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
  37void __init cmma_init(void)
  38{
  39        register unsigned long tmp asm("0") = 0;
  40        register int rc asm("1") = -EOPNOTSUPP;
  41
  42        if (!cmma_flag)
  43                return;
  44        asm volatile(
  45                "       .insn rrf,0xb9ab0000,%1,%1,0,0\n"
  46                "0:     la      %0,0\n"
  47                "1:\n"
  48                EX_TABLE(0b,1b)
  49                : "+&d" (rc), "+&d" (tmp));
  50        if (rc)
  51                cmma_flag = 0;
  52}
  53
  54static inline void set_page_unstable(struct page *page, int order)
  55{
  56        int i, rc;
  57
  58        for (i = 0; i < (1 << order); i++)
  59                asm volatile(".insn rrf,0xb9ab0000,%0,%1,%2,0"
  60                             : "=&d" (rc)
  61                             : "a" (page_to_phys(page + i)),
  62                               "i" (ESSA_SET_UNUSED));
  63}
  64
  65void arch_free_page(struct page *page, int order)
  66{
  67        if (!cmma_flag)
  68                return;
  69        set_page_unstable(page, order);
  70}
  71
  72static inline void set_page_stable(struct page *page, int order)
  73{
  74        int i, rc;
  75
  76        for (i = 0; i < (1 << order); i++)
  77                asm volatile(".insn rrf,0xb9ab0000,%0,%1,%2,0"
  78                             : "=&d" (rc)
  79                             : "a" (page_to_phys(page + i)),
  80                               "i" (ESSA_SET_STABLE));
  81}
  82
  83void arch_alloc_page(struct page *page, int order)
  84{
  85        if (!cmma_flag)
  86                return;
  87        set_page_stable(page, order);
  88}
  89
  90void arch_set_page_states(int make_stable)
  91{
  92        unsigned long flags, order, t;
  93        struct list_head *l;
  94        struct page *page;
  95        struct zone *zone;
  96
  97        if (!cmma_flag)
  98                return;
  99        if (make_stable)
 100                drain_local_pages(NULL);
 101        for_each_populated_zone(zone) {
 102                spin_lock_irqsave(&zone->lock, flags);
 103                for_each_migratetype_order(order, t) {
 104                        list_for_each(l, &zone->free_area[order].free_list[t]) {
 105                                page = list_entry(l, struct page, lru);
 106                                if (make_stable)
 107                                        set_page_stable(page, order);
 108                                else
 109                                        set_page_unstable(page, order);
 110                        }
 111                }
 112                spin_unlock_irqrestore(&zone->lock, flags);
 113        }
 114}
 115