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authorRobert Jennings <rcj@linux.vnet.ibm.com>2009-04-15 05:55:32 +0000
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2009-05-21 15:43:58 +1000
commit14f966e79445015cd89d0fa0ceb6b33702e951b6 (patch)
treeb45546523e909b3d0a05df188c7494af3ce94ca1
parentd69a78d7daada190b42269a73daabe32a5e138a6 (diff)
powerpc/pseries: CMO unused page hinting
Adds support for the "unused" page hint which can be used in shared memory partitions to flag pages not in use, which will then be stolen before active pages by the hypervisor when memory needs to be moved to LPARs in need of additional memory. Failure to mark pages as 'unused' makes the LPAR slower to give up unused memory to other partitions. This adds the kernel parameter 'cmo_free_hint' to disable this functionality. Signed-off-by: Brian King <brking@linux.vnet.ibm.com> Signed-off-by: Robert Jennings <rcj@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
-rw-r--r--Documentation/kernel-parameters.txt7
-rw-r--r--arch/powerpc/include/asm/page.h5
-rw-r--r--arch/powerpc/platforms/pseries/lpar.c52
3 files changed, 64 insertions, 0 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index e87bdbfbcc7..844e9a654d0 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 32cbf16f10e..4940662ee87 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 52a80e5840e..e3139fa5e55 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