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Add MAP_INHERIT_ZERO

This commit is contained in:
christos 2014-07-18 12:36:57 +00:00
parent 33f99f08ae
commit e93cdeae9b
2 changed files with 37 additions and 3 deletions
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3
sys/sys/mman.h
View File

@ -1,4 +1,4 @@
/* $NetBSD: mman.h,v 1.46 2014/06/30 21:46:33 matt Exp $ */
/* $NetBSD: mman.h,v 1.47 2014/07/18 12:36:57 christos Exp $ */
/*-
* Copyright (c) 1982, 1986, 1993
@ -161,6 +161,7 @@ typedef __off_t off_t; /* file offset */
#define MAP_INHERIT_NONE 2 /* absent from child */
#define MAP_INHERIT_DONATE_COPY 3 /* copy and delete -- not
implemented in UVM */
#define MAP_INHERIT_ZERO 4 /* zero in child */
#define MAP_INHERIT_DEFAULT MAP_INHERIT_COPY
#endif

37
sys/uvm/uvm_map.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: uvm_map.c,v 1.329 2014/07/18 12:19:09 christos Exp $ */
/* $NetBSD: uvm_map.c,v 1.330 2014/07/18 12:36:57 christos Exp $ */
/*
* Copyright (c) 1997 Charles D. Cranor and Washington University.
@ -66,7 +66,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: uvm_map.c,v 1.329 2014/07/18 12:19:09 christos Exp $");
__KERNEL_RCSID(0, "$NetBSD: uvm_map.c,v 1.330 2014/07/18 12:36:57 christos Exp $");
#include "opt_ddb.h"
#include "opt_uvmhist.h"
@ -3097,6 +3097,7 @@ uvm_map_inherit(struct vm_map *map, vaddr_t start, vaddr_t end,
case MAP_INHERIT_NONE:
case MAP_INHERIT_COPY:
case MAP_INHERIT_SHARE:
case MAP_INHERIT_ZERO:
break;
default:
UVMHIST_LOG(maphist,"<- done (INVALID ARG)",0,0,0,0);
@ -4345,6 +4346,35 @@ uvm_mapent_forkcopy(struct vm_map *new_map, struct vm_map *old_map,
}
}
/*
* zero the mapping: the new entry will be zero initialized
*/
static void
uvm_mapent_forkzero(struct vm_map *new_map, struct vm_map *old_map,
struct vm_map_entry *old_entry)
{
struct vm_map_entry *new_entry;
new_entry = uvm_mapent_clone(new_map, old_entry, 0);
new_entry->etype |=
(UVM_ET_COPYONWRITE|UVM_ET_NEEDSCOPY);
if (new_entry->aref.ar_amap) {
uvm_map_unreference_amap(new_entry, 0);
new_entry->aref.ar_pageoff = 0;
new_entry->aref.ar_amap = NULL;
}
if (UVM_ET_ISOBJ(new_entry)) {
if (new_entry->object.uvm_obj->pgops->pgo_detach)
new_entry->object.uvm_obj->pgops->pgo_detach(
new_entry->object.uvm_obj);
new_entry->object.uvm_obj = NULL;
new_entry->etype &= ~UVM_ET_OBJ;
}
}
/*
* F O R K - m a i n e n t r y p o i n t
*/
@ -4405,6 +4435,9 @@ uvmspace_fork(struct vmspace *vm1)
uvm_mapent_forkcopy(new_map, old_map, old_entry);
break;
case MAP_INHERIT_ZERO:
uvm_mapent_forkzero(new_map, old_map, old_entry);
break;
default:
KASSERT(0);
break;