svn commit: r208687 - head/sys/sun4v/sun4v
Alan Cox
alc at FreeBSD.org
Tue Jun 1 05:19:28 UTC 2010
Author: alc
Date: Tue Jun 1 05:18:48 2010
New Revision: 208687
URL: http://svn.freebsd.org/changeset/base/208687
Log:
Merge portions of r208645 and supporting code from the i386 pmap:
When I pushed down the page queues lock into pmap_is_modified(), I created
an ordering dependence: A pmap operation that clears PG_WRITEABLE and calls
vm_page_dirty() must perform the call first. Otherwise, pmap_is_modified()
could return FALSE without acquiring the page queues lock because the page
is not (currently) writeable, and the caller to pmap_is_modified() might
believe that the page's dirty field is clear because it has not seen the
effect of the vm_page_dirty() call.
When I pushed down the page queues lock into pmap_is_modified(), I
overlooked one place where this ordering dependence is violated:
pmap_enter(). In a rare situation pmap_enter() can be called to replace a
dirty mapping to one page with a mapping to another page. (I say rare
because replacements generally occur as a result of a copy-on-write fault,
and so the old page is not dirty.) This change delays clearing PG_WRITEABLE
until after vm_page_dirty() has been called.
Fixing the ordering dependency also makes it easy to introduce a small
optimization: When pmap_enter() used to replace a mapping to one page with a
mapping to another page, it freed the pv entry for the first mapping and
later called the pv entry allocator for the new mapping. Now, pmap_enter()
attempts to recycle the old pv entry, saving two calls to the pv entry
allocator.
There is no point in setting PG_WRITEABLE on unmanaged pages, so don't.
Modified:
head/sys/sun4v/sun4v/pmap.c
Modified: head/sys/sun4v/sun4v/pmap.c
==============================================================================
--- head/sys/sun4v/sun4v/pmap.c Tue Jun 1 04:38:05 2010 (r208686)
+++ head/sys/sun4v/sun4v/pmap.c Tue Jun 1 05:18:48 2010 (r208687)
@@ -189,6 +189,9 @@ if (pmap_debug) printf
static void free_pv_entry(pv_entry_t pv);
static pv_entry_t get_pv_entry(pmap_t locked_pmap);
+static void pmap_pvh_free(struct md_page *pvh, pmap_t pmap, vm_offset_t va);
+static pv_entry_t pmap_pvh_remove(struct md_page *pvh, pmap_t pmap,
+ vm_offset_t va);
static void pmap_insert_entry(pmap_t pmap, vm_offset_t va, vm_page_t m);
static void pmap_remove_entry(struct pmap *pmap, vm_page_t m, vm_offset_t va);
@@ -1077,6 +1080,7 @@ pmap_enter(pmap_t pmap, vm_offset_t va,
{
vm_paddr_t pa, opa;
uint64_t tte_data, otte_data;
+ pv_entry_t pv;
vm_page_t om;
int invlva;
@@ -1103,6 +1107,7 @@ pmap_enter(pmap_t pmap, vm_offset_t va,
pmap_add_tte(pmap, va, m, &tte_data, wired);
} else if (pa != opa) {
+ pv = NULL;
/*
* Mapping has changed, handle validating new mapping.
