svn commit: r349432 - in head/sys: amd64/sgx dev/drm2/ttm vm
Mark Johnston
markj at FreeBSD.org
Wed Jun 26 17:37:53 UTC 2019
Author: markj
Date: Wed Jun 26 17:37:51 2019
New Revision: 349432
URL: https://svnweb.freebsd.org/changeset/base/349432
Log:
Add a return value to vm_page_remove().
Use it to indicate whether the page may be safely freed following
its removal from the object. Also change vm_page_remove() to assume
that the page's object pointer is non-NULL, and have callers perform
this check instead.
This is a step towards an implementation of an atomic reference counter
for each physical page structure.
Reviewed by: alc, dougm, kib
MFC after: 1 week
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D20758
Modified:
head/sys/amd64/sgx/sgx.c
head/sys/dev/drm2/ttm/ttm_bo_vm.c
head/sys/vm/device_pager.c
head/sys/vm/vm_fault.c
head/sys/vm/vm_object.c
head/sys/vm/vm_page.c
head/sys/vm/vm_page.h
Modified: head/sys/amd64/sgx/sgx.c
==============================================================================
--- head/sys/amd64/sgx/sgx.c Wed Jun 26 17:32:31 2019 (r349431)
+++ head/sys/amd64/sgx/sgx.c Wed Jun 26 17:37:51 2019 (r349432)
@@ -358,7 +358,7 @@ sgx_page_remove(struct sgx_softc *sc, vm_page_t p)
uint64_t offs;
vm_page_lock(p);
- vm_page_remove(p);
+ (void)vm_page_remove(p);
vm_page_unlock(p);
dprintf("%s: p->pidx %ld\n", __func__, p->pindex);
Modified: head/sys/dev/drm2/ttm/ttm_bo_vm.c
==============================================================================
--- head/sys/dev/drm2/ttm/ttm_bo_vm.c Wed Jun 26 17:32:31 2019 (r349431)
+++ head/sys/dev/drm2/ttm/ttm_bo_vm.c Wed Jun 26 17:37:51 2019 (r349432)
@@ -115,7 +115,7 @@ ttm_bo_vm_fault(vm_object_t vm_obj, vm_ooffset_t offse
vm_object_pip_add(vm_obj, 1);
if (*mres != NULL) {
vm_page_lock(*mres);
- vm_page_remove(*mres);
+ (void)vm_page_remove(*mres);
vm_page_unlock(*mres);
}
retry:
Modified: head/sys/vm/device_pager.c
==============================================================================
--- head/sys/vm/device_pager.c Wed Jun 26 17:32:31 2019 (r349431)
+++ head/sys/vm/device_pager.c Wed Jun 26 17:37:51 2019 (r349432)
@@ -236,7 +236,7 @@ cdev_pager_free_page(vm_object_t object, vm_page_t m)
KASSERT((m->oflags & VPO_UNMANAGED) == 0, ("unmanaged %p", m));
pmap_remove_all(m);
vm_page_lock(m);
- vm_page_remove(m);
+ (void)vm_page_remove(m);
vm_page_unlock(m);
} else if (object->type == OBJT_DEVICE)
dev_pager_free_page(object, m);
Modified: head/sys/vm/vm_fault.c
==============================================================================
--- head/sys/vm/vm_fault.c Wed Jun 26 17:32:31 2019 (r349431)
+++ head/sys/vm/vm_fault.c Wed Jun 26 17:37:51 2019 (r349432)
@@ -1144,7 +1144,7 @@ readrest:
fs.object == fs.first_object->backing_object) {
vm_page_lock(fs.m);
vm_page_dequeue(fs.m);
- vm_page_remove(fs.m);
+ (void)vm_page_remove(fs.m);
vm_page_unlock(fs.m);
vm_page_lock(fs.first_m);
vm_page_replace_checked(fs.m, fs.first_object,
Modified: head/sys/vm/vm_object.c
==============================================================================
