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      1 /*	$NetBSD: altq_rmclass.c,v 1.32 2025/01/08 13:00:04 joe Exp $	*/
      2 /*	$KAME: altq_rmclass.c,v 1.19 2005/04/13 03:44:25 suz Exp $	*/
      3 
      4 /*
      5  * Copyright (c) 1991-1997 Regents of the University of California.
      6  * All rights reserved.
      7  *
      8  * Redistribution and use in source and binary forms, with or without
      9  * modification, are permitted provided that the following conditions
     10  * are met:
     11  * 1. Redistributions of source code must retain the above copyright
     12  *    notice, this list of conditions and the following disclaimer.
     13  * 2. Redistributions in binary form must reproduce the above copyright
     14  *    notice, this list of conditions and the following disclaimer in the
     15  *    documentation and/or other materials provided with the distribution.
     16  * 3. All advertising materials mentioning features or use of this software
     17  *    must display the following acknowledgement:
     18  *      This product includes software developed by the Network Research
     19  *      Group at Lawrence Berkeley Laboratory.
     20  * 4. Neither the name of the University nor of the Laboratory may be used
     21  *    to endorse or promote products derived from this software without
     22  *    specific prior written permission.
     23  *
     24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     34  * SUCH DAMAGE.
     35  *
     36  * LBL code modified by speer (at) eng.sun.com, May 1977.
     37  * For questions and/or comments, please send mail to cbq (at) ee.lbl.gov
     38  */
     39 
     40 #include <sys/cdefs.h>
     41 __KERNEL_RCSID(0, "$NetBSD: altq_rmclass.c,v 1.32 2025/01/08 13:00:04 joe Exp $");
     42 
     43 /* #ident "@(#)rm_class.c  1.48     97/12/05 SMI" */
     44 
     45 #ifdef _KERNEL_OPT
     46 #include "opt_altq.h"
     47 #include "opt_inet.h"
     48 #endif
     49 
     50 #ifdef ALTQ_CBQ	/* cbq is enabled by ALTQ_CBQ option in opt_altq.h */
     51 
     52 #include <sys/param.h>
     53 #include <sys/malloc.h>
     54 #include <sys/mbuf.h>
     55 #include <sys/socket.h>
     56 #include <sys/systm.h>
     57 #include <sys/errno.h>
     58 #include <sys/time.h>
     59 #ifdef ALTQ3_COMPAT
     60 #include <sys/kernel.h>
     61 #endif
     62 #include <sys/cprng.h>
     63 
     64 #include <net/if.h>
     65 #include <net/if_types.h>
     66 #ifdef ALTQ3_COMPAT
     67 #include <netinet/in.h>
     68 #include <netinet/in_systm.h>
     69 #include <netinet/ip.h>
     70 #endif
     71 
     72 #include <altq/altq.h>
     73 #include <altq/altq_rmclass.h>
     74 #include <altq/altq_rmclass_debug.h>
     75 #include <altq/altq_red.h>
     76 #include <altq/altq_rio.h>
     77 
     78 /*
     79  * Local Macros
     80  */
     81 
     82 #define	reset_cutoff(ifd)	{ ifd->cutoff_ = RM_MAXDEPTH; }
     83 
     84 #define	PSEC_TO_NSEC(t)	((t) / 1000)
     85 
     86 /*
     87  * Local routines.
     88  */
     89 
     90 static int	rmc_satisfied(struct rm_class *, struct timespec *);
     91 static void	rmc_wrr_set_weights(struct rm_ifdat *);
     92 static void	rmc_depth_compute(struct rm_class *);
     93 static void	rmc_depth_recompute(rm_class_t *);
     94 
     95 static mbuf_t	*_rmc_wrr_dequeue_next(struct rm_ifdat *, int);
     96 static mbuf_t	*_rmc_prr_dequeue_next(struct rm_ifdat *, int);
     97 
     98 static int	_rmc_addq(rm_class_t *, mbuf_t *);
     99 static void	_rmc_dropq(rm_class_t *);
    100 static mbuf_t	*_rmc_getq(rm_class_t *);
    101 static mbuf_t	*_rmc_pollq(rm_class_t *);
    102 
    103 static int	rmc_under_limit(struct rm_class *, struct timespec *);
    104 static void	rmc_tl_satisfied(struct rm_ifdat *, struct timespec *);
    105 static void	rmc_drop_action(struct rm_class *);
    106 static void	rmc_restart(struct rm_class *);
    107 static void	rmc_root_overlimit(struct rm_class *, struct rm_class *);
    108 
    109 #define	BORROW_OFFTIME
    110 /*
    111  * BORROW_OFFTIME (experimental):
    112  * borrow the offtime of the class borrowing from.
    113  * the reason is that when its own offtime is set, the class is unable
    114  * to borrow much, especially when cutoff is taking effect.
    115  * but when the borrowed class is overloaded (advidle is close to minidle),
    116  * use the borrowing class's offtime to avoid overload.
    117  */
    118 #define	ADJUST_CUTOFF
    119 /*
    120  * ADJUST_CUTOFF (experimental):
    121  * if no underlimit class is found due to cutoff, increase cutoff and
    122  * retry the scheduling loop.
    123  * also, don't invoke delay_actions while cutoff is taking effect,
    124  * since a sleeping class won't have a chance to be scheduled in the
    125  * next loop.
    126  *
    127  * now heuristics for setting the top-level variable (cutoff_) becomes:
    128  *	1. if a packet arrives for a not-overlimit class, set cutoff
    129  *	   to the depth of the class.
    130  *	2. if cutoff is i, and a packet arrives for an overlimit class
    131  *	   with an underlimit ancestor at a lower level than i (say j),
    132  *	   then set cutoff to j.
    133  *	3. at scheduling a packet, if there is no underlimit class
    134  *	   due to the current cutoff level, increase cutoff by 1 and
    135  *	   then try to schedule again.
    136  */
    137 
    138 /*
    139  * rm_class_t *
    140  * rmc_newclass(...) - Create a new resource management class at priority
    141  * 'pri' on the interface given by 'ifd'.
    142  *
    143  * nsecPerByte  is the data rate of the interface in nanoseconds/byte.
    144  *              E.g., 800 for a 10Mb/s ethernet.  If the class gets less
    145  *              than 100% of the bandwidth, this number should be the
    146  *              'effective' rate for the class.  Let f be the
    147  *              bandwidth fraction allocated to this class, and let
    148  *              nsPerByte be the data rate of the output link in
    149  *              nanoseconds/byte.  Then nsecPerByte is set to
    150  *              nsPerByte / f.  E.g., 1600 (= 800 / .5)
    151  *              for a class that gets 50% of an ethernet's bandwidth.
