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zfs: add vop_getpages method implementation

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This should make vnode_pager_getpages path a bit shorter and clearer.
Also this should eliminate problems with partially valid pages.
Having this method opens room for future optimizations.

To do: try to satisfy other pages besides the required one taking into
account tradeofs between number of page faults, read throughput and read
latency.  Also, eventually vop_putpages should be added too.

Reviewed by:	kib, mm, pjd
MFC after:	3 weeks
This commit is contained in:
Andriy Gapon 2010-10-16 20:43:05 +00:00
parent 12112cf676
commit 23a1bcf8c6
1 changed files with 91 additions and 0 deletions
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91
sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c
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@ -4198,6 +4198,96 @@ ioflags(int ioflags)
return (flags);
}
static int
zfs_getpages(struct vnode *vp, vm_page_t *m, int count, int reqpage)
{
znode_t *zp = VTOZ(vp);
zfsvfs_t *zfsvfs = zp->z_zfsvfs;
objset_t *os = zp->z_zfsvfs->z_os;
vm_page_t mreq;
vm_object_t object;
caddr_t va;
struct sf_buf *sf;
int i, error;
int pcount, size;
ZFS_ENTER(zfsvfs);
ZFS_VERIFY_ZP(zp);
pcount = round_page(count) / PAGE_SIZE;
mreq = m[reqpage];
object = mreq->object;
error = 0;
KASSERT(vp->v_object == object, ("mismatching object"));
VM_OBJECT_LOCK(object);
for (i = 0; i < pcount; i++) {
if (i != reqpage) {
vm_page_lock(m[i]);
vm_page_free(m[i]);
vm_page_unlock(m[i]);
}
}
if (mreq->valid) {
if (mreq->valid != VM_PAGE_BITS_ALL)
vm_page_zero_invalid(mreq, TRUE);
VM_OBJECT_UNLOCK(object);
ZFS_EXIT(zfsvfs);
return (VM_PAGER_OK);
}
PCPU_INC(cnt.v_vnodein);
PCPU_INC(cnt.v_vnodepgsin);
if (IDX_TO_OFF(mreq->pindex) >= object->un_pager.vnp.vnp_size) {
VM_OBJECT_UNLOCK(object);
ZFS_EXIT(zfsvfs);
return (VM_PAGER_BAD);
}
size = PAGE_SIZE;
if (IDX_TO_OFF(mreq->pindex) + size > object->un_pager.vnp.vnp_size)
size = object->un_pager.vnp.vnp_size - IDX_TO_OFF(mreq->pindex);
VM_OBJECT_UNLOCK(object);
va = zfs_map_page(mreq, &sf);
error = dmu_read(os, zp->z_id, IDX_TO_OFF(mreq->pindex),
size, va, DMU_READ_PREFETCH);
if (size != PAGE_SIZE)
bzero(va + size, PAGE_SIZE - size);
zfs_unmap_page(sf);
VM_OBJECT_LOCK(object);
if (!error)
mreq->valid = VM_PAGE_BITS_ALL;
KASSERT(mreq->dirty == 0, ("zfs_getpages: page %p is dirty", mreq));
VM_OBJECT_UNLOCK(object);
ZFS_ACCESSTIME_STAMP(zfsvfs, zp);
ZFS_EXIT(zfsvfs);
return (error ? VM_PAGER_ERROR : VM_PAGER_OK);
}
static int
zfs_freebsd_getpages(ap)
struct vop_getpages_args /* {
struct vnode *a_vp;
vm_page_t *a_m;
int a_count;
int a_reqpage;
vm_ooffset_t a_offset;
} */ *ap;
{
return (zfs_getpages(ap->a_vp, ap->a_m, ap->a_count, ap->a_reqpage));
}
static int
zfs_freebsd_open(ap)
struct vop_open_args /* {
@ -5314,6 +5404,7 @@ struct vop_vector zfs_vnodeops = {
.vop_getacl = zfs_freebsd_getacl,
.vop_setacl = zfs_freebsd_setacl,
.vop_aclcheck = zfs_freebsd_aclcheck,
.vop_getpages = zfs_freebsd_getpages,
};
struct vop_vector zfs_fifoops = {