Date: Tue, 16 Jun 2015 00:29:31 +0300 From: Gleb Smirnoff <glebius@FreeBSD.org> To: Alan Cox <alc@rice.edu>, Konstantin Belousov <kostikbel@gmail.com> Cc: arch@FreeBSD.org Subject: Step 2 Was: more strict KPI for vm_pager_get_pages() Message-ID: <20150615212931.GG73119@glebius.int.ru>
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Hi!
This is step 2 of the "more strict pager KPI" patch:
o Uninline vm_pager_get_pages() into vm_pager.c.
o Keep all KASSERTs that enforce the KPI of pagers and of their
consumers in one place: vm_pager_get_pages().
o Keep the code that zeroes out partially valid pages in one
place in vm_pager_get_pages().
--
Totus tuus, Glebius.
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Content-Disposition: attachment; filename="pagers.step.2.diff"
Index: sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c
===================================================================
--- sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c (revision 284409)
+++ sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c (working copy)
@@ -5734,8 +5734,6 @@ zfs_getpages(struct vnode *vp, vm_page_t *m, int c
object = mreq->object;
error = 0;
- KASSERT(vp->v_object == object, ("mismatching object"));
-
if (pcount > 1 && zp->z_blksz > PAGESIZE) {
startoff = rounddown(IDX_TO_OFF(mreq->pindex), zp->z_blksz);
reqstart = OFF_TO_IDX(round_page(startoff));
@@ -5771,14 +5769,6 @@ zfs_getpages(struct vnode *vp, vm_page_t *m, int c
vm_page_unlock(m[i]);
}
- if (mreq->valid && reqsize == 1) {
- if (mreq->valid != VM_PAGE_BITS_ALL)
- vm_page_zero_invalid(mreq, TRUE);
- zfs_vmobject_wunlock(object);
- ZFS_EXIT(zfsvfs);
- return (zfs_vm_pagerret_ok);
- }
-
PCPU_INC(cnt.v_vnodein);
PCPU_ADD(cnt.v_vnodepgsin, reqsize);
Index: sys/fs/fuse/fuse_vnops.c
===================================================================
--- sys/fs/fuse/fuse_vnops.c (revision 284409)
+++ sys/fs/fuse/fuse_vnops.c (working copy)
@@ -1761,29 +1761,6 @@ fuse_vnop_getpages(struct vop_getpages_args *ap)
npages = btoc(count);
/*
- * If the requested page is partially valid, just return it and
- * allow the pager to zero-out the blanks. Partially valid pages
- * can only occur at the file EOF.
- */
-
- VM_OBJECT_WLOCK(vp->v_object);
- fuse_vm_page_lock_queues();
- if (pages[ap->a_reqpage]->valid != 0) {
- for (i = 0; i < npages; ++i) {
- if (i != ap->a_reqpage) {
- fuse_vm_page_lock(pages[i]);
- vm_page_free(pages[i]);
- fuse_vm_page_unlock(pages[i]);
- }
- }
- fuse_vm_page_unlock_queues();
- VM_OBJECT_WUNLOCK(vp->v_object);
- return 0;
- }
- fuse_vm_page_unlock_queues();
- VM_OBJECT_WUNLOCK(vp->v_object);
-
- /*
* We use only the kva address for the buffer, but this is extremely
* convienient and fast.
*/
Index: sys/fs/nfsclient/nfs_clbio.c
===================================================================
--- sys/fs/nfsclient/nfs_clbio.c (revision 284409)
+++ sys/fs/nfsclient/nfs_clbio.c (working copy)
@@ -129,23 +129,6 @@ ncl_getpages(struct vop_getpages_args *ap)
npages = btoc(count);
/*
- * Since the caller has busied the requested page, that page's valid
- * field will not be changed by other threads.
- */
- vm_page_assert_xbusied(pages[ap->a_reqpage]);
-
- /*
- * If the requested page is partially valid, just return it and
- * allow the pager to zero-out the blanks. Partially valid pages
- * can only occur at the file EOF.
- */
- if (pages[ap->a_reqpage]->valid != 0) {
- vm_pager_free_nonreq(object, pages, ap->a_reqpage, npages,
- FALSE);
- return (VM_PAGER_OK);
- }
-
- /*
* We use only the kva address for the buffer, but this is extremely
* convienient and fast.
*/
Index: sys/fs/smbfs/smbfs_io.c
===================================================================
--- sys/fs/smbfs/smbfs_io.c (revision 284409)
+++ sys/fs/smbfs/smbfs_io.c (working copy)
@@ -436,7 +436,7 @@ smbfs_getpages(ap)
struct smbnode *np;
struct smb_cred *scred;
vm_object_t object;
- vm_page_t *pages, m;
+ vm_page_t *pages;
vp = ap->a_vp;
if ((object = vp->v_object) == NULL) {
@@ -453,27 +453,6 @@ smbfs_getpages(ap)
npages = btoc(count);
reqpage = ap->a_reqpage;
- /*
- * If the requested page is partially valid, just return it and
- * allow the pager to zero-out the blanks. Partially valid pages
- * can only occur at the file EOF.