    152  *
    153  * action       the routine to call when the class is over limit.
    154  *
    155  * maxq         max allowable queue size for class (in packets).
    156  *
    157  * parent       parent class pointer.
    158  *
    159  * borrow       class to borrow from (should be either 'parent' or null).
    160  *
    161  * maxidle      max value allowed for class 'idle' time estimate (this
    162  *              parameter determines how large an initial burst of packets
    163  *              can be before overlimit action is invoked.
    164  *
    165  * offtime      how long 'delay' action will delay when class goes over
    166  *              limit (this parameter determines the steady-state burst
    167  *              size when a class is running over its limit).
    168  *
    169  * Maxidle and offtime have to be computed from the following:  If the
    170  * average packet size is s, the bandwidth fraction allocated to this
    171  * class is f, we want to allow b packet bursts, and the gain of the
    172  * averaging filter is g (= 1 - 2^(-RM_FILTER_GAIN)), then:
    173  *
    174  *   ptime = s * nsPerByte * (1 - f) / f
    175  *   maxidle = ptime * (1 - g^b) / g^b
    176  *   minidle = -ptime * (1 / (f - 1))
    177  *   offtime = ptime * (1 + 1/(1 - g) * (1 - g^(b - 1)) / g^(b - 1)
    178  *
    179  * Operationally, it's convenient to specify maxidle & offtime in units
    180  * independent of the link bandwidth so the maxidle & offtime passed to
    181  * this routine are the above values multiplied by 8*f/(1000*nsPerByte).
    182  * (The constant factor is a scale factor needed to make the parameters
    183  * integers.  This scaling also means that the 'unscaled' values of
    184  * maxidle*nsecPerByte/8 and offtime*nsecPerByte/8 will be in microseconds,
    185  * not nanoseconds.)  Also note that the 'idle' filter computation keeps
    186  * an estimate scaled upward by 2^RM_FILTER_GAIN so the passed value of
    187  * maxidle also must be scaled upward by this value.  Thus, the passed
    188  * values for maxidle and offtime can be computed as follows:
    189  *
    190  * maxidle = maxidle * 2^RM_FILTER_GAIN * 8 / (1000 * nsecPerByte)
    191  * offtime = offtime * 8 / (1000 * nsecPerByte)
    192  *
    193  * When USE_HRTIME is employed, then maxidle and offtime become:
    194  * 	maxidle = maxilde * (8.0 / nsecPerByte);
    195  * 	offtime = offtime * (8.0 / nsecPerByte);
    196  */
    197 struct rm_class *
    198 rmc_newclass(int pri, struct rm_ifdat *ifd, uint64_t psecPerByte,
    199     void (*action)(rm_class_t *, rm_class_t *), int maxq,
    200     struct rm_class *parent, struct rm_class *borrow, u_int maxidle,
    201     int minidle, u_int offtime, int pktsize, int flags)
    202 {
    203 	struct rm_class	*cl;
    204 	struct rm_class	*peer;
    205 	int		 s;
    206 
    207 	if (pri >= RM_MAXPRIO)
    208 		return NULL;
    209 #ifndef ALTQ_RED
    210 	if (flags & RMCF_RED) {
    211 #ifdef ALTQ_DEBUG
    212 		printf("rmc_newclass: RED not configured for CBQ!\n");
    213 #endif
    214 		return NULL;
    215 	}
    216 #endif
    217 #ifndef ALTQ_RIO
    218 	if (flags & RMCF_RIO) {
    219 #ifdef ALTQ_DEBUG
    220 		printf("rmc_newclass: RIO not configured for CBQ!\n");
    221 #endif
    222 		return NULL;
    223 	}
    224 #endif
    225 
    226 	cl = malloc(sizeof(struct rm_class), M_DEVBUF, M_WAITOK|M_ZERO);
    227 	if (cl == NULL)
    228 		return NULL;
    229 	CALLOUT_INIT(&cl->callout_);
    230 
    231 	cl->q_ = malloc(sizeof(class_queue_t), M_DEVBUF, M_WAITOK|M_ZERO);
    232 	if (cl->q_ == NULL) {
    233 		free(cl, M_DEVBUF);
    234 		return NULL;
    235 	}
    236 
    237 	/*
    238 	 * Class initialization.
    239 	 */
    240 	cl->children_ = NULL;
    241 	cl->parent_ = parent;
    242 	cl->borrow_ = borrow;
    243 	cl->leaf_ = 1;
    244 	cl->ifdat_ = ifd;
    245 	cl->pri_ = pri;
    246 	cl->allotment_ = (u_int)(RM_PS_PER_SEC / psecPerByte); /* Bytes per sec */
    247 	cl->depth_ = 0;
    248 	cl->qthresh_ = 0;
    249 	cl->ps_per_byte_ = psecPerByte;
    250 
    251 	qlimit(cl->q_) = maxq;
    252 	qtype(cl->q_) = Q_DROPHEAD;
    253 	qlen(cl->q_) = 0;
    254 	cl->flags_ = flags;
    255 
    256 #if 1 /* minidle is also scaled in ALTQ */
    257 	cl->minidle_ = ((int64_t)minidle * (int64_t)psecPerByte) / 8;
    258 	if (cl->minidle_ > 0)
    259 		cl->minidle_ = 0;
    260 #else
    261 	cl->minidle_ = minidle;
    262 #endif
    263 	cl->maxidle_ = ((int64_t)maxidle * (int64_t)psecPerByte) / 8;
    264 	if (cl->maxidle_ == 0)
    265 		cl->maxidle_ = 1;
    266 #if 1 /* offtime is also scaled in ALTQ */
    267 	cl->avgidle_ = cl->maxidle_;
    268 	cl->offtime_ = (((int64_t)offtime * (int64_t)psecPerByte) / 8) >> RM_FILTER_GAIN;
    269 	if (cl->offtime_ == 0)
    270 		cl->offtime_ = 1;
    271 #else
    272 	cl->avgidle_ = 0;
    273 	cl->offtime_ = (offtime * nsecPerByte) / 8;
    274 #endif
    275 	cl->overlimit = action;
    276 
    277 #ifdef ALTQ_RED
    278 	if (flags & (RMCF_RED|RMCF_RIO)) {
    279 		int red_flags, red_pkttime;
    280 
    281 		red_flags = 0;
    282 		if (flags & RMCF_ECN)
    283 			red_flags |= REDF_ECN;
    284 		if (flags & RMCF_FLOWVALVE)
    285 			red_flags |= REDF_FLOWVALVE;
    286 #ifdef ALTQ_RIO
    287 		if (flags & RMCF_CLEARDSCP)
    288 			red_flags |= RIOF_CLEARDSCP;
    289 #endif
    290 		red_pkttime = PSEC_TO_NSEC(psecPerByte) * pktsize  / 1000;
    291 
    292 		if (flags & RMCF_RED) {
    293 			cl->red_ = red_alloc(0, 0,
    294 			    qlimit(cl->q_) * 10/100,
    295 			    qlimit(cl->q_) * 30/100,
    296 			    red_flags, red_pkttime);
    297 			if (cl->red_ != NULL)
    298 				qtype(cl->q_) = Q_RED;
    299 		}
    300 #ifdef ALTQ_RIO
    301 		else {
    302 			cl->red_ = (red_t *)rio_alloc(0, NULL,
    303 						      red_flags, red_pkttime);
    304 			if (cl->red_ != NULL)
    305 				qtype(cl->q_) = Q_RIO;
    306 		}
    307 #endif
    308 	}
    309 #endif /* ALTQ_RED */
    310 
    311 	/*
    312 	 * put the class into the class tree
    313 	 */
    314 	s = splnet();
    315 	if ((peer = ifd->active_[pri]) != NULL) {
    316 		/* find the last class at this pri */
    317 		cl->peer_ = peer;
    318 		while (peer->peer_ != ifd->active_[pri])
    319 			peer = peer->peer_;
    320 		peer->peer_ = cl;
    321 	} else {
    322 		ifd->active_[pri] = cl;
    323 		cl->peer_ = cl;
    324 	}
    325 
    326 	if (cl->parent_) {
    327 		cl->next_ = parent->children_;
    328 		parent->children_ = cl;
    329 		parent->leaf_ = 0;
    330 	}
    331 
    332 	/*
    333 	 * Compute the depth of this class and its ancestors in the class
    334 	 * hierarchy.
