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Date:      Wed, 11 Jun 2014 16:11:12 +0000 (UTC)
From:      Alan Cox <alc@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r267364 - head/sys/vm
Message-ID:  <201406111611.s5BGBCHU058618@svn.freebsd.org>
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Author: alc
Date: Wed Jun 11 16:11:12 2014
New Revision: 267364
URL: http://svnweb.freebsd.org/changeset/base/267364

Log:
  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

Modified:
  head/sys/vm/vm_reserv.c

Modified: head/sys/vm/vm_reserv.c
==============================================================================
--- head/sys/vm/vm_reserv.c	Wed Jun 11 14:53:58 2014	(r267363)
+++ head/sys/vm/vm_reserv.c	Wed Jun 11 16:11:12 2014	(r267364)
@@ -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
 	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
 		    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 i
 	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 i
 		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_
 		 * 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;

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