Author: raj
Date: Mon Aug 19 15:58:39 2013
New Revision: 254535
URL: http://svnweb.freebsd.org/changeset/base/254535
Log:
Simplify and clean up pmap_clearbit()
There is no need for calling vm_page_dirty() when clearing "modified" flag as
it is already set for that page in pmap_fault_fixup() or pmap_enter() thanks
to "modified" bit emulation.
Also, there is no need for checking PTE "referenced" or "writeable" flags. If
there is a request to clear a particular flag we should just do it.
Submitted by: Zbigniew Bodek <z...@semihalf.com>
Reviewed by: gber
Sponsored by: The FreeBSD Foundation, Semihalf
Modified:
head/sys/arm/arm/pmap-v6.c
Modified: head/sys/arm/arm/pmap-v6.c
==============================================================================
--- head/sys/arm/arm/pmap-v6.c Mon Aug 19 15:51:30 2013 (r254534)
+++ head/sys/arm/arm/pmap-v6.c Mon Aug 19 15:58:39 2013 (r254535)
@@ -900,9 +900,6 @@ pmap_clearbit(struct vm_page *m, u_int m
rw_wlock(&pvh_global_lock);
- if (maskbits & PVF_WRITE)
- maskbits |= PVF_MOD;
-
if (TAILQ_EMPTY(&m->md.pv_list)) {
rw_wunlock(&pvh_global_lock);
return (0);
@@ -924,14 +921,12 @@ pmap_clearbit(struct vm_page *m, u_int m
ptep = &l2b->l2b_kva[l2pte_index(va)];
npte = opte = *ptep;
- if ((maskbits & (PVF_WRITE|PVF_MOD)) && L2_S_WRITABLE(opte)) {
- vm_page_dirty(m);
-
+ if (maskbits & (PVF_WRITE | PVF_MOD)) {
/* make the pte read only */
npte |= L2_APX;
}
- if ((maskbits & PVF_REF) && L2_S_REFERENCED(opte)) {
+ if (maskbits & PVF_REF) {
/*
* Clear referenced flag in PTE so that we
* will take a flag fault the next time the mapping
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