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[src/trunk]: src/sys/uvm - uvmspace_exec(), uvmspace_free(): if pmap_remove_a...
details: https://anonhg.NetBSD.org/src/rev/622acb2ace69
branches: trunk
changeset: 745857:622acb2ace69
user: ad <ad%NetBSD.org@localhost>
date: Sat Mar 14 14:15:43 2020 +0000
description:
- uvmspace_exec(), uvmspace_free(): if pmap_remove_all() returns true the
pmap is emptied. Pass UVM_FLAG_VAONLY when clearing out the map and avoid
needless extra work to tear down each mapping individually.
- uvm_map_lookup_entry(): remove the code to do a linear scan of map entries
for small maps, in preference to using the RB tree. It's questionable,
and I think the code is almost never triggered because the average number
of map entries has probably exceeded the hard-coded threshold for quite
some time.
- vm_map_entry: get it aligned on a cacheline boundary, and cluster fields
used during rbtree lookup at the beginning.
diffstat:
sys/uvm/uvm_map.c | 125 +++++++++++++++--------------------------------------
sys/uvm/uvm_map.h | 22 +++++---
2 files changed, 48 insertions(+), 99 deletions(-)
diffs (280 lines):
diff -r 43c248b1ffe8 -r 622acb2ace69 sys/uvm/uvm_map.c
--- a/sys/uvm/uvm_map.c Sat Mar 14 14:05:42 2020 +0000
+++ b/sys/uvm/uvm_map.c Sat Mar 14 14:15:43 2020 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: uvm_map.c,v 1.372 2020/02/23 15:46:43 ad Exp $ */
+/* $NetBSD: uvm_map.c,v 1.373 2020/03/14 14:15:43 ad 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 1.372 2020/02/23 15:46:43 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: uvm_map.c,v 1.373 2020/03/14 14:15:43 ad Exp $");
#include "opt_ddb.h"
#include "opt_pax.h"
@@ -141,10 +141,8 @@
UVMMAP_EVCNT_DEFINE(map_call)
UVMMAP_EVCNT_DEFINE(mlk_call)
UVMMAP_EVCNT_DEFINE(mlk_hint)
-UVMMAP_EVCNT_DEFINE(mlk_list)
UVMMAP_EVCNT_DEFINE(mlk_tree)
UVMMAP_EVCNT_DEFINE(mlk_treeloop)
-UVMMAP_EVCNT_DEFINE(mlk_listloop)
const char vmmapbsy[] = "vmmapbsy";
@@ -823,8 +821,8 @@
uvm_mapent_copy(struct vm_map_entry *src, struct vm_map_entry *dst)
{
- memcpy(dst, src, ((char *)&src->uvm_map_entry_stop_copy) -
- ((char *)src));
+ memcpy(dst, src, sizeof(*dst));
+ dst->flags = 0;
}
#if defined(DEBUG)
@@ -940,7 +938,7 @@
*/
pool_cache_bootstrap(&uvm_map_entry_cache, sizeof(struct vm_map_entry),
- 0, 0, 0, "vmmpepl", NULL, IPL_NONE, NULL, NULL, NULL);
+ coherency_unit, 0, 0, "vmmpepl", NULL, IPL_NONE, NULL, NULL, NULL);
pool_cache_bootstrap(&uvm_vmspace_cache, sizeof(struct vmspace),
0, 0, 0, "vmsppl", NULL, IPL_NONE, NULL, NULL, NULL);
}
@@ -1679,7 +1677,6 @@
struct vm_map_entry **entry /* OUT */)
{
struct vm_map_entry *cur;
- bool use_tree = false;
UVMHIST_FUNC("uvm_map_lookup_entry");
UVMHIST_CALLED(maphist);
@@ -1687,95 +1684,41 @@
(uintptr_t)map, address, (uintptr_t)entry, 0);
/*
- * start looking either from the head of the
- * list, or from the hint.