    335 	 */
    336 	rmc_depth_compute(cl);
    337 
    338 	/*
    339 	 * If CBQ's WRR is enabled, then initialize the class WRR state.
    340 	 */
    341 	if (ifd->wrr_) {
    342 		ifd->num_[pri]++;
    343 		ifd->alloc_[pri] += cl->allotment_;
    344 		rmc_wrr_set_weights(ifd);
    345 	}
    346 	splx(s);
    347 	return cl;
    348 }
    349 
    350 int
    351 rmc_modclass(struct rm_class *cl, uint64_t psecPerByte, int maxq, u_int maxidle,
    352     int minidle, u_int offtime, int pktsize)
    353 {
    354 	struct rm_ifdat	*ifd;
    355 	u_int		 old_allotment;
    356 	int		 s;
    357 
    358 	ifd = cl->ifdat_;
    359 	old_allotment = cl->allotment_;
    360 
    361 	s = splnet();
    362 	cl->allotment_ = (u_int)(RM_PS_PER_SEC / psecPerByte); /* Bytes per sec */
    363 	cl->qthresh_ = 0;
    364 	cl->ps_per_byte_ = psecPerByte;
    365 
    366 	qlimit(cl->q_) = maxq;
    367 
    368 #if 1 /* minidle is also scaled in ALTQ */
    369 	cl->minidle_ = ((int64_t)minidle * (int64_t)psecPerByte) / 8;
    370 	if (cl->minidle_ > 0)
    371 		cl->minidle_ = 0;
    372 #else
    373 	cl->minidle_ = minidle;
    374 #endif
    375 	cl->maxidle_ = ((int64_t)maxidle * (int64_t)psecPerByte) / 8;
    376 	if (cl->maxidle_ == 0)
    377 		cl->maxidle_ = 1;
    378 #if 1 /* offtime is also scaled in ALTQ */
    379 	cl->avgidle_ = cl->maxidle_;
    380 	cl->offtime_ = (((int64_t)offtime * (int64_t)psecPerByte) / 8) >> RM_FILTER_GAIN;
    381 	if (cl->offtime_ == 0)
    382 		cl->offtime_ = 1;
    383 #else
    384 	cl->avgidle_ = 0;
    385 	cl->offtime_ = (offtime * nsecPerByte) / 8;
    386 #endif
    387 
    388 	/*
    389 	 * If CBQ's WRR is enabled, then initialize the class WRR state.
    390 	 */
    391 	if (ifd->wrr_) {
    392 		ifd->alloc_[cl->pri_] += cl->allotment_ - old_allotment;
    393 		rmc_wrr_set_weights(ifd);
    394 	}
    395 	splx(s);
    396 	return 0;
    397 }
    398 
    399 /*
    400  * static void
    401  * rmc_wrr_set_weights(struct rm_ifdat *ifdat) - This function computes
    402  *	the appropriate run robin weights for the CBQ weighted round robin
    403  *	algorithm.
    404  *
    405  *	Returns: NONE
    406  */
    407 
    408 static void
    409 rmc_wrr_set_weights(struct rm_ifdat *ifd)
    410 {
    411 	int		i;
    412 	struct rm_class	*cl, *clh;
    413 
    414 	for (i = 0; i < RM_MAXPRIO; i++) {
    415 		/*
    416 		 * This is inverted from that of the simulator to
    417 		 * maintain precision.
    418 		 */
    419 		if (ifd->num_[i] == 0)
    420 			ifd->M_[i] = 0;
    421 		else
    422 			ifd->M_[i] = ifd->alloc_[i] /
    423 				(ifd->num_[i] * ifd->maxpkt_);
    424 		/*
    425 		 * Compute the weighted allotment for each class.
    426 		 * This takes the expensive div instruction out
    427 		 * of the main loop for the wrr scheduling path.
    428 		 * These only get recomputed when a class comes or
    429 		 * goes.
    430 		 */
    431 		if (ifd->active_[i] != NULL) {
    432 			clh = cl = ifd->active_[i];
    433 			do {
    434 				/* safe-guard for slow link or alloc_ == 0 */
    435 				if (ifd->M_[i] == 0)
    436 					cl->w_allotment_ = 0;
    437 				else
    438 					cl->w_allotment_ = cl->allotment_ /
    439 						ifd->M_[i];
    440 				cl = cl->peer_;
    441 			} while ((cl != NULL) && (cl != clh));
    442 		}
    443 	}
    444 }
    445 
    446 int
    447 rmc_get_weight(struct rm_ifdat *ifd, int pri)
    448 {
    449 	if ((pri >= 0) && (pri < RM_MAXPRIO))
    450 		return (ifd->M_[pri]);
    451 	else
    452 		return 0;
    453 }
    454 
    455 /*
    456  * static void
    457  * rmc_depth_compute(struct rm_class *cl) - This function computes the
    458  *	appropriate depth of class 'cl' and its ancestors.
