svn commit: r229618 - in stable/8/sys: fs/nfsserver nfsserver

John Baldwin jhb at FreeBSD.org
Thu Jan 5 18:50:38 UTC 2012


Author: jhb
Date: Thu Jan  5 18:50:37 2012
New Revision: 229618
URL: http://svn.freebsd.org/changeset/base/229618

Log:
  MFC 228185:
  Enhance the sequential access heuristic used to perform readahead in the
  NFS server and reuse it for writes as well to allow writes to the backing
  store to be clustered.

Modified:
  stable/8/sys/fs/nfsserver/nfs_nfsdport.c
  stable/8/sys/nfsserver/nfs_serv.c
Directory Properties:
  stable/8/sys/   (props changed)
  stable/8/sys/amd64/include/xen/   (props changed)
  stable/8/sys/cddl/contrib/opensolaris/   (props changed)
  stable/8/sys/contrib/dev/acpica/   (props changed)
  stable/8/sys/contrib/pf/   (props changed)

Modified: stable/8/sys/fs/nfsserver/nfs_nfsdport.c
==============================================================================
--- stable/8/sys/fs/nfsserver/nfs_nfsdport.c	Thu Jan  5 18:50:12 2012	(r229617)
+++ stable/8/sys/fs/nfsserver/nfs_nfsdport.c	Thu Jan  5 18:50:37 2012	(r229618)
@@ -86,20 +86,78 @@ SYSCTL_INT(_vfs_newnfs, OID_AUTO, issue_
 SYSCTL_INT(_vfs_newnfs, OID_AUTO, enable_locallocks, CTLFLAG_RW,
     &nfsrv_dolocallocks, 0, "Enable nfsd to acquire local locks on files");
 
-#define	NUM_HEURISTIC		1017
+#define	MAX_REORDERED_RPC	16
+#define	NUM_HEURISTIC		1031
 #define	NHUSE_INIT		64
 #define	NHUSE_INC		16
 #define	NHUSE_MAX		2048
 
 static struct nfsheur {
 	struct vnode *nh_vp;	/* vp to match (unreferenced pointer) */
-	off_t nh_nextr;		/* next offset for sequential detection */
+	off_t nh_nextoff;	/* next offset for sequential detection */
 	int nh_use;		/* use count for selection */
 	int nh_seqcount;	/* heuristic */
 } nfsheur[NUM_HEURISTIC];
 
 
 /*
+ * Heuristic to detect sequential operation.
+ */
+static struct nfsheur *
+nfsrv_sequential_heuristic(struct uio *uio, struct vnode *vp)
+{
+	struct nfsheur *nh;
+	int hi, try;
+
+	/* Locate best candidate. */
+	try = 32;
+	hi = ((int)(vm_offset_t)vp / sizeof(struct vnode)) % NUM_HEURISTIC;
+	nh = &nfsheur[hi];
+	while (try--) {
+		if (nfsheur[hi].nh_vp == vp) {
+			nh = &nfsheur[hi];
+			break;
+		}
+		if (nfsheur[hi].nh_use > 0)
+			--nfsheur[hi].nh_use;
+		hi = (hi + 1) % NUM_HEURISTIC;
+		if (nfsheur[hi].nh_use < nh->nh_use)
+			nh = &nfsheur[hi];
+	}
+
+	/* Initialize hint if this is a new file. */
+	if (nh->nh_vp != vp) {
+		nh->nh_vp = vp;
+		nh->nh_nextoff = uio->uio_offset;
+		nh->nh_use = NHUSE_INIT;
+		if (uio->uio_offset == 0)
+			nh->nh_seqcount = 4;
+		else
+			nh->nh_seqcount = 1;
+	}
+
+	/* Calculate heuristic. */
+	if ((uio->uio_offset == 0 && nh->nh_seqcount > 0) ||
+	    uio->uio_offset == nh->nh_nextoff) {
+		/* See comments in vfs_vnops.c:sequential_heuristic(). */
+		nh->nh_seqcount += howmany(uio->uio_resid, 16384);
+		if (nh->nh_seqcount > IO_SEQMAX)
+			nh->nh_seqcount = IO_SEQMAX;
+	} else if (qabs(uio->uio_offset - nh->nh_nextoff) <= MAX_REORDERED_RPC *
+	    imax(vp->v_mount->mnt_stat.f_iosize, uio->uio_resid)) {
+		/* Probably a reordered RPC, leave seqcount alone. */
+	} else if (nh->nh_seqcount > 1) {
+		nh->nh_seqcount /= 2;
+	} else {
+		nh->nh_seqcount = 0;
+	}
+	nh->nh_use += NHUSE_INC;
+	if (nh->nh_use > NHUSE_MAX)
+		nh->nh_use = NHUSE_MAX;
+	return (nh);
+}
+
+/*
  * Get attributes into nfsvattr structure.
  */
 int
@@ -562,60 +620,11 @@ nfsvno_read(struct vnode *vp, off_t off,
 	int i;
 	struct iovec *iv;
 	struct iovec *iv2;
-	int error = 0, len, left, siz, tlen, ioflag = 0, hi, try = 32;
+	int error = 0, len, left, siz, tlen, ioflag = 0;
 	struct mbuf *m2 = NULL, *m3;
 	struct uio io, *uiop = &io;
 	struct nfsheur *nh;
 