- */
- m = pages[reqpage];
-
- VM_OBJECT_WLOCK(object);
- if (m->valid != 0) {
- for (i = 0; i < npages; ++i) {
- if (i != reqpage) {
- vm_page_lock(pages[i]);
- vm_page_free(pages[i]);
- vm_page_unlock(pages[i]);
- }
- }
- VM_OBJECT_WUNLOCK(object);
- return 0;
- }
- VM_OBJECT_WUNLOCK(object);
-
scred = smbfs_malloc_scred();
smb_makescred(scred, td, cred);
Index: sys/vm/swap_pager.c
===================================================================
--- sys/vm/swap_pager.c (revision 284409)
+++ sys/vm/swap_pager.c (working copy)
@@ -1118,10 +1118,6 @@ swap_pager_getpages(vm_object_t object, vm_page_t
mreq = m[reqpage];
- KASSERT(mreq->object == object,
- ("swap_pager_getpages: object mismatch %p/%p",
- object, mreq->object));
-
/*
* Calculate range to retrieve. The pages have already been assigned
* their swapblks. We require a *contiguous* range but we know it to
Index: sys/vm/vm_pager.c
===================================================================
--- sys/vm/vm_pager.c (revision 284409)
+++ sys/vm/vm_pager.c (working copy)
@@ -251,7 +251,90 @@ vm_pager_deallocate(object)
}
/*
- * vm_pager_get_pages() - inline, see vm/vm_pager.h
+ * Retrieve pages from the VM system in order to map them into an object
+ * ( or into VM space somewhere ). If the pagein was successful, we
+ * must fully validate it.
+ */
+int
+vm_pager_get_pages(vm_object_t object, vm_page_t *m, int count, int reqpage)
+{
+ int r;
+
+ VM_OBJECT_ASSERT_WLOCKED(object);
+ KASSERT(count > 0, ("%s: 0 count", __func__));
+
+ /*
+ * If the request page is partially valid, just return it and zero-out
+ * the blanks. Partially valid pages can only occur at the file EOF.
+ */
+ if (m[reqpage]->valid != 0) {
+ vm_page_zero_invalid(m[reqpage], TRUE);
+ vm_pager_free_nonreq(object, m, reqpage, count, TRUE);
+ return (VM_PAGER_OK);
+ }
+
+#ifdef INVARIANTS
+ /*
+ * All pages must be busied, not mapped, not valid, not dirty
+ * and belong to the proper object.
+ */
+ for (int i = 0 ; i < count; i++) {
+ vm_page_assert_xbusied(m[i]);
+ KASSERT(!pmap_page_is_mapped(m[i]),
+ ("%s: page %p is mapped", __func__, m[i]));
+ KASSERT(m[i]->valid == 0,
+ ("%s: request for a valid page %p", __func__, m[i]));
+ KASSERT(m[i]->dirty == 0,
+ ("%s: page %p is dirty", __func__, m[i]));
+ KASSERT(m[i]->object == object,
+ ("%s: wrong object %p/%p", __func__, object, m[i]->object));
+ }
+#endif
+
+ r = (*pagertab[object->type]->pgo_getpages)(object, m, count, reqpage);
+ if (r != VM_PAGER_OK)
+ return (r);
+
+ /*
+ * If pager has replaced the page, assert that it had
+ * updated the array.
+ */
+ KASSERT(m[reqpage] == vm_page_lookup(object, m[reqpage]->pindex),
+ ("%s: mismatch page %p pindex %ju", __func__,
+ m[reqpage], (uintmax_t )m[reqpage]->pindex - 1));
+ /*
+ * Pager didn't fill up entire page. Zero out
+ * partially filled data.
+ */
+ if (m[reqpage]->valid != VM_PAGE_BITS_ALL)
+ vm_page_zero_invalid(m[reqpage], TRUE);
+
+ return (VM_PAGER_OK);
+}
+
+int
+vm_pager_get_pages_async(vm_object_t object, vm_page_t *m, int count,
+ int reqpage, pgo_getpages_iodone_t iodone, void *arg)
+{
+
+ VM_OBJECT_ASSERT_WLOCKED(object);
+ KASSERT(count > 0, ("%s: 0 count", __func__));
+
+ /*
+ * If the last page is partially valid, just return it and zero-out
+ * the blanks. Partially valid pages can only occur at the file EOF.
