Update to FreeBSD 9.2

1 files changed, 866 insertions, 0 deletions

diff --git a/freebsd/sys/netpfil/ipfw/dn_sched_qfq.c b/freebsd/sys/netpfil/ipfw/dn_sched_qfq.c
new file mode 100644
index 00000000..461c40a5
--- /dev/null
+++ b/freebsd/sys/netpfil/ipfw/dn_sched_qfq.c
@@ -0,0 +1,866 @@
+#include <machine/rtems-bsd-kernel-space.h>
+
+/*
+ * Copyright (c) 2010 Fabio Checconi, Luigi Rizzo, Paolo Valente
+ * All rights reserved
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+/*
+ * $FreeBSD$
+ */
+
+#ifdef _KERNEL
+#include <sys/malloc.h>
+#include <sys/socket.h>
+#include <sys/socketvar.h>
+#include <sys/kernel.h>
+#include <sys/mbuf.h>
+#include <sys/module.h>
+#include <net/if.h>	/* IFNAMSIZ */
+#include <netinet/in.h>
+#include <netinet/ip_var.h>		/* ipfw_rule_ref */
+#include <netinet/ip_fw.h>	/* flow_id */
+#include <netinet/ip_dummynet.h>
+#include <netpfil/ipfw/dn_heap.h>
+#include <netpfil/ipfw/ip_dn_private.h>
+#include <netpfil/ipfw/dn_sched.h>
+#else
+#include <dn_test.h>
+#endif
+
+#ifdef QFQ_DEBUG
+struct qfq_sched;
+static void dump_sched(struct qfq_sched *q, const char *msg);
+#define	NO(x)	x
+#else
+#define NO(x)
+#endif
+#define DN_SCHED_QFQ	4 // XXX Where?
+typedef	unsigned long	bitmap;
+
+/*
+ * bitmaps ops are critical. Some linux versions have __fls
+ * and the bitmap ops. Some machines have ffs
+ */
+#if defined(_WIN32) || (defined(__MIPSEL__) && defined(LINUX_24))
+int fls(unsigned int n)
+{
+	int i = 0;
+	for (i = 0; n > 0; n >>= 1, i++)
+		;
+	return i;
+}
+#endif
+
+#if !defined(_KERNEL) || defined( __FreeBSD__ ) || defined(_WIN32) || (defined(__MIPSEL__) && defined(LINUX_24))
+static inline unsigned long __fls(unsigned long word)
+{
+	return fls(word) - 1;
+}
+#endif
+
+#if !defined(_KERNEL) || !defined(__linux__)
+#ifdef QFQ_DEBUG
+int test_bit(int ix, bitmap *p)
+{
+	if (ix < 0 || ix > 31)
+		D("bad index %d", ix);
+	return *p & (1<<ix);
+}
+void __set_bit(int ix, bitmap *p)
+{
+	if (ix < 0 || ix > 31)
+		D("bad index %d", ix);
+	*p |= (1<<ix);
+}
+void __clear_bit(int ix, bitmap *p)
+{
+	if (ix < 0 || ix > 31)
+		D("bad index %d", ix);
+	*p &= ~(1<<ix);
+}
+#else /* !QFQ_DEBUG */
+/* XXX do we have fast version, or leave it to the compiler ? */
+#define test_bit(ix, pData)	((*pData) & (1<<(ix)))
+#define __set_bit(ix, pData)	(*pData) |= (1<<(ix))
+#define __clear_bit(ix, pData)	(*pData) &= ~(1<<(ix))
+#endif /* !QFQ_DEBUG */
+#endif /* !__linux__ */
+
+#ifdef __MIPSEL__
+#define __clear_bit(ix, pData)	(*pData) &= ~(1<<(ix))
+#endif
+
+/*-------------------------------------------*/
+/*
+
+Virtual time computations.
+
+S, F and V are all computed in fixed point arithmetic with
+FRAC_BITS decimal bits.
+
+   QFQ_MAX_INDEX is the maximum index allowed for a group. We need
+  	one bit per index.