--- head/sys/vm/vm_object.c Wed Jun 26 17:32:31 2019 (r349431)
+++ head/sys/vm/vm_object.c Wed Jun 26 17:37:51 2019 (r349432)
@@ -1595,10 +1595,8 @@ vm_object_collapse_scan(vm_object_t object, int op)
vm_page_lock(p);
KASSERT(!pmap_page_is_mapped(p),
("freeing mapped page %p", p));
- if (!vm_page_wired(p))
+ if (vm_page_remove(p))
vm_page_free(p);
- else
- vm_page_remove(p);
vm_page_unlock(p);
continue;
}
@@ -1639,10 +1637,8 @@ vm_object_collapse_scan(vm_object_t object, int op)
vm_page_lock(p);
KASSERT(!pmap_page_is_mapped(p),
("freeing mapped page %p", p));
- if (!vm_page_wired(p))
+ if (vm_page_remove(p))
vm_page_free(p);
- else
- vm_page_remove(p);
vm_page_unlock(p);
continue;
}
Modified: head/sys/vm/vm_page.c
==============================================================================
--- head/sys/vm/vm_page.c Wed Jun 26 17:32:31 2019 (r349431)
+++ head/sys/vm/vm_page.c Wed Jun 26 17:37:51 2019 (r349432)
@@ -1458,20 +1458,21 @@ vm_page_insert_radixdone(vm_page_t m, vm_object_t obje
* vm_page_remove:
*
* Removes the specified page from its containing object, but does not
- * invalidate any backing storage.
+ * invalidate any backing storage. Return true if the page may be safely
+ * freed and false otherwise.
*
* The object must be locked. The page must be locked if it is managed.
*/
-void
+bool
vm_page_remove(vm_page_t m)
{
vm_object_t object;
vm_page_t mrem;
+ object = m->object;
+
if ((m->oflags & VPO_UNMANAGED) == 0)
vm_page_assert_locked(m);
- if ((object = m->object) == NULL)
- return;
VM_OBJECT_ASSERT_WLOCKED(object);
if (vm_page_xbusied(m))
vm_page_xunbusy_maybelocked(m);
@@ -1495,6 +1496,7 @@ vm_page_remove(vm_page_t m)
vdrop(object->handle);
m->object = NULL;
+ return (!vm_page_wired(m));
}
/*
@@ -1665,7 +1667,7 @@ vm_page_rename(vm_page_t m, vm_object_t new_object, vm
*/
m->pindex = opidx;
vm_page_lock(m);
- vm_page_remove(m);
+ (void)vm_page_remove(m);
/* Return back to the new pindex to complete vm_page_insert(). */
m->pindex = new_pindex;
@@ -3436,7 +3438,8 @@ vm_page_free_prep(vm_page_t m)
if (vm_page_sbusied(m))
panic("vm_page_free_prep: freeing busy page %p", m);
- vm_page_remove(m);
+ if (m->object != NULL)
+ (void)vm_page_remove(m);
/*
* If fictitious remove object association and
Modified: head/sys/vm/vm_page.h
==============================================================================
--- head/sys/vm/vm_page.h Wed Jun 26 17:32:31 2019 (r349431)
+++ head/sys/vm/vm_page.h Wed Jun 26 17:37:51 2019 (r349432)
@@ -561,7 +561,7 @@ bool vm_page_reclaim_contig(int req, u_long npages, vm
bool vm_page_reclaim_contig_domain(int domain, int req, u_long npages,
vm_paddr_t low, vm_paddr_t high, u_long alignment, vm_paddr_t boundary);
void vm_page_reference(vm_page_t m);
-void vm_page_remove (vm_page_t);
+bool vm_page_remove(vm_page_t);
int vm_page_rename (vm_page_t, vm_object_t, vm_pindex_t);
vm_page_t vm_page_replace(vm_page_t mnew, vm_object_t object,
vm_pindex_t pindex);
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