diff options
| -rw-r--r-- | vm/vm_map.c | 27 |
1 files changed, 26 insertions, 1 deletions
diff --git a/vm/vm_map.c b/vm/vm_map.c index 6bfc527f..8a9c6988 100644 --- a/vm/vm_map.c +++ b/vm/vm_map.c @@ -1555,9 +1555,21 @@ static void vm_map_pageable_scan( * while we have it unlocked. We cannot trust user threads * to do the same. * + * We set the in_transition bit in the entries to prevent + * them from getting coalesced with their neighbors at the + * same time as we're accessing them. + * * HACK HACK HACK HACK */ if (vm_map_pmap(map) == kernel_pmap) { + for (entry = start_entry; + (entry != vm_map_to_entry(map)) && + (entry->vme_end <= end); + entry = entry->vme_next) { + assert(!entry->in_transition); + entry->in_transition = TRUE; + entry->needs_wakeup = FALSE; + } vm_map_unlock(map); /* trust me ... */ } else { vm_map_lock_set_recursive(map); @@ -1583,6 +1595,19 @@ static void vm_map_pageable_scan( if (vm_map_pmap(map) == kernel_pmap) { vm_map_lock(map); + for (entry = start_entry; + (entry != vm_map_to_entry(map)) && + (entry->vme_end <= end); + entry = entry->vme_next) { + assert(entry->in_transition); + entry->in_transition = FALSE; + /* + * Nothing should've tried to access + * this VM region while we had the map + * unlocked. + */ + assert(!entry->needs_wakeup); + } } else { vm_map_lock_clear_recursive(map); } @@ -5037,7 +5062,7 @@ vm_map_coalesce_entry( /* * Get rid of the entry without changing any wirings or the pmap, - * and without altering map->size. + * and without altering map->size. */ prev->vme_end = entry->vme_end; vm_map_entry_unlink(map, entry); |