*
@@ -1112,10 +1117,23 @@ pmap_enter(pmap_t pmap, vm_offset_t va,
if (otte_data & VTD_MANAGED) {
om = PHYS_TO_VM_PAGE(opa);
- pmap_remove_entry(pmap, om, va);
+ pv = pmap_pvh_remove(&om->md, pmap, va);
}
- pmap_add_tte(pmap, va, m, &tte_data, wired);
+ if (wired)
+ pmap->pm_stats.wired_count++;
+
+ if ((m->flags & (PG_FICTITIOUS | PG_UNMANAGED)) == 0) {
+ if (pv == NULL)
+ pv = get_pv_entry(pmap);
+ pv->pv_va = va;
+ pv->pv_pmap = pmap;
+ TAILQ_INSERT_TAIL(&pmap->pm_pvlist, pv, pv_plist);
+ TAILQ_INSERT_TAIL(&m->md.pv_list, pv, pv_list);
+ m->md.pv_list_count++;
+ tte_data |= VTD_MANAGED;
+ } else if (pv != NULL)
+ free_pv_entry(pv);
} else /* (pa == opa) */ {
/*
@@ -1144,7 +1162,8 @@ pmap_enter(pmap_t pmap, vm_offset_t va,
*/
if ((prot & VM_PROT_WRITE) != 0) {
tte_data |= VTD_SW_W;
- vm_page_flag_set(m, PG_WRITEABLE);
+ if ((tte_data & VTD_MANAGED) != 0)
+ vm_page_flag_set(m, PG_WRITEABLE);
}
if ((prot & VM_PROT_EXECUTE) != 0)
tte_data |= VTD_X;
@@ -1168,6 +1187,9 @@ pmap_enter(pmap_t pmap, vm_offset_t va,
if ((pa & VTD_SW_W) != 0)
invlva = TRUE;
}
+ if ((otte_data & VTD_MANAGED) != 0 &&
+ TAILQ_EMPTY(&om->md.pv_list))
+ vm_page_flag_clear(om, PG_WRITEABLE);
if (invlva)
pmap_invalidate_page(pmap, va, TRUE);
}
@@ -2047,16 +2069,17 @@ pmap_remove_all(vm_page_t m)
vm_page_unlock_queues();
}
-static void
-pmap_remove_entry(pmap_t pmap, vm_page_t m, vm_offset_t va)
+static pv_entry_t
+pmap_pvh_remove(struct md_page *pvh, pmap_t pmap, vm_offset_t va)
{
pv_entry_t pv;
if (pmap != kernel_pmap)
- DPRINTF("pmap_remove_entry(va=0x%lx, pa=0x%lx)\n", va, VM_PAGE_TO_PHYS(m));
+ DPRINTF("pmap_pvh_remove(va=0x%lx, pa=0x%lx)\n", va,
+ VM_PAGE_TO_PHYS(member2struct(vm_page, md, pvh)));
PMAP_LOCK_ASSERT(pmap, MA_OWNED);
mtx_assert(&vm_page_queue_mtx, MA_OWNED);
- if (m->md.pv_list_count < pmap->pm_stats.resident_count) {
- TAILQ_FOREACH(pv, &m->md.pv_list, pv_list) {
+ if (pvh->pv_list_count < pmap->pm_stats.resident_count) {
+ TAILQ_FOREACH(pv, &pvh->pv_list, pv_list) {
if (pmap == pv->pv_pmap && va == pv->pv_va)
break;
}
@@ -2066,13 +2089,33 @@ pmap_remove_entry(pmap_t pmap, vm_page_t
break;
}
}
- KASSERT(pv != NULL, ("pmap_remove_entry: pv not found va=0x%lx pa=0x%lx", va, VM_PAGE_TO_PHYS(m)));
- TAILQ_REMOVE(&m->md.pv_list, pv, pv_list);
- m->md.pv_list_count--;
+ if (pv != NULL) {
+ TAILQ_REMOVE(&pvh->pv_list, pv, pv_list);
+ pvh->pv_list_count--;
+ TAILQ_REMOVE(&pmap->pm_pvlist, pv, pv_plist);
+ }
+ return (pv);
+}
+
+static void
+pmap_pvh_free(struct md_page *pvh, pmap_t pmap, vm_offset_t va)
+{
+ pv_entry_t pv;
+
+ pv = pmap_pvh_remove(pvh, pmap, va);
+ KASSERT(pv != NULL, ("pmap_pvh_free: pv not found va=0x%lx pa=0x%lx",
+ va, VM_PAGE_TO_PHYS(member2struct(vm_page, md, pvh))));
+ free_pv_entry(pv);
+}
+
+static void
+pmap_remove_entry(pmap_t pmap, vm_page_t m, vm_offset_t va)
+{
+
+ mtx_assert(&vm_page_queue_mtx, MA_OWNED);
+ pmap_pvh_free(&m->md, pmap, va);
if (TAILQ_EMPTY(&m->md.pv_list))
vm_page_flag_clear(m, PG_WRITEABLE);
- TAILQ_REMOVE(&pmap->pm_pvlist, pv, pv_plist);
- free_pv_entry(pv);
}
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