-	/*
-	 * Calculate seqcount for heuristic
-	 */
-	/*
-	 * Locate best candidate
-	 */
-
-	hi = ((int)(vm_offset_t)vp / sizeof(struct vnode)) % NUM_HEURISTIC;
-	nh = &nfsheur[hi];
-
-	while (try--) {
-		if (nfsheur[hi].nh_vp == vp) {
-			nh = &nfsheur[hi];
-			break;
-		}
-		if (nfsheur[hi].nh_use > 0)
-			--nfsheur[hi].nh_use;
-		hi = (hi + 1) % NUM_HEURISTIC;
-		if (nfsheur[hi].nh_use < nh->nh_use)
-			nh = &nfsheur[hi];
-	}
-
-	if (nh->nh_vp != vp) {
-		nh->nh_vp = vp;
-		nh->nh_nextr = off;
-		nh->nh_use = NHUSE_INIT;
-		if (off == 0)
-			nh->nh_seqcount = 4;
-		else
-			nh->nh_seqcount = 1;
-	}
-
-	/*
-	 * Calculate heuristic
-	 */
-
-	if ((off == 0 && nh->nh_seqcount > 0) || off == nh->nh_nextr) {
-		if (++nh->nh_seqcount > IO_SEQMAX)
-			nh->nh_seqcount = IO_SEQMAX;
-	} else if (nh->nh_seqcount > 1) {
-		nh->nh_seqcount = 1;
-	} else {
-		nh->nh_seqcount = 0;
-	}
-	nh->nh_use += NHUSE_INC;
-	if (nh->nh_use > NHUSE_MAX)
-		nh->nh_use = NHUSE_MAX;
-	ioflag |= nh->nh_seqcount << IO_SEQSHIFT;
-
 	len = left = NFSM_RNDUP(cnt);
 	m3 = NULL;
 	/*
@@ -660,6 +669,8 @@ nfsvno_read(struct vnode *vp, off_t off,
 	uiop->uio_resid = len;
 	uiop->uio_rw = UIO_READ;
 	uiop->uio_segflg = UIO_SYSSPACE;
+	nh = nfsrv_sequential_heuristic(uiop, vp);
+	ioflag |= nh->nh_seqcount << IO_SEQSHIFT;
 	error = VOP_READ(vp, uiop, IO_NODELOCKED | ioflag, cred);
 	FREE((caddr_t)iv2, M_TEMP);
 	if (error) {
@@ -667,6 +678,7 @@ nfsvno_read(struct vnode *vp, off_t off,
 		*mpp = NULL;
 		goto out;
 	}
+	nh->nh_nextoff = uiop->uio_offset;
 	tlen = len - uiop->uio_resid;
 	cnt = cnt < tlen ? cnt : tlen;
 	tlen = NFSM_RNDUP(cnt);
@@ -695,6 +707,7 @@ nfsvno_write(struct vnode *vp, off_t off
 	struct iovec *iv;
 	int ioflags, error;
 	struct uio io, *uiop = &io;
+	struct nfsheur *nh;
 
