Author: kib
Date: Thu Jul 11 05:58:28 2013
New Revision: 253191
URL: http://svnweb.freebsd.org/changeset/base/253191
Log:
The vm_fault() should not be allowed to proceed on the map entry which
is being wired now. The entry wired count is changed to non-zero in
advance, before the map lock is dropped. This makes the vm_fault() to
perceive the entry as wired, and breaks the fragment which moves the
wire count from the shadowed page, to the upper page, making the code
unwiring non-wired page.
On the other hand, the vm_fault() calls from vm_fault_wire() should be
allowed to proceed, so only drain MAP_ENTRY_IN_TRANSITION from
vm_fault() when wiring_thread is not current.
Reported and tested by: pho
Reviewed by: alc
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Modified:
head/sys/vm/vm_fault.c
Modified: head/sys/vm/vm_fault.c
==============================================================================
--- head/sys/vm/vm_fault.c Thu Jul 11 05:55:08 2013 (r253190)
+++ head/sys/vm/vm_fault.c Thu Jul 11 05:58:28 2013 (r253191)
@@ -280,6 +280,19 @@ RetryFault:;
(u_long)vaddr);
}
+ if (fs.entry->eflags & MAP_ENTRY_IN_TRANSITION &&
+ fs.entry->wiring_thread != curthread) {
+ vm_map_unlock_read(fs.map);
+ vm_map_lock(fs.map);
+ if (vm_map_lookup_entry(fs.map, vaddr, &fs.entry) &&
+ (fs.entry->eflags & MAP_ENTRY_IN_TRANSITION)) {
+ fs.entry->eflags |= MAP_ENTRY_NEEDS_WAKEUP;
+ vm_map_unlock_and_wait(fs.map, 0);
+ } else
+ vm_map_unlock(fs.map);
+ goto RetryFault;
+ }
+
/*
* Make a reference to this object to prevent its disposal while we
* are messing with it. Once we have the reference, the map is free
_______________________________________________
svn-src-head@freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/svn-src-head
To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
