Author: alc
Date: Thu Sep 6 16:26:04 2012
New Revision: 240166
URL: http://svn.freebsd.org/changeset/base/240166
Log:
There is no need to release the pvh global lock around calls to
pmap_get_pv_entry(). In fact, some callers already held it around calls.
(In earlier versions, the same statements would apply to the page queues
lock.)
While I'm here tidy up the style of a few nearby statements and revise
some comments.
Tested by: Ian Lepore
Modified:
head/sys/arm/arm/pmap.c
Modified: head/sys/arm/arm/pmap.c
==============================================================================
--- head/sys/arm/arm/pmap.c Thu Sep 6 14:59:53 2012 (r240165)
+++ head/sys/arm/arm/pmap.c Thu Sep 6 16:26:04 2012 (r240166)
@@ -1584,13 +1584,13 @@ pmap_clearbit(struct vm_page *pg, u_int
* pmap_remove_pv: remove a mappiing from a vm_page list
*
* NOTE: pmap_enter_pv expects to lock the pvh itself
- * pmap_remove_pv expects te caller to lock the pvh before calling
+ * pmap_remove_pv expects the caller to lock the pvh before calling
*/
/*
* pmap_enter_pv: enter a mapping onto a vm_page lst
*
- * => caller should hold the proper lock on pmap_main_lock
+ * => caller should hold the proper lock on pvh_global_lock
* => caller should have pmap locked
* => we will gain the lock on the vm_page and allocate the new pv_entry
* => caller should adjust ptp's wire_count before calling
@@ -1600,12 +1600,11 @@ static void
pmap_enter_pv(struct vm_page *pg, struct pv_entry *pve, pmap_t pm,
vm_offset_t va, u_int flags)
{
-
int km;
rw_assert(&pvh_global_lock, RA_WLOCKED);
- if (pg->md.pv_kva) {
+ if (pg->md.pv_kva != 0) {
/* PMAP_ASSERT_LOCKED(pmap_kernel()); */
pve->pv_pmap = pmap_kernel();
pve->pv_va = pg->md.pv_kva;
@@ -1617,10 +1616,8 @@ pmap_enter_pv(struct vm_page *pg, struct
TAILQ_INSERT_HEAD(&pg->md.pv_list, pve, pv_list);
TAILQ_INSERT_HEAD(&pve->pv_pmap->pm_pvlist, pve, pv_plist);
PMAP_UNLOCK(pmap_kernel());
- rw_wunlock(&pvh_global_lock);
if ((pve = pmap_get_pv_entry()) == NULL)
- panic("pmap_kenter_internal: no pv entries");
- rw_wlock(&pvh_global_lock);
+ panic("pmap_kenter_pv: no pv entries");
if (km)
PMAP_LOCK(pmap_kernel());
}
@@ -2824,22 +2821,20 @@ pmap_kenter_internal(vm_offset_t va, vm_
*pte |= L2_S_PROT_U;
PTE_SYNC(pte);
- /* kernel direct mappings can be shared, so use a pv_entry
- * to ensure proper caching.
- *
- * The pvzone is used to delay the recording of kernel
- * mappings until the VM is running.
- *
- * This expects the physical memory to have vm_page_array entry.
- */
- if (pvzone != NULL && (m = vm_phys_paddr_to_vm_page(pa))) {
+ /*
+ * A kernel mapping may not be the page's only mapping, so create a PV
+ * entry to ensure proper caching.
+ *
+ * The existence test for the pvzone is used to delay the recording of
+ * kernel mappings until the VM system is fully initialized.
+ *
+ * This expects the physical memory to have a vm_page_array entry.
+ */
+ if (pvzone != NULL && (m = vm_phys_paddr_to_vm_page(pa)) != NULL) {
rw_wlock(&pvh_global_lock);
- if (!TAILQ_EMPTY(&m->md.pv_list) || m->md.pv_kva) {
- /* release vm_page lock for pv_entry UMA */
- rw_wunlock(&pvh_global_lock);
+ if (!TAILQ_EMPTY(&m->md.pv_list) || m->md.pv_kva != 0) {
if ((pve = pmap_get_pv_entry()) == NULL)
panic("pmap_kenter_internal: no pv entries");
- rw_wlock(&pvh_global_lock);
PMAP_LOCK(pmap_kernel());
pmap_enter_pv(m, pve, pmap_kernel(), va,
PVF_WRITE | PVF_UNMAN);
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