 	MALLOC(ivp, struct iovec *, cnt * sizeof (struct iovec), M_TEMP,
 	    M_WAITOK);
@@ -728,7 +741,11 @@ nfsvno_write(struct vnode *vp, off_t off
 	uiop->uio_segflg = UIO_SYSSPACE;
 	NFSUIOPROC(uiop, p);
 	uiop->uio_offset = off;
+	nh = nfsrv_sequential_heuristic(uiop, vp);
+	ioflags |= nh->nh_seqcount << IO_SEQSHIFT;
 	error = VOP_WRITE(vp, uiop, ioflags, cred);
+	if (error == 0)
+		nh->nh_nextoff = uiop->uio_offset;
 	FREE((caddr_t)iv, M_TEMP);
 
 	NFSEXITCODE(error);

Modified: stable/8/sys/nfsserver/nfs_serv.c
==============================================================================
--- stable/8/sys/nfsserver/nfs_serv.c	Thu Jan  5 18:50:12 2012	(r229617)
+++ stable/8/sys/nfsserver/nfs_serv.c	Thu Jan  5 18:50:37 2012	(r229618)
@@ -105,14 +105,15 @@ __FBSDID("$FreeBSD$");
 
 #define MAX_COMMIT_COUNT	(1024 * 1024)
 
-#define NUM_HEURISTIC		1017
+#define	MAX_REORDERED_RPC	16
+#define NUM_HEURISTIC		1031
 #define NHUSE_INIT		64
 #define NHUSE_INC		16
 #define NHUSE_MAX		2048
 
 static struct nfsheur {
 	struct vnode *nh_vp;	/* vp to match (unreferenced pointer) */
-	off_t nh_nextr;		/* next offset for sequential detection */
+	off_t nh_nextoff;	/* next offset for sequential detection */
 	int nh_use;		/* use count for selection */
 	int nh_seqcount;	/* heuristic */
 } nfsheur[NUM_HEURISTIC];
@@ -184,6 +185,63 @@ nfsrv_lockedpair_nd(int vfs1, struct nam
 }
 
 /*
+ * Heuristic to detect sequential operation.
+ */
+static struct nfsheur *
+nfsrv_sequential_heuristic(struct uio *uio, struct vnode *vp)
+{
+	struct nfsheur *nh;
+	int hi, try;
+
+	/* Locate best candidate. */
+	try = 32;
+	hi = ((int)(vm_offset_t)vp / sizeof(struct vnode)) % NUM_HEURISTIC;
+	nh = &nfsheur[hi];
+	while (try--) {
+		if (nfsheur[hi].nh_vp == vp) {
+			nh = &nfsheur[hi];
+			break;
+		}
+		if (nfsheur[hi].nh_use > 0)
+			--nfsheur[hi].nh_use;
+		hi = (hi + 1) % NUM_HEURISTIC;
+		if (nfsheur[hi].nh_use < nh->nh_use)
+			nh = &nfsheur[hi];
+	}
+
+	/* Initialize hint if this is a new file. */
+	if (nh->nh_vp != vp) {
+		nh->nh_vp = vp;
+		nh->nh_nextoff = uio->uio_offset;
+		nh->nh_use = NHUSE_INIT;
+		if (uio->uio_offset == 0)
+			nh->nh_seqcount = 4;
+		else
+			nh->nh_seqcount = 1;
+	}
+
+	/* Calculate heuristic. */
+	if ((uio->uio_offset == 0 && nh->nh_seqcount > 0) ||
+	    uio->uio_offset == nh->nh_nextoff) {
+		/* See comments in vfs_vnops.c:sequential_heuristic(). */
+		nh->nh_seqcount += howmany(uio->uio_resid, 16384);
+		if (nh->nh_seqcount > IO_SEQMAX)
+			nh->nh_seqcount = IO_SEQMAX;
+	} else if (qabs(uio->uio_offset - nh->nh_nextoff) <= MAX_REORDERED_RPC *
+	    imax(vp->v_mount->mnt_stat.f_iosize, uio->uio_resid)) {
+		/* Probably a reordered RPC, leave seqcount alone. */
+	} else if (nh->nh_seqcount > 1) {
+		nh->nh_seqcount /= 2;
+	} else {
+		nh->nh_seqcount = 0;
+	}
+	nh->nh_use += NHUSE_INC;
+	if (nh->nh_use > NHUSE_MAX)
+		nh->nh_use = NHUSE_MAX;
+	return (nh);
+}
+
+/*
  * nfs v3 access service
  */
 int
@@ -840,7 +898,6 @@ nfsrv_read(struct nfsrv_descript *nfsd, 
 	/*
 	 * Calculate byte count to read
 	 */
-
 	if (off >= vap->va_size)
 		cnt = 0;
 	else if ((off + reqlen) > vap->va_size)
@@ -848,61 +905,6 @@ nfsrv_read(struct nfsrv_descript *nfsd, 
 	else
 		cnt = reqlen;
 
