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Use buffer pager for NFS.

Browse Source 
The pager, due to its construction, implements clustering for the
page-ins.  In particular, buildworld load demonstrates reduction of
the READ RPCs from 39k down to 24k.  No change in real or CPU time was
observed.

Discussed with, and measured by:	bde
No objections from:	rmacklem
Tested by:	pho
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
This commit is contained in:
Konstantin Belousov 2016-11-22 10:58:24 +00:00
parent fc2c3afee0
commit 753a007f0d
2 changed files with 48 additions and 3 deletions
sys/fs/nfsclient
nfs_clbio.cnfs_clvnops.c

38
sys/fs/nfsclient/nfs_clbio.c

@ -78,6 +78,40 @@ static int nfs_directio_write(struct vnode *vp, struct uio *uiop,
/*
* Vnode op for VM getpages.
*/
SYSCTL_DECL(_vfs_nfs);
static int use_buf_pager = 1;
SYSCTL_INT(_vfs_nfs, OID_AUTO, use_buf_pager, CTLFLAG_RWTUN,
&use_buf_pager, 0,
"Use buffer pager instead of direct readrpc call");
static daddr_t
ncl_gbp_getblkno(struct vnode *vp, vm_ooffset_t off)
{
return (off / vp->v_bufobj.bo_bsize);
}
static int
ncl_gbp_getblksz(struct vnode *vp, daddr_t lbn)
{
struct nfsnode *np;
u_quad_t nsize;
int biosize, bcount;
np = VTONFS(vp);
mtx_lock(&np->n_mtx);
nsize = np->n_size;
mtx_unlock(&np->n_mtx);
biosize = vp->v_bufobj.bo_bsize;
bcount = biosize;
if ((off_t)lbn * biosize >= nsize)
bcount = 0;
else if ((off_t)(lbn + 1) * biosize > nsize)
bcount = nsize - (off_t)lbn * biosize;
return (bcount);
}
int
ncl_getpages(struct vop_getpages_args *ap)
{
@ -126,6 +160,10 @@ ncl_getpages(struct vop_getpages_args *ap)
} else
mtx_unlock(&nmp->nm_mtx);
if (use_buf_pager)
return (vfs_bio_getpages(vp, pages, npages, ap->a_rbehind,
ap->a_rahead, ncl_gbp_getblkno, ncl_gbp_getblksz));
/*
* If the requested page is partially valid, just return it and
* allow the pager to zero-out the blanks. Partially valid pages

13
sys/fs/nfsclient/nfs_clvnops.c

@ -2569,13 +2569,20 @@ ncl_commit(struct vnode *vp, u_quad_t offset, int cnt, struct ucred *cred,
static int
nfs_strategy(struct vop_strategy_args *ap)
{
struct buf *bp = ap->a_bp;
struct buf *bp;
struct vnode *vp;
struct ucred *cr;
bp = ap->a_bp;
vp = ap->a_vp;
KASSERT(bp->b_vp == vp, ("missing b_getvp"));
KASSERT(!(bp->b_flags & B_DONE),
("nfs_strategy: buffer %p unexpectedly marked B_DONE", bp));
BUF_ASSERT_HELD(bp);
if (vp->v_type == VREG && bp->b_blkno == bp->b_lblkno)
bp->b_blkno = bp->b_lblkno * (vp->v_bufobj.bo_bsize /
DEV_BSIZE);
if (bp->b_iocmd == BIO_READ)
cr = bp->b_rcred;
else
@ -2587,8 +2594,8 @@ nfs_strategy(struct vop_strategy_args *ap)
* otherwise just do it ourselves.
*/
if ((bp->b_flags & B_ASYNC) == 0 ||
ncl_asyncio(VFSTONFS(ap->a_vp->v_mount), bp, NOCRED, curthread))
(void) ncl_doio(ap->a_vp, bp, cr, curthread, 1);
ncl_asyncio(VFSTONFS(vp->v_mount), bp, NOCRED, curthread))
(void) ncl_doio(vp, bp, cr, curthread, 1);
return (0);
}