git: bb1dc6cf9c36 - main - vm_page: define partial page invalidate

The branch main has been updated by dougm:

URL: https://cgit.FreeBSD.org/src/commit/?id=bb1dc6cf9c3671c82318e22825d86d54c8d672cb

commit bb1dc6cf9c3671c82318e22825d86d54c8d672cb
Author:     Doug Moore <dougm@FreeBSD.org>
AuthorDate: 2025-02-22 01:22:47 +0000
Commit:     Doug Moore <dougm@FreeBSD.org>
CommitDate: 2025-02-22 01:22:47 +0000

    vm_page: define partial page invalidate
    
    Two different functions in different files do the same thing - fill a
    partial page with zeroes. Add that functionality to vm_page.c and
    remove it elsewhere to avoid code duplication.
    
    Reviewed by:    markj, kib
    Differential Revision:  https://reviews.freebsd.org/D49096
---
 sys/fs/tmpfs/tmpfs_subr.c | 47 ++++---------------------------------------
 sys/kern/uipc_shm.c       | 47 ++++---------------------------------------
 sys/vm/vm_page.c          | 51 +++++++++++++++++++++++++++++++++++++++++++++++
 sys/vm/vm_page.h          |  2 ++
 4 files changed, 61 insertions(+), 86 deletions(-)

diff --git a/sys/fs/tmpfs/tmpfs_subr.c b/sys/fs/tmpfs/tmpfs_subr.c
index 41d1f27caf13..37be0b762579 100644
--- a/sys/fs/tmpfs/tmpfs_subr.c
+++ b/sys/fs/tmpfs/tmpfs_subr.c
@@ -493,50 +493,11 @@ static int
 tmpfs_partial_page_invalidate(vm_object_t object, vm_pindex_t idx, int base,
     int end, boolean_t ignerr)
 {
-	vm_page_t m;
-	int rv, error;
-
-	VM_OBJECT_ASSERT_WLOCKED(object);
-	KASSERT(base >= 0, ("%s: base %d", __func__, base));
-	KASSERT(end - base <= PAGE_SIZE, ("%s: base %d end %d", __func__, base,
-	    end));
-	error = 0;
-
-retry:
-	m = vm_page_grab(object, idx, VM_ALLOC_NOCREAT);
-	if (m != NULL) {
-		MPASS(vm_page_all_valid(m));
-	} else if (vm_pager_has_page(object, idx, NULL, NULL)) {
-		m = vm_page_alloc(object, idx, VM_ALLOC_NORMAL |
-		    VM_ALLOC_WAITFAIL);
-		if (m == NULL)
-			goto retry;
-		vm_object_pip_add(object, 1);
-		VM_OBJECT_WUNLOCK(object);
-		rv = vm_pager_get_pages(object, &m, 1, NULL, NULL);
-		VM_OBJECT_WLOCK(object);
-		vm_object_pip_wakeup(object);
-		if (rv == VM_PAGER_OK) {
-			/*
-			 * Since the page was not resident, and therefore not
-			 * recently accessed, immediately enqueue it for
-			 * asynchronous laundering.  The current operation is
-			 * not regarded as an access.
-			 */
-			vm_page_launder(m);
-		} else {
-			vm_page_free(m);
-			m = NULL;
-			if (!ignerr)
-				error = EIO;
-		}
-	}
-	if (m != NULL) {
-		pmap_zero_page_area(m, base, end - base);
-		vm_page_set_dirty(m);
-		vm_page_xunbusy(m);
-	}
+	int error;
 
+	error = vm_page_grab_zero_partial(object, idx, base, end);
+	if (ignerr)
+		error = 0;
 	return (error);
 }
 
diff --git a/sys/kern/uipc_shm.c b/sys/kern/uipc_shm.c
index 026611a59593..b4016e9dd6bf 100644
--- a/sys/kern/uipc_shm.c
+++ b/sys/kern/uipc_shm.c
@@ -697,51 +697,12 @@ static int
 shm_partial_page_invalidate(vm_object_t object, vm_pindex_t idx, int base,
     int end)
 {
-	vm_page_t m;
-	int rv;
+	int error;
 