-	/*
-	 * Calculate seqcount for heuristic
-	 */
-
-	{
-		int hi;
-		int try = 32;
-
-		/*
-		 * Locate best candidate
-		 */
-
-		hi = ((int)(vm_offset_t)vp / sizeof(struct vnode)) % NUM_HEURISTIC;
-		nh = &nfsheur[hi];
-
-		while (try--) {
-			if (nfsheur[hi].nh_vp == vp) {
-				nh = &nfsheur[hi];
-				break;
-			}
-			if (nfsheur[hi].nh_use > 0)
-				--nfsheur[hi].nh_use;
-			hi = (hi + 1) % NUM_HEURISTIC;
-			if (nfsheur[hi].nh_use < nh->nh_use)
-				nh = &nfsheur[hi];
-		}
-
-		if (nh->nh_vp != vp) {
-			nh->nh_vp = vp;
-			nh->nh_nextr = off;
-			nh->nh_use = NHUSE_INIT;
-			if (off == 0)
-				nh->nh_seqcount = 4;
-			else
-				nh->nh_seqcount = 1;
-		}
-
-		/*
-		 * Calculate heuristic
-		 */
-
-		if ((off == 0 && nh->nh_seqcount > 0) || off == nh->nh_nextr) {
-			if (++nh->nh_seqcount > IO_SEQMAX)
-				nh->nh_seqcount = IO_SEQMAX;
-		} else if (nh->nh_seqcount > 1) {
-			nh->nh_seqcount = 1;
-		} else {
-			nh->nh_seqcount = 0;
-		}
-		nh->nh_use += NHUSE_INC;
-		if (nh->nh_use > NHUSE_MAX)
-			nh->nh_use = NHUSE_MAX;
-		ioflag |= nh->nh_seqcount << IO_SEQSHIFT;
-        }
-
 	nfsm_reply(NFSX_POSTOPORFATTR(v3) + 3 * NFSX_UNSIGNED+nfsm_rndup(cnt));
 	if (v3) {
 		tl = nfsm_build(u_int32_t *, NFSX_V3FATTR + 4 * NFSX_UNSIGNED);
@@ -960,9 +962,11 @@ nfsrv_read(struct nfsrv_descript *nfsd, 
 		uiop->uio_resid = len;
 		uiop->uio_rw = UIO_READ;
 		uiop->uio_segflg = UIO_SYSSPACE;
+		nh = nfsrv_sequential_heuristic(uiop, vp);
+		ioflag |= nh->nh_seqcount << IO_SEQSHIFT;
 		error = VOP_READ(vp, uiop, IO_NODELOCKED | ioflag, cred);
-		off = uiop->uio_offset;
-		nh->nh_nextr = off;
+		if (error == 0)
+			nh->nh_nextoff = uiop->uio_offset;
 		free((caddr_t)iv2, M_TEMP);
 		if (error || (getret = VOP_GETATTR(vp, vap, cred))) {
 			if (!error)
@@ -1027,6 +1031,7 @@ nfsrv_write(struct nfsrv_descript *nfsd,
 	int v3 = (nfsd->nd_flag & ND_NFSV3);
 	struct mbuf *mb, *mreq;
 	struct vnode *vp = NULL;
+	struct nfsheur *nh;
 	nfsfh_t nfh;
 	fhandle_t *fhp;
 	struct uio io, *uiop = &io;
@@ -1167,7 +1172,11 @@ nfsrv_write(struct nfsrv_descript *nfsd,
 	    uiop->uio_segflg = UIO_SYSSPACE;
 	    uiop->uio_td = NULL;
 	    uiop->uio_offset = off;
+	    nh = nfsrv_sequential_heuristic(uiop, vp);
+	    ioflags |= nh->nh_seqcount << IO_SEQSHIFT;
 	    error = VOP_WRITE(vp, uiop, ioflags, cred);
+	    if (error == 0)
+		    nh->nh_nextoff = uiop->uio_offset;
 	    /* Unlocked write. */
 	    nfsrvstats.srvvop_writes++;
 	    free((caddr_t)iv, M_TEMP);


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