    459  *
    460  *	Returns:	NONE
    461  */
    462 
    463 static void
    464 rmc_depth_compute(struct rm_class *cl)
    465 {
    466 	rm_class_t	*t = cl, *p;
    467 
    468 	/*
    469 	 * Recompute the depth for the branch of the tree.
    470 	 */
    471 	while (t != NULL) {
    472 		p = t->parent_;
    473 		if (p && (t->depth_ >= p->depth_)) {
    474 			p->depth_ = t->depth_ + 1;
    475 			t = p;
    476 		} else
    477 			t = NULL;
    478 	}
    479 }
    480 
    481 /*
    482  * static void
    483  * rmc_depth_recompute(struct rm_class *cl) - This function re-computes
    484  *	the depth of the tree after a class has been deleted.
    485  *
    486  *	Returns:	NONE
    487  */
    488 
    489 static void
    490 rmc_depth_recompute(rm_class_t *cl)
    491 {
    492 #if 1 /* ALTQ */
    493 	rm_class_t	*p, *t;
    494 
    495 	p = cl;
    496 	while (p != NULL) {
    497 		if ((t = p->children_) == NULL) {
    498 			p->depth_ = 0;
    499 		} else {
    500 			int cdepth = 0;
    501 
    502 			while (t != NULL) {
    503 				if (t->depth_ > cdepth)
    504 					cdepth = t->depth_;
    505 				t = t->next_;
    506 			}
    507 
    508 			if (p->depth_ == cdepth + 1)
    509 				/* no change to this parent */
    510 				return;
    511 
    512 			p->depth_ = cdepth + 1;
    513 		}
    514 
    515 		p = p->parent_;
    516 	}
    517 #else
    518 	rm_class_t	*t;
    519 
    520 	if (cl->depth_ >= 1) {
    521 		if (cl->children_ == NULL) {
    522 			cl->depth_ = 0;
    523 		} else if ((t = cl->children_) != NULL) {
    524 			while (t != NULL) {
    525 				if (t->children_ != NULL)
    526 					rmc_depth_recompute(t);
    527 				t = t->next_;
    528 			}
    529 		} else
    530 			rmc_depth_compute(cl);
    531 	}
    532 #endif
    533 }
    534 
    535 /*
    536  * void
    537  * rmc_delete_class(struct rm_ifdat *ifdat, struct rm_class *cl) - This
    538  *	function deletes a class from the link-sharing structure and frees
    539  *	all resources associated with the class.
    540  *
    541  *	Returns: NONE
    542  */
    543 
    544 void
    545 rmc_delete_class(struct rm_ifdat *ifd, struct rm_class *cl)
    546 {
    547 	struct rm_class	*p, *head, *previous;
    548 	int		 s;
    549 
    550 	ASSERT(cl->children_ == NULL);
    551 
    552 	if (cl->sleeping_)
    553 		CALLOUT_STOP(&cl->callout_);
    554 
    555 	s = splnet();
    556 	/*
    557 	 * Free packets in the packet queue.
    558 	 * XXX - this may not be a desired behavior.  Packets should be
    559 	 *		re-queued.
    560 	 */
    561 	rmc_dropall(cl);
    562 
    563 	/*
    564 	 * If the class has a parent, then remove the class from the
    565 	 * class from the parent's children chain.
    566 	 */
    567 	if (cl->parent_ != NULL) {
    568 		head = cl->parent_->children_;
    569 		p = previous = head;
    570 		if (head->next_ == NULL) {
    571 			ASSERT(head == cl);
    572 			cl->parent_->children_ = NULL;
    573 			cl->parent_->leaf_ = 1;
    574 		} else while (p != NULL) {
    575 			if (p == cl) {
    576 				if (cl == head)
    577 					cl->parent_->children_ = cl->next_;
    578 				else
    579 					previous->next_ = cl->next_;
    580 				cl->next_ = NULL;
    581 				p = NULL;
    582 			} else {
    583 				previous = p;
    584 				p = p->next_;
    585 			}
    586 		}
    587 	}
    588 
    589 	/*
    590 	 * Delete class from class priority peer list.
    591 	 */
    592 	if ((p = ifd->active_[cl->pri_]) != NULL) {
    593 		/*
    594 		 * If there is more than one member of this priority
    595 		 * level, then look for class(cl) in the priority level.
    596 		 */
    597 		if (p != p->peer_) {
    598 			while (p->peer_ != cl)
    599 				p = p->peer_;
    600 			p->peer_ = cl->peer_;
    601 
    602 			if (ifd->active_[cl->pri_] == cl)
    603 				ifd->active_[cl->pri_] = cl->peer_;
    604 		} else {
    605 			ASSERT(p == cl);
    606 			ifd->active_[cl->pri_] = NULL;
    607 		}
    608 	}
    609 
    610 	/*
    611 	 * Recompute the WRR weights.
    612 	 */
    613 	if (ifd->wrr_) {
    614 		ifd->alloc_[cl->pri_] -= cl->allotment_;
    615 		ifd->num_[cl->pri_]--;
    616 		rmc_wrr_set_weights(ifd);
    617 	}
    618 
    619 	/*
    620 	 * Re-compute the depth of the tree.
    621 	 */
    622 #if 1 /* ALTQ */
    623 	rmc_depth_recompute(cl->parent_);
    624 #else
    625 	rmc_depth_recompute(ifd->root_);
    626 #endif
    627 
    628 	splx(s);
    629 
    630 	/*
    631 	 * Free the class structure.
    632 	 */
    633 	if (cl->red_ != NULL) {
    634 #ifdef ALTQ_RIO
    635 		if (q_is_rio(cl->q_))
    636 			rio_destroy((rio_t *)cl->red_);
    637 #endif
    638 #ifdef ALTQ_RED
    639 		if (q_is_red(cl->q_))
    640 			red_destroy(cl->red_);
    641 #endif
    642 	}
    643 	free(cl->q_, M_DEVBUF);
    644 	free(cl, M_DEVBUF);
    645 }
    646 
    647 
    648 /*
    649  * int
    650  * rmc_init(...) - Initialize the resource management data structures
    651  *	associated with the output portion of interface 'ifp'.  'ifd' is
    652  *	where the structures will be built (for backwards compatibility, the
    653  *	structures aren't kept in the ifnet struct).  'nsecPerByte'
    654  *	gives the link speed (inverse of bandwidth) in nanoseconds/byte.