+   QFQ_MAX_WSHIFT is the maximum power of two supported as a weight.
+   The layout of the bits is as below:
+  
+                   [ MTU_SHIFT ][      FRAC_BITS    ]
+                   [ MAX_INDEX    ][ MIN_SLOT_SHIFT ]
+  				 ^.__grp->index = 0
+  				 *.__grp->slot_shift
+  
+   where MIN_SLOT_SHIFT is derived by difference from the others.
+
+The max group index corresponds to Lmax/w_min, where
+Lmax=1<<MTU_SHIFT, w_min = 1 .
+From this, and knowing how many groups (MAX_INDEX) we want,
+we can derive the shift corresponding to each group.
+
+Because we often need to compute
+	F = S + len/w_i  and V = V + len/wsum
+instead of storing w_i store the value
+	inv_w = (1<<FRAC_BITS)/w_i
+so we can do F = S + len * inv_w * wsum.
+We use W_TOT in the formulas so we can easily move between
+static and adaptive weight sum.
+
+The per-scheduler-instance data contain all the data structures
+for the scheduler: bitmaps and bucket lists.
+
+ */
+/*
+ * Maximum number of consecutive slots occupied by backlogged classes
+ * inside a group. This is approx lmax/lmin + 5.
+ * XXX check because it poses constraints on MAX_INDEX
+ */
+#define QFQ_MAX_SLOTS	32
+/*
+ * Shifts used for class<->group mapping. Class weights are
+ * in the range [1, QFQ_MAX_WEIGHT], we to map each class i to the
+ * group with the smallest index that can support the L_i / r_i
+ * configured for the class.
+ *
+ * grp->index is the index of the group; and grp->slot_shift
+ * is the shift for the corresponding (scaled) sigma_i.
+ *
+ * When computing the group index, we do (len<<FP_SHIFT)/weight,
+ * then compute an FLS (which is like a log2()), and if the result
+ * is below the MAX_INDEX region we use 0 (which is the same as
+ * using a larger len).
+ */
+#define QFQ_MAX_INDEX		19
+#define QFQ_MAX_WSHIFT		16	/* log2(max_weight) */
+
+#define	QFQ_MAX_WEIGHT		(1<<QFQ_MAX_WSHIFT)
+#define QFQ_MAX_WSUM		(2*QFQ_MAX_WEIGHT)
+//#define IWSUM	(q->i_wsum)
+#define IWSUM	((1<<FRAC_BITS)/QFQ_MAX_WSUM)
+
+#define FRAC_BITS		30	/* fixed point arithmetic */
+#define ONE_FP			(1UL << FRAC_BITS)
+
+#define QFQ_MTU_SHIFT		11	/* log2(max_len) */
+#define QFQ_MIN_SLOT_SHIFT	(FRAC_BITS + QFQ_MTU_SHIFT - QFQ_MAX_INDEX)
+
+/*
+ * Possible group states, also indexes for the bitmaps array in
+ * struct qfq_queue. We rely on ER, IR, EB, IB being numbered 0..3
+ */
+enum qfq_state { ER, IR, EB, IB, QFQ_MAX_STATE };
+
+struct qfq_group;
+/*
+ * additional queue info. Some of this info should come from
+ * the flowset, we copy them here for faster processing.
+ * This is an overlay of the struct dn_queue
+ */
+struct qfq_class {
+	struct dn_queue _q;
+	uint64_t S, F;		/* flow timestamps (exact) */
+	struct qfq_class *next; /* Link for the slot list. */
+
+	/* group we belong to. In principle we would need the index,
+	 * which is log_2(lmax/weight), but we never reference it
+	 * directly, only the group.
+	 */
+	struct qfq_group *grp;
+
+	/* these are copied from the flowset. */
+	uint32_t	inv_w;	/* ONE_FP/weight */
+	uint32_t 	lmax;	/* Max packet size for this flow. */
+};
+
+/* Group descriptor, see the paper for details.
