Correct a bug in the management of the population map on big-endian

machines.  Specifically, there was a mismatch between how the routine
allocation and deallocation operations accessed the population map
and how the aggressively optimized reservation-breaking operation
accessed it.  So, problems only occurred when reservations were broken.
This change makes the routine operations access the population map in
the same way as the reservation breaking operation.

This bug was introduced in r259999.

PR:		187080
Tested by:	jmg (on an "armeb" machine)
Sponsored by:	EMC / Isilon Storage Division

1 files changed, 48 insertions, 8 deletions

diff --git a/sys/vm/vm_reserv.c b/sys/vm/vm_reserv.c
index c8de47e..2a38d01 100644
--- a/sys/vm/vm_reserv.c
+++ b/sys/vm/vm_reserv.c
@@ -108,6 +108,46 @@ typedef	u_long		popmap_t;
 #define	NPOPMAP		howmany(VM_LEVEL_0_NPAGES, NBPOPMAP)
 
 /*
+ * Clear a bit in the population map.
+ */
+static __inline void
+popmap_clear(popmap_t popmap[], int i)
+{
+
+	popmap[i / NBPOPMAP] &= ~(1UL << (i % NBPOPMAP));
+}
+
+/*
+ * Set a bit in the population map.
+ */
+static __inline void
+popmap_set(popmap_t popmap[], int i)
+{
+
+	popmap[i / NBPOPMAP] |= 1UL << (i % NBPOPMAP);
+}
+
+/*
+ * Is a bit in the population map clear?
+ */
+static __inline boolean_t
+popmap_is_clear(popmap_t popmap[], int i)
+{
+
+	return ((popmap[i / NBPOPMAP] & (1UL << (i % NBPOPMAP))) == 0);
+}
+
+/*
+ * Is a bit in the population map set?
+ */
+static __inline boolean_t
+popmap_is_set(popmap_t popmap[], int i)
+{
+
+	return ((popmap[i / NBPOPMAP] & (1UL << (i % NBPOPMAP))) != 0);
+}
+
+/*
  * The reservation structure
  *
  * A reservation structure is constructed whenever a large physical page is
@@ -241,7 +281,7 @@ vm_reserv_depopulate(vm_reserv_t rv, int index)
 	mtx_assert(&vm_page_queue_free_mtx, MA_OWNED);
 	KASSERT(rv->object != NULL,
 	    ("vm_reserv_depopulate: reserv %p is free", rv));
-	KASSERT(isset(rv->popmap, index),
+	KASSERT(popmap_is_set(rv->popmap, index),
 	    ("vm_reserv_depopulate: reserv %p's popmap[%d] is clear", rv,
 	    index));
 	KASSERT(rv->popcnt > 0,
@@ -255,7 +295,7 @@ vm_reserv_depopulate(vm_reserv_t rv, int index)
 		    rv));
 		rv->pages->psind = 0;
 	}
-	clrbit(rv->popmap, index);
+	popmap_clear(rv->popmap, index);
 	rv->popcnt--;
 	if (rv->popcnt == 0) {
 		LIST_REMOVE(rv, objq);
@@ -302,7 +342,7 @@ vm_reserv_populate(vm_reserv_t rv, int index)
 	mtx_assert(&vm_page_queue_free_mtx, MA_OWNED);
 	KASSERT(rv->object != NULL,
 	    ("vm_reserv_populate: reserv %p is free", rv));
-	KASSERT(isclr(rv->popmap, index),
+	KASSERT(popmap_is_clear(rv->popmap, index),
 	    ("vm_reserv_populate: reserv %p's popmap[%d] is set", rv,
 	    index));
 	KASSERT(rv->popcnt < VM_LEVEL_0_NPAGES,
@@ -313,7 +353,7 @@ vm_reserv_populate(vm_reserv_t rv, int index)
 		TAILQ_REMOVE(&vm_rvq_partpop, rv, partpopq);
 		rv->inpartpopq = FALSE;
 	}
-	setbit(rv->popmap, index);
+	popmap_set(rv->popmap, index);
 	rv->popcnt++;
 	if (rv->popcnt < VM_LEVEL_0_NPAGES) {
 		rv->inpartpopq = TRUE;
@@ -503,7 +543,7 @@ found:
 		return (NULL);
 	/* Handle vm_page_rename(m, new_object, ...). */
 	for (i = 0; i < npages; i++)
-		if (isset(rv->popmap, index + i))
+		if (popmap_is_set(rv->popmap, index + i))
 			return (NULL);
 	for (i = 0; i < npages; i++)
 		vm_reserv_populate(rv, index + i);
@@ -628,7 +668,7 @@ found:
 	index = VM_RESERV_INDEX(object, pindex);
 	m = &rv->pages[index];
 	/* Handle vm_page_rename(m, new_object, ...). */
-	if (isset(rv->popmap, index))
+	if (popmap_is_set(rv->popmap, index))
 		return (NULL);
 	vm_reserv_populate(rv, index);
 	return (m);
@@ -662,9 +702,9 @@ vm_reserv_break(vm_reserv_t rv, vm_page_t m)
 		 * to the physical memory allocator.
 		 */
 		i = m - rv->pages;
-		KASSERT(isclr(rv->popmap, i),
+		KASSERT(popmap_is_clear(rv->popmap, i),
 		    ("vm_reserv_break: reserv %p's popmap is corrupted", rv));
-		setbit(rv->popmap, i);
+		popmap_set(rv->popmap, i);
 		rv->popcnt++;
 	}
 	i = hi = 0;