    655  *	'restart' is the driver-specific routine that the generic 'delay
    656  *	until under limit' action will call to restart output.  `maxq'
    657  *	is the queue size of the 'link' & 'default' classes.  'maxqueued'
    658  *	is the maximum number of packets that the resource management
    659  *	code will allow to be queued 'downstream' (this is typically 1).
    660  *
    661  *	Returns:	0 on success
    662  */
    663 
    664 int
    665 rmc_init(struct ifaltq *ifq, struct rm_ifdat *ifd, uint64_t psecPerByte,
    666     void (*restart)(struct ifaltq *), int maxq, int maxqueued, u_int maxidle,
    667     int minidle, u_int offtime, int flags)
    668 {
    669 	int i, mtu;
    670 
    671 	/*
    672 	 * Initialize the CBQ tracing/debug facility.
    673 	 */
    674 	CBQTRACEINIT();
    675 
    676 	mtu = ifq->altq_ifp->if_mtu;
    677 	if (mtu < 1) {
    678 		printf("altq: %s: invalid MTU (interface not initialized?)\n",
    679 		    ifq->altq_ifp->if_xname);
    680 		return EINVAL;
    681 	}
    682 
    683 	(void)memset((char *)ifd, 0, sizeof (*ifd));
    684 	ifd->ifq_ = ifq;
    685 	ifd->restart = restart;
    686 	ifd->maxqueued_ = maxqueued;
    687 	ifd->ps_per_byte_ = psecPerByte;
    688 	ifd->maxpkt_ = mtu;
    689 	ifd->wrr_ = (flags & RMCF_WRR) ? 1 : 0;
    690 	ifd->efficient_ = (flags & RMCF_EFFICIENT) ? 1 : 0;
    691 #if 1
    692 	ifd->maxiftime_ = mtu * psecPerByte / 1000 / 1000 * 16;
    693 	if ((int64_t)mtu * psecPerByte > (int64_t)10 * 1000000000)
    694 		ifd->maxiftime_ /= 4;
    695 #endif
    696 
    697 	reset_cutoff(ifd);
    698 	CBQTRACE(rmc_init, 'INIT', ifd->cutoff_);
    699 
    700 	/*
    701 	 * Initialize the CBQ's WRR state.
    702 	 */
    703 	for (i = 0; i < RM_MAXPRIO; i++) {
    704 		ifd->alloc_[i] = 0;
    705 		ifd->M_[i] = 0;
    706 		ifd->num_[i] = 0;
    707 		ifd->na_[i] = 0;
    708 		ifd->active_[i] = NULL;
    709 	}
    710 
    711 	/*
    712 	 * Initialize current packet state.
    713 	 */
    714 	ifd->qi_ = 0;
    715 	ifd->qo_ = 0;
    716 	for (i = 0; i < RM_MAXQUEUED; i++) {
    717 		ifd->class_[i] = NULL;
    718 		ifd->curlen_[i] = 0;
    719 		ifd->borrowed_[i] = NULL;
    720 	}
    721 
    722 	/*
    723 	 * Create the root class of the link-sharing structure.
    724 	 */
    725 	if ((ifd->root_ = rmc_newclass(0, ifd,
    726 				       psecPerByte,
    727 				       rmc_root_overlimit, maxq, 0, 0,
    728 				       maxidle, minidle, offtime,
    729 				       0, 0)) == NULL) {
    730 		printf("rmc_init: root class not allocated\n");
    731 		return ENOMEM;
    732 	}
    733 	ifd->root_->depth_ = 0;
    734 
    735 	return 0;
    736 }
    737 
    738 /*
    739  * void
    740  * rmc_queue_packet(struct rm_class *cl, mbuf_t *m) - Add packet given by
    741  *	mbuf 'm' to queue for resource class 'cl'.  This routine is called
    742  *	by a driver's if_output routine.  This routine must be called with
    743  *	output packet completion interrupts locked out (to avoid racing with
    744  *	rmc_dequeue_next).
    745  *
    746  *	Returns:	0 on successful queueing
    747  *			-1 when packet drop occurs
    748  */
    749 int
    750 rmc_queue_packet(struct rm_class *cl, mbuf_t *m)
    751 {
    752 	struct timespec	 now;
    753 	struct rm_ifdat *ifd = cl->ifdat_;
    754 	int		 cpri = cl->pri_;
    755 	int		 is_empty = qempty(cl->q_);
    756 
    757 	RM_GETTIME(now);
    758 	if (ifd->cutoff_ > 0) {
    759 		if (TS_LT(&cl->undertime_, &now)) {
    760 			if (ifd->cutoff_ > cl->depth_)
    761 				ifd->cutoff_ = cl->depth_;
    762 			CBQTRACE(rmc_queue_packet, 'ffoc', cl->depth_);
    763 		}
    764 #if 1 /* ALTQ */
    765 		else {
    766 			/*
    767 			 * the class is overlimit. if the class has
    768 			 * underlimit ancestors, set cutoff to the lowest
    769 			 * depth among them.
    770 			 */
    771 			struct rm_class *borrow = cl->borrow_;
    772 
    773 			while (borrow != NULL &&
    774 			       borrow->depth_ < ifd->cutoff_) {
    775 				if (TS_LT(&borrow->undertime_, &now)) {
    776 					ifd->cutoff_ = borrow->depth_;
    777 					CBQTRACE(rmc_queue_packet, 'ffob', ifd->cutoff_);
    778 					break;
    779 				}
    780 				borrow = borrow->borrow_;
    781 			}
    782 		}
    783 #else /* !ALTQ */
    784 		else if ((ifd->cutoff_ > 1) && cl->borrow_) {
    785 			if (TS_LT(&cl->borrow_->undertime_, &now)) {
    786 				ifd->cutoff_ = cl->borrow_->depth_;
    787 				CBQTRACE(rmc_queue_packet, 'ffob',
    788 					 cl->borrow_->depth_);
    789 			}
    790 		}
    791 #endif /* !ALTQ */
    792 	}
    793 
    794 	if (_rmc_addq(cl, m) < 0)
    795 		/* failed */
    796 		return -1;
    797 
    798 	if (is_empty) {
    799 		CBQTRACE(rmc_queue_packet, 'ytpe', cl->stats_.handle);
    800 		ifd->na_[cpri]++;
    801 	}
    802 
    803 	if (qlen(cl->q_) > qlimit(cl->q_)) {
    804 		/* note: qlimit can be set to 0 or 1 */
    805 		rmc_drop_action(cl);
    806 		return -1;
    807 	}
    808 	return 0;
    809 }
    810 
    811 /*
    812  * void
    813  * rmc_tl_satisfied(struct rm_ifdat *ifd, struct timespec *now) - Check all
    814  *	classes to see if there are satified.