+ * Basically this contains the bucket lists
+ */
+struct qfq_group {
+	uint64_t S, F;			/* group timestamps (approx). */
+	unsigned int slot_shift;	/* Slot shift. */
+	unsigned int index;		/* Group index. */
+	unsigned int front;		/* Index of the front slot. */
+	bitmap full_slots;		/* non-empty slots */
+
+	/* Array of lists of active classes. */
+	struct qfq_class *slots[QFQ_MAX_SLOTS];
+};
+
+/* scheduler instance descriptor. */
+struct qfq_sched {
+	uint64_t	V;		/* Precise virtual time. */
+	uint32_t	wsum;		/* weight sum */
+	NO(uint32_t	i_wsum;		/* ONE_FP/w_sum */
+	uint32_t	_queued;	/* debugging */
+	uint32_t	loops;	/* debugging */)
+	bitmap bitmaps[QFQ_MAX_STATE];	/* Group bitmaps. */
+	struct qfq_group groups[QFQ_MAX_INDEX + 1]; /* The groups. */
+};
+
+/*---- support functions ----------------------------*/
+
+/* Generic comparison function, handling wraparound. */
+static inline int qfq_gt(uint64_t a, uint64_t b)
+{
+	return (int64_t)(a - b) > 0;
+}
+
+/* Round a precise timestamp to its slotted value. */
+static inline uint64_t qfq_round_down(uint64_t ts, unsigned int shift)
+{
+	return ts & ~((1ULL << shift) - 1);
+}
+
+/* return the pointer to the group with lowest index in the bitmap */
+static inline struct qfq_group *qfq_ffs(struct qfq_sched *q,
+					unsigned long bitmap)
+{
+	int index = ffs(bitmap) - 1; // zero-based
+	return &q->groups[index];
+}
+
+/*
+ * Calculate a flow index, given its weight and maximum packet length.
+ * index = log_2(maxlen/weight) but we need to apply the scaling.
+ * This is used only once at flow creation.
+ */
+static int qfq_calc_index(uint32_t inv_w, unsigned int maxlen)
+{
+	uint64_t slot_size = (uint64_t)maxlen *inv_w;
+	unsigned long size_map;
+	int index = 0;
+
+	size_map = (unsigned long)(slot_size >> QFQ_MIN_SLOT_SHIFT);
+	if (!size_map)
+		goto out;
+
+	index = __fls(size_map) + 1;	// basically a log_2()
+	index -= !(slot_size - (1ULL << (index + QFQ_MIN_SLOT_SHIFT - 1)));
+
+	if (index < 0)
+		index = 0;
+
+out:
+	ND("W = %d, L = %d, I = %d\n", ONE_FP/inv_w, maxlen, index);
+	return index;
+}
+/*---- end support functions ----*/
+
+/*-------- API calls --------------------------------*/
+/*
+ * Validate and copy parameters from flowset.
+ */
+static int
+qfq_new_queue(struct dn_queue *_q)
+{
+	struct qfq_sched *q = (struct qfq_sched *)(_q->_si + 1);
+	struct qfq_class *cl = (struct qfq_class *)_q;
+	int i;
+	uint32_t w;	/* approximated weight */
+
+	/* import parameters from the flowset. They should be correct
+	 * already.
+	 */
+	w = _q->fs->fs.par[0];
+	cl->lmax = _q->fs->fs.par[1];
+	if (!w || w > QFQ_MAX_WEIGHT) {
+		w = 1;
+		D("rounding weight to 1");
+	}
+	cl->inv_w = ONE_FP/w;
+	w = ONE_FP/cl->inv_w;	
+	if (q->wsum + w > QFQ_MAX_WSUM)
+		return EINVAL;
+
+	i = qfq_calc_index(cl->inv_w, cl->lmax);
+	cl->grp = &q->groups[i];
+	q->wsum += w;
+	// XXX cl->S = q->V; ?
