Author: alc
Date: Sun Aug 14 22:00:45 2016
New Revision: 304102
URL: https://svnweb.freebsd.org/changeset/base/304102
Log:
Eliminate unneeded vm_page_xbusy() and vm_page_xunbusy() operations when
neither vm_pager_has_page() nor vm_pager_get_pages() is called.
Reviewed by: kib, markj
MFC after: 3 weeks
Modified:
head/sys/kern/kern_exec.c
head/sys/kern/uipc_shm.c
head/sys/vm/vm_glue.c
Modified: head/sys/kern/kern_exec.c
==============================================================================
--- head/sys/kern/kern_exec.c Sun Aug 14 20:22:03 2016 (r304101)
+++ head/sys/kern/kern_exec.c Sun Aug 14 22:00:45 2016 (r304102)
@@ -984,8 +984,9 @@ exec_map_first_page(imgp)
#if VM_NRESERVLEVEL > 0
vm_object_color(object, 0);
#endif
- ma[0] = vm_page_grab(object, 0, VM_ALLOC_NORMAL);
+ ma[0] = vm_page_grab(object, 0, VM_ALLOC_NORMAL | VM_ALLOC_NOBUSY);
if (ma[0]->valid != VM_PAGE_BITS_ALL) {
+ vm_page_xbusy(ma[0]);
if (!vm_pager_has_page(object, 0, NULL, &after)) {
vm_page_lock(ma[0]);
vm_page_free(ma[0]);
@@ -1021,10 +1022,10 @@ exec_map_first_page(imgp)
VM_OBJECT_WUNLOCK(object);
return (EIO);
}
+ vm_page_xunbusy(ma[0]);
for (i = 1; i < initial_pagein; i++)
vm_page_readahead_finish(ma[i]);
}
- vm_page_xunbusy(ma[0]);
vm_page_lock(ma[0]);
vm_page_hold(ma[0]);
vm_page_activate(ma[0]);
Modified: head/sys/kern/uipc_shm.c
==============================================================================
--- head/sys/kern/uipc_shm.c Sun Aug 14 20:22:03 2016 (r304101)
+++ head/sys/kern/uipc_shm.c Sun Aug 14 22:00:45 2016 (r304102)
@@ -182,8 +182,9 @@ uiomove_object_page(vm_object_t obj, siz
* lock to page out tobj's pages because tobj is a OBJT_SWAP
* type object.
*/
- m = vm_page_grab(obj, idx, VM_ALLOC_NORMAL);
+ m = vm_page_grab(obj, idx, VM_ALLOC_NORMAL | VM_ALLOC_NOBUSY);
if (m->valid != VM_PAGE_BITS_ALL) {
+ vm_page_xbusy(m);
if (vm_pager_has_page(obj, idx, NULL, NULL)) {
rv = vm_pager_get_pages(obj, &m, 1, NULL, NULL);
if (rv != VM_PAGER_OK) {
@@ -198,8 +199,8 @@ uiomove_object_page(vm_object_t obj, siz
}
} else
vm_page_zero_invalid(m, TRUE);
+ vm_page_xunbusy(m);
}
- vm_page_xunbusy(m);
vm_page_lock(m);
vm_page_hold(m);
if (m->queue == PQ_NONE) {
Modified: head/sys/vm/vm_glue.c
==============================================================================
--- head/sys/vm/vm_glue.c Sun Aug 14 20:22:03 2016 (r304101)
+++ head/sys/vm/vm_glue.c Sun Aug 14 22:00:45 2016 (r304102)
@@ -236,8 +236,9 @@ vm_imgact_hold_page(vm_object_t object,
VM_OBJECT_WLOCK(object);
pindex = OFF_TO_IDX(offset);
- m = vm_page_grab(object, pindex, VM_ALLOC_NORMAL);
+ m = vm_page_grab(object, pindex, VM_ALLOC_NORMAL | VM_ALLOC_NOBUSY);
if (m->valid != VM_PAGE_BITS_ALL) {
+ vm_page_xbusy(m);
rv = vm_pager_get_pages(object, &m, 1, NULL, NULL);
if (rv != VM_PAGER_OK) {
vm_page_lock(m);
@@ -246,8 +247,8 @@ vm_imgact_hold_page(vm_object_t object,
m = NULL;
goto out;
}
+ vm_page_xunbusy(m);
}
- vm_page_xunbusy(m);
vm_page_lock(m);
vm_page_hold(m);
vm_page_activate(m);
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