Dave McCracken
2010-Jun-09 15:49 UTC
[Xen-devel] [Linux PATCH] Mark hugepages to the hypervisor to speed up mapping
--- next/arch/x86/xen/mmu.c 2010-06-01 11:41:54.000000000 -0500
+++ next-fh//arch/x86/xen/mmu.c 2010-06-02 08:45:01.000000000 -0500
@@ -2531,3 +2531,51 @@ static int __init xen_mmu_debugfs(void)
fs_initcall(xen_mmu_debugfs);
#endif /* CONFIG_XEN_DEBUG_FS */
+
+static int mark_ok = 1;
+
+int arch_prepare_hugepage(struct page *page)
+{
+ struct mmuext_op op;
+ unsigned long pfn, mfn, m;
+ int i;
+ int rc;
+
+ pfn = page_to_pfn(page);
+ mfn = pfn_to_mfn(pfn);
+ if (mfn & ((HPAGE_SIZE/PAGE_SIZE)-1)) {
+ printk("Guest pages are not properly aligned to use hugepages\n");
+ return 1;
+ }
+ for (i = 0, m = mfn; i < HPAGE_SIZE/PAGE_SIZE; i++, pfn++, m++) {
+ if (pfn_to_mfn(pfn) != m) {
+ printk("Guest pages are not properly aligned to use hugepages\n");
+ return 1;
+ }
+ }
+ /* It''s ok if this fails. We just fall back to the slow refcounting
*/
+ if (mark_ok) {
+ op.cmd = MMUEXT_MARK_SUPER;
+ op.arg1.mfn = mfn;
+ rc = HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF);
+ if (rc) {
+ if (rc == -ENOSYS) {
+ mark_ok = 0;
+ return 0;
+ }
+ return 1;
+ }
+ }
+ return 0;
+}
+
+void arch_release_hugepage(struct page *page)
+{
+ struct mmuext_op op;
+
+ if (mark_ok) {
+ op.cmd = MMUEXT_UNMARK_SUPER;
+ op.arg1.mfn = pfn_to_mfn(page_to_pfn(page));
+ HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF);
+ }
+}
--- next/arch/x86/include/asm/hugetlb.h 2010-06-01 11:41:54.000000000 -0500
+++ next-fh//arch/x86/include/asm/hugetlb.h 2010-06-02 08:37:58.000000000 -0500
@@ -95,6 +95,10 @@ static inline int huge_ptep_set_access_f
return changed;
}
+#ifdef CONFIG_XEN
+int arch_prepare_hugepage(struct page *page);
+void arch_release_hugepage(struct page *page);
+#else
static inline int arch_prepare_hugepage(struct page *page)
{
return 0;
@@ -103,5 +107,6 @@ static inline int arch_prepare_hugepage(
static inline void arch_release_hugepage(struct page *page)
{
}
+#endif
#endif /* _ASM_X86_HUGETLB_H */
--- next/include/xen/interface/xen.h 2010-06-01 11:41:59.000000000 -0500
+++ next-fh//include/xen/interface/xen.h 2010-06-02 08:38:50.000000000 -0500
@@ -167,6 +167,19 @@
* cmd: MMUEXT_SET_LDT
* linear_addr: Linear address of LDT base (NB. must be page-aligned).
* nr_ents: Number of entries in LDT.
+ *
+ * cmd: MMUEXT_CLEAR_PAGE
+ * mfn: Machine frame number to be cleared.
+ *
+ * cmd: MMUEXT_COPY_PAGE
+ * mfn: Machine frame number of the destination page.
+ * src_mfn: Machine frame number of the source page.
+ *
+ * cmd: MMUEXT_MARK_SUPER
+ * mfn: Machine frame number of head of superpage to be marked.
+ *
+ * cmd: MMUEXT_UNMARK_SUPER
+ * mfn: Machine frame number of head of superpage to be cleared.
*/
#define MMUEXT_PIN_L1_TABLE 0
#define MMUEXT_PIN_L2_TABLE 1
@@ -183,6 +196,10 @@
#define MMUEXT_FLUSH_CACHE 12
#define MMUEXT_SET_LDT 13
#define MMUEXT_NEW_USER_BASEPTR 15
+#define MMUEXT_CLEAR_PAGE 16
+#define MMUEXT_COPY_PAGE 17
+#define MMUEXT_MARK_SUPER 19
+#define MMUEXT_UNMARK_SUPER 20
#ifndef __ASSEMBLY__
#include <linux/types.h>
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