+	// XXX compute q->i_wsum
+	return 0;
+}
+
+/* remove an empty queue */
+static int
+qfq_free_queue(struct dn_queue *_q)
+{
+	struct qfq_sched *q = (struct qfq_sched *)(_q->_si + 1);
+	struct qfq_class *cl = (struct qfq_class *)_q;
+	if (cl->inv_w) {
+		q->wsum -= ONE_FP/cl->inv_w;
+		cl->inv_w = 0; /* reset weight to avoid run twice */
+	}
+	return 0;
+}
+
+/* Calculate a mask to mimic what would be ffs_from(). */
+static inline unsigned long
+mask_from(unsigned long bitmap, int from)
+{
+	return bitmap & ~((1UL << from) - 1);
+}
+
+/*
+ * The state computation relies on ER=0, IR=1, EB=2, IB=3
+ * First compute eligibility comparing grp->S, q->V,
+ * then check if someone is blocking us and possibly add EB
+ */
+static inline unsigned int
+qfq_calc_state(struct qfq_sched *q, struct qfq_group *grp)
+{
+	/* if S > V we are not eligible */
+	unsigned int state = qfq_gt(grp->S, q->V);
+	unsigned long mask = mask_from(q->bitmaps[ER], grp->index);
+	struct qfq_group *next;
+
+	if (mask) {
+		next = qfq_ffs(q, mask);
+		if (qfq_gt(grp->F, next->F))
+			state |= EB;
+	}
+
+	return state;
+}
+
+/*
+ * In principle
+ *	q->bitmaps[dst] |= q->bitmaps[src] & mask;
+ *	q->bitmaps[src] &= ~mask;
+ * but we should make sure that src != dst
+ */
+static inline void
+qfq_move_groups(struct qfq_sched *q, unsigned long mask, int src, int dst)
+{
+	q->bitmaps[dst] |= q->bitmaps[src] & mask;
+	q->bitmaps[src] &= ~mask;
+}
+
+static inline void
+qfq_unblock_groups(struct qfq_sched *q, int index, uint64_t old_finish)
+{
+	unsigned long mask = mask_from(q->bitmaps[ER], index + 1);
+	struct qfq_group *next;
+
+	if (mask) {
+		next = qfq_ffs(q, mask);
+		if (!qfq_gt(next->F, old_finish))
+			return;
+	}
+
+	mask = (1UL << index) - 1;
+	qfq_move_groups(q, mask, EB, ER);
+	qfq_move_groups(q, mask, IB, IR);
+}
+
+/*
+ * perhaps
+ *
+	old_V ^= q->V;
+	old_V >>= QFQ_MIN_SLOT_SHIFT;
+	if (old_V) {
+		...
+	}
+ *
+ */
+static inline void
+qfq_make_eligible(struct qfq_sched *q, uint64_t old_V)
+{
+	unsigned long mask, vslot, old_vslot;
+
+	vslot = q->V >> QFQ_MIN_SLOT_SHIFT;
+	old_vslot = old_V >> QFQ_MIN_SLOT_SHIFT;
+
+	if (vslot != old_vslot) {
+		mask = (2UL << (__fls(vslot ^ old_vslot))) - 1;
+		qfq_move_groups(q, mask, IR, ER);
+		qfq_move_groups(q, mask, IB, EB);
+	}
+}
+
+/*
+ * XXX we should make sure that slot becomes less than 32.
+ * This is guaranteed by the input values.
+ * roundedS is always cl->S rounded on grp->slot_shift bits.
+ */
+static inline void
+qfq_slot_insert(struct qfq_group *grp, struct qfq_class *cl, uint64_t roundedS)
+{
+	uint64_t slot = (roundedS - grp->S) >> grp->slot_shift;
+	unsigned int i = (grp->front + slot) % QFQ_MAX_SLOTS;
+
+	cl->next = grp->slots[i];
+	grp->slots[i] = cl;
+	__set_bit(slot, &grp->full_slots);
+}
+
+/*
+ * remove the entry from the slot
+ */
+static inline void
+qfq_front_slot_remove(struct qfq_group *grp)
+{
+	struct qfq_class **h = &grp->slots[grp->front];
+
+	*h = (*h)->next;
+	if (!*h)
+		__clear_bit(0, &grp->full_slots);
+}
+
+/*
+ * Returns the first full queue in a group. As a side effect,
+ * adjust the bucket list so the first non-empty bucket is at
+ * position 0 in full_slots.
