2 * Copyright IBM Corp. 2008
4 * Guest page hinting for unused pages.
6 * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
9 #include <linux/kernel.h>
10 #include <linux/errno.h>
11 #include <linux/types.h>
13 #include <linux/gfp.h>
14 #include <linux/init.h>
16 #define ESSA_SET_STABLE 1
17 #define ESSA_SET_UNUSED 2
19 static int cmma_flag = 1;
21 static int __init cmma(char *str)
26 if (strcmp(parm, "yes") == 0 || strcmp(parm, "on") == 0) {
31 if (strcmp(parm, "no") == 0 || strcmp(parm, "off") == 0)
35 __setup("cmma=", cmma);
37 void __init cmma_init(void)
39 register unsigned long tmp asm("0") = 0;
40 register int rc asm("1") = -EOPNOTSUPP;
45 " .insn rrf,0xb9ab0000,%1,%1,0,0\n"
49 : "+&d" (rc), "+&d" (tmp));
54 static inline void set_page_unstable(struct page *page, int order)
58 for (i = 0; i < (1 << order); i++)
59 asm volatile(".insn rrf,0xb9ab0000,%0,%1,%2,0"
61 : "a" (page_to_phys(page + i)),
62 "i" (ESSA_SET_UNUSED));
65 void arch_free_page(struct page *page, int order)
69 set_page_unstable(page, order);
72 static inline void set_page_stable(struct page *page, int order)
76 for (i = 0; i < (1 << order); i++)
77 asm volatile(".insn rrf,0xb9ab0000,%0,%1,%2,0"
79 : "a" (page_to_phys(page + i)),
80 "i" (ESSA_SET_STABLE));
83 void arch_alloc_page(struct page *page, int order)
87 set_page_stable(page, order);
90 void arch_set_page_states(int make_stable)
92 unsigned long flags, order, t;
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);
107 set_page_stable(page, order);
109 set_page_unstable(page, order);
112 spin_unlock_irqrestore(&zone->lock, flags);