1 files changed, 34 insertions, 10 deletions

diff --git a/usr/src/uts/i86pc/vm/hat_i86.c b/usr/src/uts/i86pc/vm/hat_i86.c
index 8da02a4c36..40b033d0e4 100644
--- a/usr/src/uts/i86pc/vm/hat_i86.c
+++ b/usr/src/uts/i86pc/vm/hat_i86.c
@@ -27,6 +27,7 @@
  */
 /*
  * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
+ * Copyright 2012 Joyent, Inc.  All rights reserved.
  */
 
 /*
@@ -3350,15 +3351,13 @@ hati_page_unmap(page_t *pp, htable_t *ht, uint_t entry)
 
 extern int	vpm_enable;
 /*
- * Unload all translations to a page. If the page is a subpage of a large
+ * Unload translations to a page. If the page is a subpage of a large
  * page, the large page mappings are also removed.
- *
- * The forceflags are unused.
+ * If unloadflag is HAT_CURPROC_PGUNLOAD, then we only unload the translation
+ * for the current process, otherwise all translations are unloaded.
  */
-
-/*ARGSUSED*/
 static int
-hati_pageunload(struct page *pp, uint_t pg_szcd, uint_t forceflag)
+hati_pageunload(struct page *pp, uint_t pg_szcd, uint_t unloadflag)
 {
 	page_t		*cur_pp = pp;
 	hment_t		*hm;
@@ -3366,6 +3365,8 @@ hati_pageunload(struct page *pp, uint_t pg_szcd, uint_t forceflag)
 	htable_t	*ht;
 	uint_t		entry;
 	level_t		level;
+	struct hat	*curhat;
+	ulong_t		cnt;
 
 	XPV_DISALLOW_MIGRATE();
 
@@ -3375,6 +3376,9 @@ hati_pageunload(struct page *pp, uint_t pg_szcd, uint_t forceflag)
 	++curthread->t_hatdepth;
 	ASSERT(curthread->t_hatdepth < 16);
 
+	if (unloadflag == HAT_CURPROC_PGUNLOAD)
+		curhat = curthread->t_procp->p_as->a_hat;
+
 #if defined(__amd64)
 	/*
 	 * clear the vpm ref.
@@ -3387,6 +3391,8 @@ hati_pageunload(struct page *pp, uint_t pg_szcd, uint_t forceflag)
 	 * The loop with next_size handles pages with multiple pagesize mappings
 	 */
 next_size:
+	if (unloadflag == HAT_CURPROC_PGUNLOAD)
+		cnt = hat_page_getshare(cur_pp);
 	for (;;) {
 
 		/*
@@ -3398,6 +3404,7 @@ next_size:
 			if (hm == NULL) {
 				x86_hm_exit(cur_pp);
 
+curproc_done:
 				/*
 				 * If not part of a larger page, we're done.
 				 */
@@ -3424,8 +3431,21 @@ next_size:
 			 * If this mapping size matches, remove it.
 			 */
 			level = ht->ht_level;
-			if (level == pg_szcd)
-				break;
+			if (level == pg_szcd) {
+				if (unloadflag != HAT_CURPROC_PGUNLOAD ||
+				    ht->ht_hat == curhat)
+					break;
+				/*
+				 * unloadflag == HAT_CURPROC_PGUNLOAD but it's
+				 * not the hat for the current process. Leave
+				 * entry in place. Also do a safety check to
+				 * ensure we don't get in an infinite loop
+				 */
+				if (cnt-- == 0) {
+					x86_hm_exit(cur_pp);
+					goto curproc_done;
+				}
+			}
 		}
 
 		/*
@@ -3435,14 +3455,18 @@ next_size:
 		hm = hati_page_unmap(cur_pp, ht, entry);
 		if (hm != NULL)
 			hment_free(hm);
+
+		/* Perform check above for being part of a larger page. */
+		if (unloadflag == HAT_CURPROC_PGUNLOAD)
+			goto curproc_done;
 	}
 }
 
 int
-hat_pageunload(struct page *pp, uint_t forceflag)
+hat_pageunload(struct page *pp, uint_t unloadflag)
 {
 	ASSERT(PAGE_EXCL(pp));
-	return (hati_pageunload(pp, 0, forceflag));
+	return (hati_pageunload(pp, 0, unloadflag));
 }
 
 /*