+ */
+static inline struct qfq_class *
+qfq_slot_scan(struct qfq_group *grp)
+{
+	int i;
+
+	ND("grp %d full %x", grp->index, grp->full_slots);
+	if (!grp->full_slots)
+		return NULL;
+
+	i = ffs(grp->full_slots) - 1; // zero-based
+	if (i > 0) {
+		grp->front = (grp->front + i) % QFQ_MAX_SLOTS;
+		grp->full_slots >>= i;
+	}
+
+	return grp->slots[grp->front];
+}
+
+/*
+ * adjust the bucket list. When the start time of a group decreases,
+ * we move the index down (modulo QFQ_MAX_SLOTS) so we don't need to
+ * move the objects. The mask of occupied slots must be shifted
+ * because we use ffs() to find the first non-empty slot.
+ * This covers decreases in the group's start time, but what about
+ * increases of the start time ?
+ * Here too we should make sure that i is less than 32
+ */
+static inline void
+qfq_slot_rotate(struct qfq_sched *q, struct qfq_group *grp, uint64_t roundedS)
+{
+	unsigned int i = (grp->S - roundedS) >> grp->slot_shift;
+
+	grp->full_slots <<= i;
+	grp->front = (grp->front - i) % QFQ_MAX_SLOTS;
+}
+
+
+static inline void
+qfq_update_eligible(struct qfq_sched *q, uint64_t old_V)
+{
+	bitmap ineligible;
+
+	ineligible = q->bitmaps[IR] | q->bitmaps[IB];
+	if (ineligible) {
+		if (!q->bitmaps[ER]) {
+			struct qfq_group *grp;
+			grp = qfq_ffs(q, ineligible);
+			if (qfq_gt(grp->S, q->V))
+				q->V = grp->S;
+		}
+		qfq_make_eligible(q, old_V);
+	}
+}
+
+/*
+ * Updates the class, returns true if also the group needs to be updated.
+ */
+static inline int
+qfq_update_class(struct qfq_sched *q, struct qfq_group *grp,
+	    struct qfq_class *cl)
+{
+
+	cl->S = cl->F;
+	if (cl->_q.mq.head == NULL)  {
+		qfq_front_slot_remove(grp);
+	} else {
+		unsigned int len;
+		uint64_t roundedS;
+
+		len = cl->_q.mq.head->m_pkthdr.len;
+		cl->F = cl->S + (uint64_t)len * cl->inv_w;
+		roundedS = qfq_round_down(cl->S, grp->slot_shift);
+		if (roundedS == grp->S)
+			return 0;
+
+		qfq_front_slot_remove(grp);
+		qfq_slot_insert(grp, cl, roundedS);
+	}
+	return 1;
+}
+
+static struct mbuf *
+qfq_dequeue(struct dn_sch_inst *si)
+{
+	struct qfq_sched *q = (struct qfq_sched *)(si + 1);
+	struct qfq_group *grp;
+	struct qfq_class *cl;
+	struct mbuf *m;
+	uint64_t old_V;
+
+	NO(q->loops++;)
+	if (!q->bitmaps[ER]) {
+		NO(if (q->queued)
+			dump_sched(q, "start dequeue");)
+		return NULL;
+	}
+
+	grp = qfq_ffs(q, q->bitmaps[ER]);
+
+	cl = grp->slots[grp->front];
+	/* extract from the first bucket in the bucket list */
+	m = dn_dequeue(&cl->_q);
+
+	if (!m) {
+		D("BUG/* non-workconserving leaf */");
+		return NULL;
+	}
+	NO(q->queued--;)
+	old_V = q->V;
+	q->V += (uint64_t)m->m_pkthdr.len * IWSUM;
+	ND("m is %p F 0x%llx V now 0x%llx", m, cl->F, q->V);
+
+	if (qfq_update_class(q, grp, cl)) {
+		uint64_t old_F = grp->F;
+		cl = qfq_slot_scan(grp);
+		if (!cl) { /* group gone, remove from ER */
+			__clear_bit(grp->index, &q->bitmaps[ER]);
+			// grp->S = grp->F + 1; // XXX debugging only
+		} else {
+			uint64_t roundedS = qfq_round_down(cl->S, grp->slot_shift);
+			unsigned int s;
+
+			if (grp->S == roundedS)
+				goto skip_unblock;
+			grp->S = roundedS;
+			grp->F = roundedS + (2ULL << grp->slot_shift);
+			/* remove from ER and put in the new set */
+			__clear_bit(grp->index, &q->bitmaps[ER]);
+			s = qfq_calc_state(q, grp);
+			__set_bit(grp->index, &q->bitmaps[s]);
+		}
+		/* we need to unblock even if the group has gone away */
+		qfq_unblock_groups(q, grp->index, old_F);
+	}
+
+skip_unblock:
+	qfq_update_eligible(q, old_V);
+	NO(if (!q->bitmaps[ER] && q->queued)
+		dump_sched(q, "end dequeue");)
+
+	return m;
+}
+
+/*
+ * Assign a reasonable start time for a new flow k in group i.
