Add an MD page flag for tracking if a page is cacheable or not, so that

we don't flush all mappings of a physical page in order to make it
virtually cachable again, if it is already cachable.

2 files changed, 7 insertions, 1 deletions

diff --git a/sys/sparc64/include/pmap.h b/sys/sparc64/include/pmap.h
index 46ed059..d347fc8 100644
--- a/sys/sparc64/include/pmap.h
+++ b/sys/sparc64/include/pmap.h
@@ -52,6 +52,8 @@
 
 #define	PMAP_CONTEXT_MAX	8192
 
+#define	PG_UNCACHEABLE		(1<<0)
+
 #define	pmap_resident_count(pm)	(pm->pm_stats.resident_count)
 
 typedef	struct pmap *pmap_t;
@@ -59,6 +61,7 @@ typedef	struct pmap *pmap_t;
 struct md_page {
 	STAILQ_HEAD(, tte) tte_list;
 	int	colors[DCACHE_COLORS];
+	int	flags;
 };
 
 struct pmap {
diff --git a/sys/sparc64/sparc64/pmap.c b/sys/sparc64/sparc64/pmap.c
index 52f9fda..e3f0355 100644
--- a/sys/sparc64/sparc64/pmap.c
+++ b/sys/sparc64/sparc64/pmap.c
@@ -517,6 +517,7 @@ pmap_init(vm_offset_t phys_start, vm_offset_t phys_end)
 
 		m = &vm_page_array[i];
 		STAILQ_INIT(&m->md.tte_list);
+		m->md.flags = 0;
 	}
 
 	for (i = 0; i < translations_size; i++) {
@@ -605,6 +606,7 @@ pmap_cache_enter(vm_page_t m, vm_offset_t va)
 		    TTE_GET_VA(tp));
 	}
 	dcache_page_inval(VM_PAGE_TO_PHYS(m));
+	m->md.flags |= PG_UNCACHEABLE;
 	return (0);
 }
 
@@ -624,13 +626,14 @@ pmap_cache_remove(vm_page_t m, vm_offset_t va)
 		if (m->md.colors[i] != 0)
 			c++;
 	}
-	if (c != 1)
+	if (c != 1 || (m->md.flags & PG_UNCACHEABLE) == 0)
 		return;
 	STAILQ_FOREACH(tp, &m->md.tte_list, tte_link) {
 		tp->tte_data |= TD_CV;
 		tlb_page_demap(TLB_DTLB | TLB_ITLB, TTE_GET_PMAP(tp),
 		    TTE_GET_VA(tp));
 	}
+	m->md.flags &= ~PG_UNCACHEABLE;
 }
 
 /*