-	VM_OBJECT_ASSERT_WLOCKED(object);
-	KASSERT(base >= 0, ("%s: base %d", __func__, base));
-	KASSERT(end - base <= PAGE_SIZE, ("%s: base %d end %d", __func__, base,
-	    end));
-
-retry:
-	m = vm_page_grab(object, idx, VM_ALLOC_NOCREAT);
-	if (m != NULL) {
-		MPASS(vm_page_all_valid(m));
-	} else if (vm_pager_has_page(object, idx, NULL, NULL)) {
-		m = vm_page_alloc(object, idx,
-		    VM_ALLOC_NORMAL | VM_ALLOC_WAITFAIL);
-		if (m == NULL)
-			goto retry;
-		vm_object_pip_add(object, 1);
+	error = vm_page_grab_zero_partial(object, idx, base, end);
+	if (error == EIO)
 		VM_OBJECT_WUNLOCK(object);
-		rv = vm_pager_get_pages(object, &m, 1, NULL, NULL);
-		VM_OBJECT_WLOCK(object);
-		vm_object_pip_wakeup(object);
-		if (rv == VM_PAGER_OK) {
-			/*
-			 * Since the page was not resident, and therefore not
-			 * recently accessed, immediately enqueue it for
-			 * asynchronous laundering.  The current operation is
-			 * not regarded as an access.
-			 */
-			vm_page_launder(m);
-		} else {
-			vm_page_free(m);
-			VM_OBJECT_WUNLOCK(object);
-			return (EIO);
-		}
-	}
-	if (m != NULL) {
-		pmap_zero_page_area(m, base, end - base);
-		KASSERT(vm_page_all_valid(m), ("%s: page %p is invalid",
-		    __func__, m));
-		vm_page_set_dirty(m);
-		vm_page_xunbusy(m);
-	}
-
-	return (0);
+	return (error);
 }
 
 static int
diff --git a/sys/vm/vm_page.c b/sys/vm/vm_page.c
index c105aafca40f..e4c2aadf5d56 100644
--- a/sys/vm/vm_page.c
+++ b/sys/vm/vm_page.c
@@ -5086,6 +5086,57 @@ out:
 	return (VM_PAGER_OK);
 }
 
+/*
+ * Fill a partial page with zeroes.  The object write lock is held on entry and
+ * exit, but may be temporarily released.
+ */
+int
+vm_page_grab_zero_partial(vm_object_t object, vm_pindex_t pindex, int base,
+    int end)
+{
+	vm_page_t m;
+	int rv;
+
+	VM_OBJECT_ASSERT_WLOCKED(object);
+	KASSERT(base >= 0, ("%s: base %d", __func__, base));
+	KASSERT(end - base <= PAGE_SIZE, ("%s: base %d end %d", __func__, base,
+	    end));
+
+retry:
+	m = vm_page_grab(object, pindex, VM_ALLOC_NOCREAT);
+	if (m != NULL) {
+		MPASS(vm_page_all_valid(m));
+	} else if (vm_pager_has_page(object, pindex, NULL, NULL)) {
+		m = vm_page_alloc(object, pindex,
+		    VM_ALLOC_NORMAL | VM_ALLOC_WAITFAIL);
+		if (m == NULL)
+			goto retry;
+		vm_object_pip_add(object, 1);
+		VM_OBJECT_WUNLOCK(object);
+		rv = vm_pager_get_pages(object, &m, 1, NULL, NULL);
+		VM_OBJECT_WLOCK(object);
+		vm_object_pip_wakeup(object);
+		if (rv != VM_PAGER_OK) {
+			vm_page_free(m);
+			return (EIO);
+		}
+
+		/*
+		 * Since the page was not resident, and therefore not recently
+		 * accessed, immediately enqueue it for asynchronous laundering.
+		 * The current operation is not regarded as an access.
+		 */
+		vm_page_launder(m);
+	} else
+		return (0);
+
+	pmap_zero_page_area(m, base, end - base);
+	KASSERT(vm_page_all_valid(m), ("%s: page %p is invalid", __func__, m));
+	vm_page_set_dirty(m);
+	vm_page_xunbusy(m);
+	return (0);
+}
+
 /*
  * Locklessly grab a valid page.  If the page is not valid or not yet
  * allocated this will fall back to the object lock method.
diff --git a/sys/vm/vm_page.h b/sys/vm/vm_page.h
index 744688bf789b..5a166d9ba44c 100644
--- a/sys/vm/vm_page.h
+++ b/sys/vm/vm_page.h
@@ -627,6 +627,8 @@ vm_page_t vm_page_alloc_noobj_contig_domain(int domain, int req, u_long npages,
     vm_memattr_t memattr);
 void vm_page_bits_set(vm_page_t m, vm_page_bits_t *bits, vm_page_bits_t set);
 bool vm_page_blacklist_add(vm_paddr_t pa, bool verbose);
+int vm_page_grab_zero_partial(vm_object_t object, vm_pindex_t pindex, int base,
+    int end);
 vm_page_t vm_page_grab(vm_object_t, vm_pindex_t, int);
 vm_page_t vm_page_grab_unlocked(vm_object_t, vm_pindex_t, int);
 int vm_page_grab_pages(vm_object_t object, vm_pindex_t pindex, int allocflags,