    815  */
    816 
    817 static void
    818 rmc_tl_satisfied(struct rm_ifdat *ifd, struct timespec *now)
    819 {
    820 	int		 i;
    821 	rm_class_t	*p, *bp;
    822 
    823 	for (i = RM_MAXPRIO - 1; i >= 0; i--) {
    824 		if ((bp = ifd->active_[i]) != NULL) {
    825 			p = bp;
    826 			do {
    827 				if (!rmc_satisfied(p, now)) {
    828 					ifd->cutoff_ = p->depth_;
    829 					return;
    830 				}
    831 				p = p->peer_;
    832 			} while (p != bp);
    833 		}
    834 	}
    835 
    836 	reset_cutoff(ifd);
    837 }
    838 
    839 /*
    840  * rmc_satisfied - Return 1 of the class is satisfied.  O, otherwise.
    841  */
    842 
    843 static int
    844 rmc_satisfied(struct rm_class *cl, struct timespec *now)
    845 {
    846 	rm_class_t	*p;
    847 
    848 	if (cl == NULL)
    849 		return 1;
    850 	if (TS_LT(now, &cl->undertime_))
    851 		return 1;
    852 	if (cl->depth_ == 0) {
    853 		if (!cl->sleeping_ && (qlen(cl->q_) > cl->qthresh_))
    854 			return 0;
    855 		else
    856 			return 1;
    857 	}
    858 	if (cl->children_ != NULL) {
    859 		p = cl->children_;
    860 		while (p != NULL) {
    861 			if (!rmc_satisfied(p, now))
    862 				return 0;
    863 			p = p->next_;
    864 		}
    865 	}
    866 
    867 	return 1;
    868 }
    869 
    870 /*
    871  * Return 1 if class 'cl' is under limit or can borrow from a parent,
    872  * 0 if overlimit.  As a side-effect, this routine will invoke the
    873  * class overlimit action if the class if overlimit.
    874  */
    875 
    876 static int
    877 rmc_under_limit(struct rm_class *cl, struct timespec *now)
    878 {
    879 	rm_class_t	*p = cl;
    880 	rm_class_t	*top;
    881 	struct rm_ifdat	*ifd = cl->ifdat_;
    882 	int sleeping = cl->sleeping_;
    883 
    884 	ifd->borrowed_[ifd->qi_] = NULL;
    885 	/*
    886 	 * If cl is the root class, then always return that it is
    887 	 * underlimit.  Otherwise, check to see if the class is underlimit.
    888 	 */
    889 	if (cl->parent_ == NULL)
    890 		return 1;
    891 
    892 	if (!TS_LT(now, &cl->undertime_)) {
    893 		/* Fast path: the given class is allowed to send packets */
    894 		if (sleeping) {
    895 			CALLOUT_STOP(&cl->callout_);
    896 			cl->sleeping_ = 0;
    897 			cl->undertime_.tv_sec = 0;
    898 		}
    899 		return 1;
    900 	}
    901 
    902 	top = NULL;
    903 	do {
    904 		if (((cl = cl->borrow_) == NULL) ||
    905 		    (cl->depth_ > ifd->cutoff_)) {
    906 			/* No need to call the delay action */
    907 			if (sleeping)
    908 				return 0;
    909 #ifdef ADJUST_CUTOFF
    910 			if (cl != NULL)
    911 				/* cutoff is taking effect, just
    912 				   return false without calling
    913 				   the delay action. */
    914 				return 0;
    915 #endif
    916 #ifdef BORROW_OFFTIME
    917 			/*
    918 			 * check if the class can borrow offtime too.
    919 			 * borrow offtime from the top of the borrow
    920 			 * chain if the top class is not overloaded.
    921 			 */
    922 			if (cl != NULL) {
    923 				/* cutoff is taking effect, use this class as top. */
    924 				top = cl;
    925 				CBQTRACE(rmc_under_limit, 'ffou', ifd->cutoff_);
    926 			}
    927 			if (top != NULL && top->avgidle_ == top->minidle_)
    928 				top = NULL;
    929 			p->overtime_ = *now;
    930 			(p->overlimit)(p, top);
    931 #else
    932 			p->overtime_ = *now;
    933 			(p->overlimit)(p, NULL);
    934 #endif
    935 			return 0;
    936 		}
    937 		top = cl;
    938 	} while (cl->undertime_.tv_sec && TS_LT(now, &cl->undertime_));
    939 
    940 	if (cl != p)
    941 		ifd->borrowed_[ifd->qi_] = cl;
    942 	return 1;
    943 }
    944 
    945 /*
    946  * _rmc_wrr_dequeue_next() - This is scheduler for WRR as opposed to
    947  *	Packet-by-packet round robin.
    948  *
    949  * The heart of the weighted round-robin scheduler, which decides which
    950  * class next gets to send a packet.  Highest priority first, then
    951  * weighted round-robin within priorites.
    952  *
    953  * Each able-to-send class gets to send until its byte allocation is
    954  * exhausted.  Thus, the active pointer is only changed after a class has
    955  * exhausted its allocation.
    956  *
    957  * If the scheduler finds no class that is underlimit or able to borrow,
    958  * then the first class found that had a nonzero queue and is allowed to
    959  * borrow gets to send.
    960  */
    961 
    962 static mbuf_t *
    963 _rmc_wrr_dequeue_next(struct rm_ifdat *ifd, int op)
    964 {
    965 	struct rm_class	*cl = NULL, *first = NULL;
    966 	u_int		 deficit;
    967 	int		 cpri;
    968 	mbuf_t		*m;
    969 	struct timespec	 now;
    970 
    971 	RM_GETTIME(now);
    972 
    973 	/*
    974 	 * if the driver polls the top of the queue and then removes
    975 	 * the polled packet, we must return the same packet.