+ */
+ if (m[reqpage]->valid != 0) {
+ vm_page_zero_invalid(m[reqpage], TRUE);
+ iodone(arg, m, reqpage, 0);
+ return (VM_PAGER_OK);
+ }
+
+ return ((*pagertab[object->type]->pgo_getpages_async)(object, m,
+ count, reqpage, iodone, arg));
+}
+
+/*
* vm_pager_put_pages() - inline, see vm/vm_pager.h
* vm_pager_has_page() - inline, see vm/vm_pager.h
*/
Index: sys/vm/vm_pager.h
===================================================================
--- sys/vm/vm_pager.h (revision 284409)
+++ sys/vm/vm_pager.h (working copy)
@@ -106,9 +106,9 @@ vm_object_t vm_pager_allocate(objtype_t, void *, v
vm_ooffset_t, struct ucred *);
void vm_pager_bufferinit(void);
void vm_pager_deallocate(vm_object_t);
-static __inline int vm_pager_get_pages(vm_object_t, vm_page_t *, int, int);
-static inline int vm_pager_get_pages_async(vm_object_t, vm_page_t *, int,
- int, pgo_getpages_iodone_t, void *);
+int vm_pager_get_pages(vm_object_t, vm_page_t *, int, int);
+int vm_pager_get_pages_async(vm_object_t, vm_page_t *, int, int,
+ pgo_getpages_iodone_t, void *);
static __inline boolean_t vm_pager_has_page(vm_object_t, vm_pindex_t, int *, int *);
void vm_pager_init(void);
vm_object_t vm_pager_object_lookup(struct pagerlst *, void *);
@@ -115,40 +115,6 @@ vm_object_t vm_pager_object_lookup(struct pagerlst
void vm_pager_free_nonreq(vm_object_t object, vm_page_t ma[], int reqpage,
int npages, boolean_t object_locked);
-/*
- * vm_page_get_pages:
- *
- * Retrieve pages from the VM system in order to map them into an object
- * ( or into VM space somewhere ). If the pagein was successful, we
- * must fully validate it.
- */
-static __inline int
-vm_pager_get_pages(
- vm_object_t object,
- vm_page_t *m,
- int count,
- int reqpage
-) {
- int r;
-
- VM_OBJECT_ASSERT_WLOCKED(object);
- r = (*pagertab[object->type]->pgo_getpages)(object, m, count, reqpage);
- if (r == VM_PAGER_OK && m[reqpage]->valid != VM_PAGE_BITS_ALL) {
- vm_page_zero_invalid(m[reqpage], TRUE);
- }
- return (r);
-}
-
-static inline int
-vm_pager_get_pages_async(vm_object_t object, vm_page_t *m, int count,
- int reqpage, pgo_getpages_iodone_t iodone, void *arg)
-{
-
- VM_OBJECT_ASSERT_WLOCKED(object);
- return ((*pagertab[object->type]->pgo_getpages_async)(object, m,
- count, reqpage, iodone, arg));
-}
-
static __inline void
vm_pager_put_pages(
vm_object_t object,
Index: sys/vm/vnode_pager.c
===================================================================
--- sys/vm/vnode_pager.c (revision 284409)
+++ sys/vm/vnode_pager.c (working copy)
@@ -84,8 +84,6 @@ static int vnode_pager_addr(struct vnode *vp, vm_o
static int vnode_pager_input_smlfs(vm_object_t object, vm_page_t m);
static int vnode_pager_input_old(vm_object_t object, vm_page_t m);
static void vnode_pager_dealloc(vm_object_t);
-static int vnode_pager_local_getpages0(struct vnode *, vm_page_t *, int, int,
- vop_getpages_iodone_t, void *);
static int vnode_pager_getpages(vm_object_t, vm_page_t *, int, int);
static int vnode_pager_getpages_async(vm_object_t, vm_page_t *, int, int,
vop_getpages_iodone_t, void *);
@@ -714,7 +712,7 @@ int
vnode_pager_local_getpages(struct vop_getpages_args *ap)
{
- return (vnode_pager_local_getpages0(ap->a_vp, ap->a_m, ap->a_count,
+ return (vnode_pager_generic_getpages(ap->a_vp, ap->a_m, ap->a_count,
ap->a_reqpage, NULL, NULL));
}
@@ -722,42 +720,10 @@ int
vnode_pager_local_getpages_async(struct vop_getpages_async_args *ap)
{
- return (vnode_pager_local_getpages0(ap->a_vp, ap->a_m, ap->a_count,
+ return (vnode_pager_generic_getpages(ap->a_vp, ap->a_m, ap->a_count,
ap->a_reqpage, ap->a_iodone, ap->a_arg));
}
-static int
-vnode_pager_local_getpages0(struct vnode *vp, vm_page_t *m, int bytecount,
- int reqpage, vop_getpages_iodone_t iodone, void *arg)
-{
- vm_page_t mreq;
-
- mreq = m[reqpage];
-
- /*
- * Since the caller has busied the requested page, that page's valid
- * field will not be changed by other threads.
- */
- vm_page_assert_xbusied(mreq);
-
- /*
- * The requested page has valid blocks. Invalid part can only
- * exist at the end of file, and the page is made fully valid
- * by zeroing in vm_pager_get_pages(). Free non-requested
- * pages, since no i/o is done to read its content.
- */
- if (mreq->valid != 0) {
- vm_pager_free_nonreq(mreq->object, m, reqpage,
- round_page(bytecount) / PAGE_SIZE, FALSE);
- if (iodone != NULL)
- iodone(arg, m, reqpage, 0);
- return (VM_PAGER_OK);
- }
-
- return (vnode_pager_generic_getpages(vp, m, bytecount, reqpage,
- iodone, arg));
-}
-
/*
* This is now called from local media FS's to operate against their
* own vnodes if they fail to implement VOP_GETPAGES.
--t5NgoZwlhlUmGr82--
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