                page = list_entry(l, struct page, lru);
 111                                if (make_stable)
 112                                        set_page_stable(page, order);
 113                                else
 114                                        set_page_unstable(page, order);
 115                        }
 116                }
 117                spin_unlock_irqrestore(&zone->lock, flags);
 118        }
 119}
 120