The branch main has been updated by kib:
URL:
https://cgit.FreeBSD.org/src/commit/?id=6ed68e6f5d47ca30716d4e06c1452e68530970db
commit 6ed68e6f5d47ca30716d4e06c1452e68530970db
Author: Konstantin Belousov <k...@freebsd.org>
AuthorDate: 2024-12-05 22:44:08 +0000
Commit: Konstantin Belousov <k...@freebsd.org>
CommitDate: 2024-12-09 03:27:44 +0000
vm_map: overlap system map mutex and user man sx
This saves 616-584 = 32 bytes per struct vmspace on amd64, which allows
to pack 7 vmspaces per page vs. 6 for non-overlapping layout.
I used anonymous union member feature to avoid too much churn.
Reviewed by: alc, markj
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D47934
---
sys/vm/vm_kern.c | 3 +--
sys/vm/vm_map.c | 18 +++++++++++-------
sys/vm/vm_map.h | 7 +++++--
3 files changed, 17 insertions(+), 11 deletions(-)
diff --git a/sys/vm/vm_kern.c b/sys/vm/vm_kern.c
index a748a6c57d65..29a64a0fe6d8 100644
--- a/sys/vm/vm_kern.c
+++ b/sys/vm/vm_kern.c
@@ -830,8 +830,7 @@ kmem_init(vm_offset_t start, vm_offset_t end)
vm_size_t quantum;
int domain;
- vm_map_init(kernel_map, kernel_pmap, VM_MIN_KERNEL_ADDRESS, end);
- kernel_map->system_map = 1;
+ vm_map_init_system(kernel_map, kernel_pmap, VM_MIN_KERNEL_ADDRESS, end);
vm_map_lock(kernel_map);
/* N.B.: cannot use kgdb to debug, starting with this assignment ... */
(void)vm_map_insert(kernel_map, NULL, 0,
diff --git a/sys/vm/vm_map.c b/sys/vm/vm_map.c
index 910ebfb6dc4e..c3aa499e0dc7 100644
--- a/sys/vm/vm_map.c
+++ b/sys/vm/vm_map.c
@@ -292,9 +292,7 @@ vmspace_zinit(void *mem, int size, int flags)
vm = (struct vmspace *)mem;
map = &vm->vm_map;
- memset(map, 0, sizeof(*map));
- mtx_init(&map->system_mtx, "vm map (system)", NULL,
- MTX_DEF | MTX_DUPOK);
+ memset(map, 0, sizeof(*map)); /* set map->system_map = false */
sx_init(&map->lock, "vm map (user)");
PMAP_LOCK_INIT(vmspace_pmap(vm));
return (0);
@@ -890,7 +888,6 @@ _vm_map_init(vm_map_t map, pmap_t pmap, vm_offset_t min,
vm_offset_t max)
map->header.eflags = MAP_ENTRY_HEADER;
map->needs_wakeup = FALSE;
- map->system_map = 0;
map->pmap = pmap;
map->header.end = min;
map->header.start = max;
@@ -908,13 +905,20 @@ _vm_map_init(vm_map_t map, pmap_t pmap, vm_offset_t min,
vm_offset_t max)
void
vm_map_init(vm_map_t map, pmap_t pmap, vm_offset_t min, vm_offset_t max)
{
-
_vm_map_init(map, pmap, min, max);
- mtx_init(&map->system_mtx, "vm map (system)", NULL,
- MTX_DEF | MTX_DUPOK);
+ map->system_map = false;
sx_init(&map->lock, "vm map (user)");
}
+void
+vm_map_init_system(vm_map_t map, pmap_t pmap, vm_offset_t min, vm_offset_t max)
+{
+ _vm_map_init(map, pmap, min, max);
+ map->system_map = true;
+ mtx_init(&map->system_mtx, "vm map (system)", NULL, MTX_DEF |
+ MTX_DUPOK);
+}
+
/*
* vm_map_entry_dispose: [ internal use only ]
*
diff --git a/sys/vm/vm_map.h b/sys/vm/vm_map.h
index d0b4bb52968e..5ecec0531e1c 100644
--- a/sys/vm/vm_map.h
+++ b/sys/vm/vm_map.h
@@ -203,8 +203,10 @@ vm_map_entry_system_wired_count(vm_map_entry_t entry)
*/
struct vm_map {
struct vm_map_entry header; /* List of entries */
- struct sx lock; /* Lock for map data */
- struct mtx system_mtx;
+ union {
+ struct sx lock; /* Lock for map data */
+ struct mtx system_mtx;
+ };
int nentries; /* Number of entries */
vm_size_t size; /* virtual size */
u_int timestamp; /* Version number */
@@ -484,6 +486,7 @@ int vm_map_fixed(vm_map_t, vm_object_t, vm_ooffset_t,
vm_offset_t, vm_size_t,
vm_offset_t vm_map_findspace(vm_map_t, vm_offset_t, vm_size_t);
int vm_map_inherit (vm_map_t, vm_offset_t, vm_offset_t, vm_inherit_t);
void vm_map_init(vm_map_t, pmap_t, vm_offset_t, vm_offset_t);
+void vm_map_init_system(vm_map_t, pmap_t, vm_offset_t, vm_offset_t);
int vm_map_insert (vm_map_t, vm_object_t, vm_ooffset_t, vm_offset_t,
vm_offset_t, vm_prot_t, vm_prot_t, int);
int vm_map_lookup (vm_map_t *, vm_offset_t, vm_prot_t, vm_map_entry_t *,
vm_object_t *,
vm_pindex_t *, vm_prot_t *, boolean_t *);
