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 static inline int cmma_test_essa(void)
39 register unsigned long tmp asm("0") = 0;
40 register int rc asm("1") = -EOPNOTSUPP;
43 " .insn rrf,0xb9ab0000,%1,%1,0,0\n"
47 : "+&d" (rc), "+&d" (tmp));
51 void __init cmma_init(void)
59 static inline void set_page_unstable(struct page *page, int order)
63 for (i = 0; i < (1 << order); i++)
64 asm volatile(".insn rrf,0xb9ab0000,%0,%1,%2,0"
66 : "a" (page_to_phys(page + i)),
67 "i" (ESSA_SET_UNUSED));
70 void arch_free_page(struct page *page, int order)
74 set_page_unstable(page, order);
77 static inline void set_page_stable(struct page *page, int order)
81 for (i = 0; i < (1 << order); i++)
82 asm volatile(".insn rrf,0xb9ab0000,%0,%1,%2,0"
84 : "a" (page_to_phys(page + i)),
85 "i" (ESSA_SET_STABLE));
88 void arch_alloc_page(struct page *page, int order)
92 set_page_stable(page, order);
95 void arch_set_page_states(int make_stable)
97 unsigned long flags, order, t;
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);
112 set_page_stable(page, order);
114 set_page_unstable(page, order);
117 spin_unlock_irqrestore(&zone->lock, flags);