+ * make a quick check to see if we are already looking at
+ * the entry we want (which is usually the case). note also
+ * that we don't need to save the hint here... it is the
+ * same hint (unless we are at the header, in which case the
+ * hint didn't buy us anything anyway).
*/
cur = map->hint;
-
- if (cur == &map->header)
- cur = cur->next;
-
UVMMAP_EVCNT_INCR(mlk_call);
- if (address >= cur->start) {
-
- /*
- * go from hint to end of list.
- *
- * but first, make a quick check to see if
- * we are already looking at the entry we
- * want (which is usually the case).
- * note also that we don't need to save the hint
- * here... it is the same hint (unless we are
- * at the header, in which case the hint didn't
- * buy us anything anyway).
- */
-
- if (cur != &map->header && cur->end > address) {
- UVMMAP_EVCNT_INCR(mlk_hint);
- *entry = cur;
- UVMHIST_LOG(maphist,"<- got it via hint (%#jx)",
- (uintptr_t)cur, 0, 0, 0);
- uvm_mapent_check(*entry);
- return (true);
- }
-
- if (map->nentries > 15)
- use_tree = true;
- } else {
-
- /*
- * invalid hint. use tree.
- */
- use_tree = true;
+ if (cur != &map->header &&
+ address >= cur->start && cur->end > address) {
+ UVMMAP_EVCNT_INCR(mlk_hint);
+ *entry = cur;
+ UVMHIST_LOG(maphist,"<- got it via hint (%#jx)",
+ (uintptr_t)cur, 0, 0, 0);
+ uvm_mapent_check(*entry);
+ return (true);
}
-
uvm_map_check(map, __func__);
- if (use_tree) {
- /*
- * Simple lookup in the tree. Happens when the hint is
- * invalid, or nentries reach a threshold.
- */
- UVMMAP_EVCNT_INCR(mlk_tree);
- if (uvm_map_lookup_entry_bytree(map, address, entry)) {
- goto got;
- } else {
- goto failed;
- }
- }
-
/*
- * search linearly
+ * lookup in the tree.
*/
- UVMMAP_EVCNT_INCR(mlk_list);
- while (cur != &map->header) {
- UVMMAP_EVCNT_INCR(mlk_listloop);
- if (cur->end > address) {
- if (address >= cur->start) {
- /*
- * save this lookup for future
- * hints, and return
- */
-
- *entry = cur;
-got:
- SAVE_HINT(map, map->hint, *entry);
- UVMHIST_LOG(maphist,"<- search got it (%#jx)",
- (uintptr_t)cur, 0, 0, 0);
- KDASSERT((*entry)->start <= address);
- KDASSERT(address < (*entry)->end);
- uvm_mapent_check(*entry);
- return (true);
- }
- break;
- }
- cur = cur->next;
+ UVMMAP_EVCNT_INCR(mlk_tree);
+ if (__predict_true(uvm_map_lookup_entry_bytree(map, address, entry))) {
+ SAVE_HINT(map, map->hint, *entry);
+ UVMHIST_LOG(maphist,"<- search got it (%#jx)",
+ (uintptr_t)cur, 0, 0, 0);
+ KDASSERT((*entry)->start <= address);
+ KDASSERT(address < (*entry)->end);
+ uvm_mapent_check(*entry);
+ return (true);
}
- *entry = cur->prev;
-failed:
- SAVE_HINT(map, map->hint, *entry);
+
UVMHIST_LOG(maphist,"<- failed!",0,0,0,0);
KDASSERT((*entry) == &map->header || (*entry)->end <= address);
KDASSERT((*entry)->next == &map->header ||
@@ -4176,6 +4119,7 @@
struct proc *p = l->l_proc;
struct vmspace *nvm, *ovm = p->p_vmspace;
struct vm_map *map;
+ int flags;
KASSERT(ovm != NULL);
#ifdef __HAVE_CPU_VMSPACE_EXEC
@@ -4214,8 +4158,8 @@
* now unmap the old program
