d/freebsd-dev
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Micro-optimize kmem_unback().

Browse Source 
We can remove some unnecessary object radix tree lookups by using the
object memq to iterate over pages in the specified range. This does not,
however, eliminate the lookup needed in vm_page_free_toq() to remove each
tree entry.

Reviewed by:	alc, kib (previous revision)
MFC after:	1 week
Differential Revision:	https://reviews.freebsd.org/D11945
This commit is contained in:
Mark Johnston 2017-08-11 03:09:11 +00:00
parent ee51cfe17c
commit 7e05ffa6e6
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=322391
1 changed files with 6 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
sys/vm/vm_kern.c
View File

@ -386,17 +386,19 @@ kmem_back(vm_object_t object, vm_offset_t addr, vm_size_t size, int flags)
void
kmem_unback(vm_object_t object, vm_offset_t addr, vm_size_t size)
{
vm_page_t m;
vm_offset_t i, offset;
vm_page_t m, next;
vm_offset_t end, offset;
KASSERT(object == kmem_object || object == kernel_object,
("kmem_unback: only supports kernel objects."));
pmap_remove(kernel_pmap, addr, addr + size);
offset = addr - VM_MIN_KERNEL_ADDRESS;
end = offset + size;
VM_OBJECT_WLOCK(object);
for (i = 0; i < size; i += PAGE_SIZE) {
m = vm_page_lookup(object, atop(offset + i));
for (m = vm_page_lookup(object, atop(offset)); offset < end;
offset += PAGE_SIZE, m = next) {
next = vm_page_next(m);
vm_page_unwire(m, PQ_NONE);
vm_page_free(m);
}