Signed-off-by: Andi Kleen <ak@suse.de>

---
 arch/x86/mm/pageattr-test.c |    6 +++++-
 arch/x86/mm/pageattr_32.c   |   23 +++++++++++++++++++++--
 2 files changed, 26 insertions(+), 3 deletions(-)

Index: linux/arch/x86/mm/pageattr-test.c
===================================================================
--- linux.orig/arch/x86/mm/pageattr-test.c
+++ linux/arch/x86/mm/pageattr-test.c
@@ -15,7 +15,7 @@
 #include <asm/kdebug.h>
 
 enum {
-	NTEST = 400,
+	NTEST = 5,
 #ifdef CONFIG_X86_64
 	LOWEST_LEVEL = 4,
 	LPS = (1 << PMD_SHIFT),
@@ -137,8 +137,10 @@ static __init int exercise_pageattr(void
 		unsigned long pfn = random32() % max_mapped;
 		addr[i] = (unsigned long)__va(pfn << PAGE_SHIFT);
 		len[i] = random32() % 100;
+#if 0
 		len[i] = min_t(unsigned long, len[i], max_mapped - pfn - 1);
 		if (len[i] == 0)
+#endif
 			len[i] = 1;
 
 		pte = NULL;
@@ -167,6 +169,8 @@ static __init int exercise_pageattr(void
 			continue;
 		}
 
+		printk("%lx len %d prot1 %Lx\n", addr[i], len[i],
+			pgprot_val(pte_pgprot(pte0)));
 		err = change_page_attr(virt_to_page(addr[i]), len[i],
 			    pte_pgprot(pte_clrhuge(pte_clrglobal(pte0))));
 		if (err < 0) {
Index: linux/arch/x86/mm/pageattr_32.c
===================================================================
--- linux.orig/arch/x86/mm/pageattr_32.c
+++ linux/arch/x86/mm/pageattr_32.c
@@ -220,6 +220,11 @@ static void set_tlb_flush(unsigned long 
 		full_flush = FLUSH_TLB;
 }
 
+void track(struct page *p, char *what)
+{
+	printk("cpa kpte %s %lx to %lu\n", what, page_to_pfn(p), page_private(p));
+}
+
 static int
 __change_page_attr(struct page *page, pgprot_t prot)
 { 
@@ -237,8 +242,11 @@ __change_page_attr(struct page *page, pg
 	if (!kpte)
 		return -EINVAL;
 
+
 	oldprot = pte_pgprot(*kpte);
 	kpte_page = virt_to_page(kpte);
+
+
 	BUG_ON(PageLRU(kpte_page));
 	BUG_ON(PageCompound(kpte_page));
 
@@ -259,10 +267,17 @@ __change_page_attr(struct page *page, pg
 	ref_prot = canon_pgprot(ref_prot);
 	prot = canon_pgprot(prot);
 
+	printk("cpa %lx %Lx->%Lx ref %Lx level %d ref %lu\n", address,
+		pgprot_val(oldprot), pgprot_val(prot),
+		pgprot_val(ref_prot), level, page_private(kpte_page));
+
 	if (pgprot_val(prot) != pgprot_val(ref_prot)) {
 		if (level == 3) {
-			if (pgprot_val(oldprot) == pgprot_val(ref_prot))
+			if (pgprot_val(oldprot) == pgprot_val(ref_prot)) {
 				page_private(kpte_page)++;
+				track(kpte_page, "change from ref_prot");
+			} else
+				track(kpte_page, "change from non-ref");
 			set_pte_atomic(kpte, mk_pte(page, prot)); 
 		} else {
 			struct page *split;
@@ -272,12 +287,15 @@ __change_page_attr(struct page *page, pg
 			set_pmd_pte(kpte,address,mk_pte(split, ref_prot));
 			kpte_page = split;
 			page_private(kpte_page)++;
+			track(kpte_page, "split");
 		}
 	} else if (level == 3) {
 		if (pgprot_val(oldprot) != pgprot_val(ref_prot)) {
 			BUG_ON(page_private(kpte_page) <= 0);
 			page_private(kpte_page)--;
-		}
+			track(kpte_page, "change from non ref to ref");
+		} else
+			track(kpte_page, "change from ref to ref level 3");
 		set_pte_atomic(kpte, mk_pte(page, ref_prot));
 	} else {
 		/*
@@ -300,6 +318,7 @@ __change_page_attr(struct page *page, pg
 		if (cpu_has_pse && (page_private(kpte_page) == 0)) {
 			save_page(kpte_page);
 			paravirt_release_pt(page_to_pfn(kpte_page));
+			track(kpte_page, "reverting");
 			revert_page(kpte_page, address, ref_prot);
 		}
 	}