Author: alc
Date: Wed Feb 25 07:52:53 2009
New Revision: 189024
URL: http://svn.freebsd.org/changeset/base/189024
Log:
Prior to r188331 a map entry's last read offset was only updated by a hard
fault. In r188331 this update was relocated because of synchronization
changes to a place where it would occur on both hard and soft faults. This
change again restricts the update to hard faults.
Modified:
head/sys/vm/vm_fault.c
Modified: head/sys/vm/vm_fault.c
==============================================================================
--- head/sys/vm/vm_fault.c Wed Feb 25 01:49:01 2009 (r189023)
+++ head/sys/vm/vm_fault.c Wed Feb 25 07:52:53 2009 (r189024)
@@ -868,13 +868,17 @@ vnode_locked:
}
}
/*
- * update lastr imperfectly (we do not know how much
- * getpages will actually read), but good enough.
+ * If the page was filled by a pager, update the map entry's
+ * last read offset. Since the pager does not return the
+ * actual set of pages that it read, this update is based on
+ * the requested set. Typically, the requested and actual
+ * sets are the same.
*
* XXX The following assignment modifies the map
* without holding a write lock on it.
*/
- fs.entry->lastr = fs.pindex + faultcount - behind;
+ if (hardfault)
+ fs.entry->lastr = fs.pindex + faultcount - behind;
if (prot & VM_PROT_WRITE) {
vm_object_set_writeable_dirty(fs.object);
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