    976 	 */
    977 	if (op == ALTDQ_REMOVE && ifd->pollcache_) {
    978 		cl = ifd->pollcache_;
    979 		cpri = cl->pri_;
    980 		if (ifd->efficient_) {
    981 			/* check if this class is overlimit */
    982 			if (cl->undertime_.tv_sec != 0 &&
    983 			    rmc_under_limit(cl, &now) == 0)
    984 				first = cl;
    985 		}
    986 		ifd->pollcache_ = NULL;
    987 		goto _wrr_out;
    988 	}
    989 	else {
    990 		/* mode == ALTDQ_POLL || pollcache == NULL */
    991 		ifd->pollcache_ = NULL;
    992 		ifd->borrowed_[ifd->qi_] = NULL;
    993 	}
    994 #ifdef ADJUST_CUTOFF
    995  _again:
    996 #endif
    997 	for (cpri = RM_MAXPRIO - 1; cpri >= 0; cpri--) {
    998 		if (ifd->na_[cpri] == 0)
    999 			continue;
   1000 		deficit = 0;
   1001 		/*
   1002 		 * Loop through twice for a priority level, if some class
   1003 		 * was unable to send a packet the first round because
   1004 		 * of the weighted round-robin mechanism.
   1005 		 * During the second loop at this level, deficit==2.
   1006 		 * (This second loop is not needed if for every class,
   1007 		 * "M[cl->pri_])" times "cl->allotment" is greater than
   1008 		 * the byte size for the largest packet in the class.)
   1009 		 */
   1010  _wrr_loop:
   1011 		cl = ifd->active_[cpri];
   1012 		ASSERT(cl != NULL);
   1013 		do {
   1014 			if ((deficit < 2) && (cl->bytes_alloc_ <= 0))
   1015 				cl->bytes_alloc_ += cl->w_allotment_;
   1016 			if (!qempty(cl->q_)) {
   1017 				if ((cl->undertime_.tv_sec == 0) ||
   1018 				    rmc_under_limit(cl, &now)) {
   1019 					if (cl->bytes_alloc_ > 0 || deficit > 1)
   1020 						goto _wrr_out;
   1021 
   1022 					/* underlimit but no alloc */
   1023 					deficit = 1;
   1024 #if 1
   1025 					ifd->borrowed_[ifd->qi_] = NULL;
   1026 #endif
   1027 				}
   1028 				else if (first == NULL && cl->borrow_ != NULL)
   1029 					first = cl; /* borrowing candidate */
   1030 			}
   1031 
   1032 			cl->bytes_alloc_ = 0;
   1033 			cl = cl->peer_;
   1034 		} while (cl != ifd->active_[cpri]);
   1035 
   1036 		if (deficit == 1) {
   1037 			/* first loop found an underlimit class with deficit */
   1038 			/* Loop on same priority level, with new deficit.  */
   1039 			deficit = 2;
   1040 			goto _wrr_loop;
   1041 		}
   1042 	}
   1043 
   1044 #ifdef ADJUST_CUTOFF
   1045 	/*
   1046 	 * no underlimit class found.  if cutoff is taking effect,
   1047 	 * increase cutoff and try again.
   1048 	 */
   1049 	if (first != NULL && ifd->cutoff_ < ifd->root_->depth_) {
   1050 		ifd->cutoff_++;
   1051 		CBQTRACE(_rmc_wrr_dequeue_next, 'ojda', ifd->cutoff_);
   1052 		goto _again;
   1053 	}
   1054 #endif /* ADJUST_CUTOFF */
   1055 	/*
   1056 	 * If LINK_EFFICIENCY is turned on, then the first overlimit
   1057 	 * class we encounter will send a packet if all the classes
   1058 	 * of the link-sharing structure are overlimit.
   1059 	 */
   1060 	reset_cutoff(ifd);
   1061 	CBQTRACE(_rmc_wrr_dequeue_next, 'otsr', ifd->cutoff_);
   1062 
   1063 	if (!ifd->efficient_ || first == NULL)
   1064 		return NULL;
   1065 
   1066 	cl = first;
   1067 	cpri = cl->pri_;
   1068 #if 0	/* too time-consuming for nothing */
   1069 	if (cl->sleeping_)
   1070 		CALLOUT_STOP(&cl->callout_);
   1071 	cl->sleeping_ = 0;
   1072 	cl->undertime_.tv_sec = 0;
   1073 #endif
   1074 	ifd->borrowed_[ifd->qi_] = cl->borrow_;
   1075 	ifd->cutoff_ = cl->borrow_->depth_;
   1076 
   1077 	/*
   1078 	 * Deque the packet and do the book keeping...
   1079 	 */
   1080  _wrr_out:
   1081 	if (op == ALTDQ_REMOVE) {
   1082 		m = _rmc_getq(cl);
   1083 		if (m == NULL)
   1084 			panic("_rmc_wrr_dequeue_next");
   1085 		if (qempty(cl->q_))
   1086 			ifd->na_[cpri]--;
   1087 
   1088 		/*
   1089 		 * Update class statistics and link data.
   1090 		 */
   1091 		if (cl->bytes_alloc_ > 0)
   1092 			cl->bytes_alloc_ -= m_pktlen(m);
   1093 
   1094 		if ((cl->bytes_alloc_ <= 0) || first == cl)
   1095 			ifd->active_[cl->pri_] = cl->peer_;
   1096 		else
   1097 			ifd->active_[cl->pri_] = cl;
   1098 
   1099 		ifd->class_[ifd->qi_] = cl;
   1100 		ifd->curlen_[ifd->qi_] = m_pktlen(m);
   1101 		ifd->now_[ifd->qi_] = now;
   1102 		ifd->qi_ = (ifd->qi_ + 1) % ifd->maxqueued_;
   1103 		ifd->queued_++;
   1104 	} else {
   1105 		/* mode == ALTDQ_PPOLL */
   1106 		m = _rmc_pollq(cl);
   1107 		ifd->pollcache_ = cl;
   1108 	}
   1109 	return m;
   1110 }
   1111 
   1112 /*
   1113  * Dequeue & return next packet from the highest priority class that
   1114  * has a packet to send & has enough allocation to send it.  This
   1115  * routine is called by a driver whenever it needs a new packet to
   1116  * output.
   1117  */
   1118 static mbuf_t *
   1119 _rmc_prr_dequeue_next(struct rm_ifdat *ifd, int op)
   1120 {
   1121 	mbuf_t		*m;
   1122 	int		 cpri;
   1123 	struct rm_class	*cl, *first = NULL;
   1124 	struct timespec	 now;
   1125 
   1126 	RM_GETTIME(now);
   1127 
   1128 	/*
   1129 	 * if the driver polls the top of the queue and then removes
   1130 	 * the polled packet, we must return the same packet.