+ * Admissible values for \hat(F) are multiples of \sigma_i
+ * no greater than V+\sigma_i . Larger values mean that
+ * we had a wraparound so we consider the timestamp to be stale.
+ *
+ * If F is not stale and F >= V then we set S = F.
+ * Otherwise we should assign S = V, but this may violate
+ * the ordering in ER. So, if we have groups in ER, set S to
+ * the F_j of the first group j which would be blocking us.
+ * We are guaranteed not to move S backward because
+ * otherwise our group i would still be blocked.
+ */
+static inline void
+qfq_update_start(struct qfq_sched *q, struct qfq_class *cl)
+{
+	unsigned long mask;
+	uint32_t limit, roundedF;
+	int slot_shift = cl->grp->slot_shift;
+
+	roundedF = qfq_round_down(cl->F, slot_shift);
+	limit = qfq_round_down(q->V, slot_shift) + (1UL << slot_shift);
+
+	if (!qfq_gt(cl->F, q->V) || qfq_gt(roundedF, limit)) {
+		/* timestamp was stale */
+		mask = mask_from(q->bitmaps[ER], cl->grp->index);
+		if (mask) {
+			struct qfq_group *next = qfq_ffs(q, mask);
+			if (qfq_gt(roundedF, next->F)) {
+				cl->S = next->F;
+				return;
+			}
+		}
+		cl->S = q->V;
+	} else { /* timestamp is not stale */
+		cl->S = cl->F;
+	}
+}
+
+static int
+qfq_enqueue(struct dn_sch_inst *si, struct dn_queue *_q, struct mbuf *m)
+{
+	struct qfq_sched *q = (struct qfq_sched *)(si + 1);
+	struct qfq_group *grp;
+	struct qfq_class *cl = (struct qfq_class *)_q;
+	uint64_t roundedS;
+	int s;
+
+	NO(q->loops++;)
+	DX(4, "len %d flow %p inv_w 0x%x grp %d", m->m_pkthdr.len,
+		_q, cl->inv_w, cl->grp->index);
+	/* XXX verify that the packet obeys the parameters */
+	if (m != _q->mq.head) {
+		if (dn_enqueue(_q, m, 0)) /* packet was dropped */
+			return 1;
+		NO(q->queued++;)
+		if (m != _q->mq.head)
+			return 0;
+	}
+	/* If reach this point, queue q was idle */
+	grp = cl->grp;
+	qfq_update_start(q, cl); /* adjust start time */
+	/* compute new finish time and rounded start. */
+	cl->F = cl->S + (uint64_t)(m->m_pkthdr.len) * cl->inv_w;
+	roundedS = qfq_round_down(cl->S, grp->slot_shift);
+
+	/*
+	 * insert cl in the correct bucket.
+	 * If cl->S >= grp->S we don't need to adjust the
+	 * bucket list and simply go to the insertion phase.
