3 files changed, 64 insertions, 0 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index e87bdbfbcc75..844e9a654d0b 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -497,6 +497,13 @@ and is between 256 and 4096 characters. It is defined in the file
                         Also note the kernel might malfunction if you disable
                         some critical bits.
 
+        cmo_free_hint=  [PPC] Format: { yes | no }
+                        Specify whether pages are marked as being inactive
+                        when they are freed.  This is used in CMO environments
+                        to determine OS memory pressure for page stealing by
+                        a hypervisor.
+                        Default: yes
+
         code_bytes      [X86] How many bytes of object code to print
                         in an oops report.
                         Range: 0 - 8192
diff --git a/arch/powerpc/include/asm/page.h b/arch/powerpc/include/asm/page.h
index 32cbf16f10ea..4940662ee87e 100644
--- a/arch/powerpc/include/asm/page.h
+++ b/arch/powerpc/include/asm/page.h
@@ -231,6 +231,11 @@ extern void copy_user_page(void *to, void *from, unsigned long vaddr,
                 struct page *p);
 extern int page_is_ram(unsigned long pfn);
 
+#ifdef CONFIG_PPC_SMLPAR
+void arch_free_page(struct page *page, int order);
+#define HAVE_ARCH_FREE_PAGE
+#endif
+
 struct vm_area_struct;
 
 typedef struct page *pgtable_t;
diff --git a/arch/powerpc/platforms/pseries/lpar.c b/arch/powerpc/platforms/pseries/lpar.c
index 52a80e5840e8..e3139fa5e556 100644
--- a/arch/powerpc/platforms/pseries/lpar.c
+++ b/arch/powerpc/platforms/pseries/lpar.c
@@ -609,3 +609,55 @@ void __init hpte_init_lpar(void)
         ppc_md.flush_hash_range = pSeries_lpar_flush_hash_range;
         ppc_md.hpte_clear_all   = pSeries_lpar_hptab_clear;
 }
+
+#ifdef CONFIG_PPC_SMLPAR
+#define CMO_FREE_HINT_DEFAULT 1
+static int cmo_free_hint_flag = CMO_FREE_HINT_DEFAULT;
+
+static int __init cmo_free_hint(char *str)
+{
+        char *parm;
+        parm = strstrip(str);
+
+        if (strcasecmp(parm, "no") == 0 || strcasecmp(parm, "off") == 0) {
+                printk(KERN_INFO "cmo_free_hint: CMO free page hinting is not active.\n");
+                cmo_free_hint_flag = 0;
+                return 1;
+        }
+
+        cmo_free_hint_flag = 1;
+        printk(KERN_INFO "cmo_free_hint: CMO free page hinting is active.\n");
+
+        if (strcasecmp(parm, "yes") == 0 || strcasecmp(parm, "on") == 0)
+                return 1;
+
+        return 0;
+}
+
+__setup("cmo_free_hint=", cmo_free_hint);
+
+static void pSeries_set_page_state(struct page *page, int order,
+                                   unsigned long state)
+{
+        int i, j;
+        unsigned long cmo_page_sz, addr;
+
+        cmo_page_sz = cmo_get_page_size();
+        addr = __pa((unsigned long)page_address(page));
+
+        for (i = 0; i < (1 << order); i++, addr += PAGE_SIZE) {
+                for (j = 0; j < PAGE_SIZE; j += cmo_page_sz)
+                        plpar_hcall_norets(H_PAGE_INIT, state, addr + j, 0);
+        }
+}
+
+void arch_free_page(struct page *page, int order)
+{
+        if (!cmo_free_hint_flag || !firmware_has_feature(FW_FEATURE_CMO))
+                return;
+
+        pSeries_set_page_state(page, order, H_PAGE_SET_UNUSED);
+}
+EXPORT_SYMBOL(arch_free_page);
+
+#endif