*/
- pmap_remove_all(map->pmap);
- uvm_unmap(map, vm_map_min(map), vm_map_max(map));
+ flags = pmap_remove_all(map->pmap) ? UVM_FLAG_VAONLY : 0;
+ uvm_unmap1(map, vm_map_min(map), vm_map_max(map), flags);
KASSERT(map->header.prev == &map->header);
KASSERT(map->nentries == 0);
@@ -4271,6 +4215,7 @@
{
struct vm_map_entry *dead_entries;
struct vm_map *map = &vm->vm_map;
+ int flags;
UVMHIST_FUNC("uvmspace_free"); UVMHIST_CALLED(maphist);
@@ -4285,7 +4230,7 @@
*/
map->flags |= VM_MAP_DYING;
- pmap_remove_all(map->pmap);
+ flags = pmap_remove_all(map->pmap) ? UVM_FLAG_VAONLY : 0;
/* Get rid of any SYSV shared memory segments. */
if (uvm_shmexit && vm->vm_shm != NULL)
@@ -4293,7 +4238,7 @@
if (map->nentries) {
uvm_unmap_remove(map, vm_map_min(map), vm_map_max(map),
- &dead_entries, 0);
+ &dead_entries, flags);
if (dead_entries != NULL)
uvm_unmap_detach(dead_entries, 0);
}
diff -r 43c248b1ffe8 -r 622acb2ace69 sys/uvm/uvm_map.h
--- a/sys/uvm/uvm_map.h Sat Mar 14 14:05:42 2020 +0000
+++ b/sys/uvm/uvm_map.h Sat Mar 14 14:15:43 2020 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: uvm_map.h,v 1.78 2020/02/23 15:46:43 ad Exp $ */
+/* $NetBSD: uvm_map.h,v 1.79 2020/03/14 14:15:43 ad Exp $ */
/*
* Copyright (c) 1997 Charles D. Cranor and Washington University.
@@ -125,36 +125,40 @@
* a VM object (or sharing map) and offset into that object,
* and user-exported inheritance and protection information.
* Also included is control information for virtual copy operations.
+ *
+ * At runtime this is aligned on a cacheline boundary, with fields
+ * used during fault processing to do RB tree lookup clustered at
+ * the beginning.
*/
struct vm_map_entry {
struct rb_node rb_node; /* tree information */
+ vaddr_t start; /* start address */
+ vaddr_t end; /* end address */
vsize_t gap; /* free space after */
vsize_t maxgap; /* space in subtree */
struct vm_map_entry *prev; /* previous entry */
struct vm_map_entry *next; /* next entry */
- vaddr_t start; /* start address */
- vaddr_t end; /* end address */
union {
struct uvm_object *uvm_obj; /* uvm object */
struct vm_map *sub_map; /* belongs to another map */
} object; /* object I point to */
voff_t offset; /* offset into object */
- int etype; /* entry type */
+ uint8_t etype; /* entry type */
+ uint8_t flags; /* flags */
+ uint8_t advice; /* madvise advice */
+ uint8_t unused; /* unused */
vm_prot_t protection; /* protection code */
vm_prot_t max_protection; /* maximum protection */
vm_inherit_t inheritance; /* inheritance */
int wired_count; /* can be paged if == 0 */
struct vm_aref aref; /* anonymous overlay */
- int advice; /* madvise advice */
-#define uvm_map_entry_stop_copy flags
- u_int8_t flags; /* flags */
+};
+/* flags */
#define UVM_MAP_KERNEL 0x01 /* kernel map entry */
#define UVM_MAP_STATIC 0x04 /* special static entries */
#define UVM_MAP_NOMERGE 0x08 /* this entry is not mergable */
-};
-
#define VM_MAPENT_ISWIRED(entry) ((entry)->wired_count != 0)
/*
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