+	 * Otherwise grp->S is decreasing, we must make room
+	 * in the bucket list, and also recompute the group state.
+	 * Finally, if there were no flows in this group and nobody
+	 * was in ER make sure to adjust V.
+	 */
+	if (grp->full_slots) {
+		if (!qfq_gt(grp->S, cl->S))
+			goto skip_update;
+		/* create a slot for this cl->S */
+		qfq_slot_rotate(q, grp, roundedS);
+		/* group was surely ineligible, remove */
+		__clear_bit(grp->index, &q->bitmaps[IR]);
+		__clear_bit(grp->index, &q->bitmaps[IB]);
+	} else if (!q->bitmaps[ER] && qfq_gt(roundedS, q->V))
+		q->V = roundedS;
+
+	grp->S = roundedS;
+	grp->F = roundedS + (2ULL << grp->slot_shift); // i.e. 2\sigma_i
+	s = qfq_calc_state(q, grp);
+	__set_bit(grp->index, &q->bitmaps[s]);
+	ND("new state %d 0x%x", s, q->bitmaps[s]);
+	ND("S %llx F %llx V %llx", cl->S, cl->F, q->V);
+skip_update:
+	qfq_slot_insert(grp, cl, roundedS);
+
+	return 0;
+}
+
+
+#if 0
+static inline void
+qfq_slot_remove(struct qfq_sched *q, struct qfq_group *grp,
+	struct qfq_class *cl, struct qfq_class **pprev)
+{
+	unsigned int i, offset;
+	uint64_t roundedS;
+
+	roundedS = qfq_round_down(cl->S, grp->slot_shift);
+	offset = (roundedS - grp->S) >> grp->slot_shift;
+	i = (grp->front + offset) % QFQ_MAX_SLOTS;
+
+#ifdef notyet
+	if (!pprev) {
+		pprev = &grp->slots[i];
+		while (*pprev && *pprev != cl)
+			pprev = &(*pprev)->next;
+	}
+#endif
+
+	*pprev = cl->next;
+	if (!grp->slots[i])
+		__clear_bit(offset, &grp->full_slots);
+}
+
+/*
+ * called to forcibly destroy a queue.
+ * If the queue is not in the front bucket, or if it has
+ * other queues in the front bucket, we can simply remove
+ * the queue with no other side effects.
+ * Otherwise we must propagate the event up.
+ * XXX description to be completed.
+ */
+static void
+qfq_deactivate_class(struct qfq_sched *q, struct qfq_class *cl,
+				 struct qfq_class **pprev)
+{
+	struct qfq_group *grp = &q->groups[cl->index];
+	unsigned long mask;
+	uint64_t roundedS;
+	int s;
+
+	cl->F = cl->S;	// not needed if the class goes away.
+	qfq_slot_remove(q, grp, cl, pprev);
+
+	if (!grp->full_slots) {
+		/* nothing left in the group, remove from all sets.
+		 * Do ER last because if we were blocking other groups
+		 * we must unblock them.
