Author: alc
Date: Sun Aug 5 16:59:02 2012
New Revision: 239072
URL: http://svn.freebsd.org/changeset/base/239072
Log:
Shave off a few more cycles from the average execution time of pmap_enter()
by simplifying the control flow and reducing the live range of "om".
Modified:
head/sys/amd64/amd64/pmap.c
Modified: head/sys/amd64/amd64/pmap.c
==============================================================================
--- head/sys/amd64/amd64/pmap.c Sun Aug 5 15:55:36 2012 (r239071)
+++ head/sys/amd64/amd64/pmap.c Sun Aug 5 16:59:02 2012 (r239072)
@@ -3468,7 +3468,7 @@ pmap_enter(pmap_t pmap, vm_offset_t va,
newpte |= PG_G;
newpte |= pmap_cache_bits(m->md.pat_mode, 0);
- mpte = om = NULL;
+ mpte = NULL;
lock = NULL;
rw_rlock(&pvh_global_lock);
@@ -3540,12 +3540,6 @@ retry:
if (((origpte ^ newpte) & ~(PG_M | PG_A)) == 0)
goto unchanged;
goto validate;
- } else {
- /*
- * Yes, fall through to validate the new mapping.
- */
- if ((origpte & PG_MANAGED) != 0)
- om = PHYS_TO_VM_PAGE(opa);
}
} else {
/*
@@ -3578,6 +3572,7 @@ validate:
opa = origpte & PG_FRAME;
if (opa != pa) {
if ((origpte & PG_MANAGED) != 0) {
+ om = PHYS_TO_VM_PAGE(opa);
if ((origpte & (PG_M | PG_RW)) == (PG_M |
PG_RW))
vm_page_dirty(om);
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