+		 */
+		__clear_bit(grp->index, &q->bitmaps[IR]);
+		__clear_bit(grp->index, &q->bitmaps[EB]);
+		__clear_bit(grp->index, &q->bitmaps[IB]);
+
+		if (test_bit(grp->index, &q->bitmaps[ER]) &&
+		    !(q->bitmaps[ER] & ~((1UL << grp->index) - 1))) {
+			mask = q->bitmaps[ER] & ((1UL << grp->index) - 1);
+			if (mask)
+				mask = ~((1UL << __fls(mask)) - 1);
+			else
+				mask = ~0UL;
+			qfq_move_groups(q, mask, EB, ER);
+			qfq_move_groups(q, mask, IB, IR);
+		}
+		__clear_bit(grp->index, &q->bitmaps[ER]);
+	} else if (!grp->slots[grp->front]) {
+		cl = qfq_slot_scan(grp);
+		roundedS = qfq_round_down(cl->S, grp->slot_shift);
+		if (grp->S != roundedS) {
+			__clear_bit(grp->index, &q->bitmaps[ER]);
+			__clear_bit(grp->index, &q->bitmaps[IR]);
+			__clear_bit(grp->index, &q->bitmaps[EB]);
+			__clear_bit(grp->index, &q->bitmaps[IB]);
+			grp->S = roundedS;
+			grp->F = roundedS + (2ULL << grp->slot_shift);
+			s = qfq_calc_state(q, grp);
+			__set_bit(grp->index, &q->bitmaps[s]);
+		}
+	}
+	qfq_update_eligible(q, q->V);
+}
+#endif
+
+static int
+qfq_new_fsk(struct dn_fsk *f)
+{
+	ipdn_bound_var(&f->fs.par[0], 1, 1, QFQ_MAX_WEIGHT, "qfq weight");
+	ipdn_bound_var(&f->fs.par[1], 1500, 1, 2000, "qfq maxlen");
+	ND("weight %d len %d\n", f->fs.par[0], f->fs.par[1]);
+	return 0;
+}
+
+/*
+ * initialize a new scheduler instance
+ */
+static int
+qfq_new_sched(struct dn_sch_inst *si)
+{
+	struct qfq_sched *q = (struct qfq_sched *)(si + 1);
+	struct qfq_group *grp;
+	int i;
+
+	for (i = 0; i <= QFQ_MAX_INDEX; i++) {
+		grp = &q->groups[i];
+		grp->index = i;
+		grp->slot_shift = QFQ_MTU_SHIFT + FRAC_BITS -
+					(QFQ_MAX_INDEX - i);
+	}
+	return 0;
+}
+
+/*
+ * QFQ scheduler descriptor
+ */
+static struct dn_alg qfq_desc = {
+	_SI( .type = ) DN_SCHED_QFQ,
+	_SI( .name = ) "QFQ",
+	_SI( .flags = ) DN_MULTIQUEUE,
+
+	_SI( .schk_datalen = ) 0,
+	_SI( .si_datalen = ) sizeof(struct qfq_sched),
+	_SI( .q_datalen = ) sizeof(struct qfq_class) - sizeof(struct dn_queue),
+
+	_SI( .enqueue = ) qfq_enqueue,
+	_SI( .dequeue = ) qfq_dequeue,
+
+	_SI( .config = )  NULL,
+	_SI( .destroy = )  NULL,
+	_SI( .new_sched = ) qfq_new_sched,
+	_SI( .free_sched = )  NULL,
+	_SI( .new_fsk = ) qfq_new_fsk,
+	_SI( .free_fsk = )  NULL,
+	_SI( .new_queue = ) qfq_new_queue,
+	_SI( .free_queue = ) qfq_free_queue,
+};
+
+DECLARE_DNSCHED_MODULE(dn_qfq, &qfq_desc);
+
+#ifdef QFQ_DEBUG
+static void
+dump_groups(struct qfq_sched *q, uint32_t mask)
+{
+	int i, j;
+
+	for (i = 0; i < QFQ_MAX_INDEX + 1; i++) {
+		struct qfq_group *g = &q->groups[i];
+
+		if (0 == (mask & (1<<i)))
+			continue;
+		for (j = 0; j < QFQ_MAX_SLOTS; j++) {
+			if (g->slots[j])
+				D("    bucket %d %p", j, g->slots[j]);
+		}
+		D("full_slots 0x%x", g->full_slots);
+		D("        %2d S 0x%20llx F 0x%llx %c", i,
+			g->S, g->F,
+			mask & (1<<i) ? '1' : '0');
+	}
+}
+
+static void
+dump_sched(struct qfq_sched *q, const char *msg)
+{
+	D("--- in %s: ---", msg);
+	ND("loops %d queued %d V 0x%llx", q->loops, q->queued, q->V);
+	D("    ER 0x%08x", q->bitmaps[ER]);
+	D("    EB 0x%08x", q->bitmaps[EB]);
+	D("    IR 0x%08x", q->bitmaps[IR]);
+	D("    IB 0x%08x", q->bitmaps[IB]);
+	dump_groups(q, 0xffffffff);
+};
+#endif /* QFQ_DEBUG */