   1131 	 */
   1132 	if (op == ALTDQ_REMOVE && ifd->pollcache_) {
   1133 		cl = ifd->pollcache_;
   1134 		cpri = cl->pri_;
   1135 		ifd->pollcache_ = NULL;
   1136 		goto _prr_out;
   1137 	} else {
   1138 		/* mode == ALTDQ_POLL || pollcache == NULL */
   1139 		ifd->pollcache_ = NULL;
   1140 		ifd->borrowed_[ifd->qi_] = NULL;
   1141 	}
   1142 #ifdef ADJUST_CUTOFF
   1143  _again:
   1144 #endif
   1145 	for (cpri = RM_MAXPRIO - 1; cpri >= 0; cpri--) {
   1146 		if (ifd->na_[cpri] == 0)
   1147 			continue;
   1148 		cl = ifd->active_[cpri];
   1149 		ASSERT(cl != NULL);
   1150 		do {
   1151 			if (!qempty(cl->q_)) {
   1152 				if ((cl->undertime_.tv_sec == 0) ||
   1153 				    rmc_under_limit(cl, &now))
   1154 					goto _prr_out;
   1155 				if (first == NULL && cl->borrow_ != NULL)
   1156 					first = cl;
   1157 			}
   1158 			cl = cl->peer_;
   1159 		} while (cl != ifd->active_[cpri]);
   1160 	}
   1161 
   1162 #ifdef ADJUST_CUTOFF
   1163 	/*
   1164 	 * no underlimit class found.  if cutoff is taking effect, increase
   1165 	 * cutoff and try again.
   1166 	 */
   1167 	if (first != NULL && ifd->cutoff_ < ifd->root_->depth_) {
   1168 		ifd->cutoff_++;
   1169 		goto _again;
   1170 	}
   1171 #endif /* ADJUST_CUTOFF */
   1172 	/*
   1173 	 * If LINK_EFFICIENCY is turned on, then the first overlimit
   1174 	 * class we encounter will send a packet if all the classes
   1175 	 * of the link-sharing structure are overlimit.
   1176 	 */
   1177 	reset_cutoff(ifd);
   1178 	if (!ifd->efficient_ || first == NULL)
   1179 		return NULL;
   1180 
   1181 	cl = first;
   1182 	cpri = cl->pri_;
   1183 #if 0	/* too time-consuming for nothing */
   1184 	if (cl->sleeping_)
   1185 		CALLOUT_STOP(&cl->callout_);
   1186 	cl->sleeping_ = 0;
   1187 	cl->undertime_.tv_sec = 0;
   1188 #endif
   1189 	ifd->borrowed_[ifd->qi_] = cl->borrow_;
   1190 	ifd->cutoff_ = cl->borrow_->depth_;
   1191 
   1192 	/*
   1193 	 * Deque the packet and do the book keeping...
   1194 	 */
   1195  _prr_out:
   1196 	if (op == ALTDQ_REMOVE) {
   1197 		m = _rmc_getq(cl);
   1198 		if (m == NULL)
   1199 			panic("_rmc_prr_dequeue_next");
   1200 		if (qempty(cl->q_))
   1201 			ifd->na_[cpri]--;
   1202 
   1203 		ifd->active_[cpri] = cl->peer_;
   1204 
   1205 		ifd->class_[ifd->qi_] = cl;
   1206 		ifd->curlen_[ifd->qi_] = m_pktlen(m);
   1207 		ifd->now_[ifd->qi_] = now;
   1208 		ifd->qi_ = (ifd->qi_ + 1) % ifd->maxqueued_;
   1209 		ifd->queued_++;
   1210 	} else {
   1211 		/* mode == ALTDQ_POLL */
   1212 		m = _rmc_pollq(cl);
   1213 		ifd->pollcache_ = cl;
   1214 	}
   1215 	return m;
   1216 }
   1217 
   1218 /*
   1219  * mbuf_t *
   1220  * rmc_dequeue_next(struct rm_ifdat *ifd, struct timespec *now) - this function
   1221  *	is invoked by the packet driver to get the next packet to be
   1222  *	dequeued and output on the link.  If WRR is enabled, then the
   1223  *	WRR dequeue next routine will determine the next packet to sent.
   1224  *	Otherwise, packet-by-packet round robin is invoked.
   1225  *
   1226  *	Returns:	NULL, if a packet is not available or if all
   1227  *			classes are overlimit.
   1228  *
   1229  *			Otherwise, Pointer to the next packet.
   1230  */
   1231 
   1232 mbuf_t *
   1233 rmc_dequeue_next(struct rm_ifdat *ifd, int mode)
   1234 {
   1235 	if (ifd->queued_ >= ifd->maxqueued_)
   1236 		return NULL;
   1237 	else if (ifd->wrr_)
   1238 		return (_rmc_wrr_dequeue_next(ifd, mode));
   1239 	else
   1240 		return (_rmc_prr_dequeue_next(ifd, mode));
   1241 }
   1242 
   1243 /*
   1244  * Update the utilization estimate for the packet that just completed.
   1245  * The packet's class & the parent(s) of that class all get their
   1246  * estimators updated.  This routine is called by the driver's output-
   1247  * packet-completion interrupt service routine.
   1248  */
   1249 
   1250 /*
   1251  * a macro to approximate "divide by 1000" that gives 0.000999,
   1252  * if a value has enough effective digits.
   1253  * (on pentium, mul takes 9 cycles but div takes 46!)
   1254  */
   1255 #define	NSEC_TO_USEC(t)	(((t) >> 10) + ((t) >> 16) + ((t) >> 17))
   1256 /* Don't worry.  Recent compilers don't use div. */
   1257 #define	PSEC_TO_USEC(t)	((t) / 1000 / 1000)
   1258 void
   1259 rmc_update_class_util(struct rm_ifdat *ifd)
   1260 {
   1261 	int64_t		 idle, avgidle, pktlen;
   1262 	int64_t		 pkt_time;
   1263 	int64_t		 tidle;
   1264 	rm_class_t	*cl, *cl0, *borrowed;
   1265 	rm_class_t	*borrows;
   1266 	struct timespec	*nowp;
   1267 
   1268 	/*
   1269 	 * Get the most recent completed class.
   1270 	 */
   1271 	if ((cl = ifd->class_[ifd->qo_]) == NULL)
   1272 		return;
   1273 
   1274 	cl0 = cl;
   1275 	pktlen = (int64_t)ifd->curlen_[ifd->qo_];
   1276 	borrowed = ifd->borrowed_[ifd->qo_];
   1277 	borrows = borrowed;
   1278 
   1279 	PKTCNTR_ADD(&cl->stats_.xmit_cnt, pktlen);
   1280 
   1281 	/*
   1282 	 * Run estimator on class and its ancestors.
   1283 	 */
   1284 	/*
   1285 	 * rm_update_class_util is designed to be called when the
   1286 	 * transfer is completed from a xmit complete interrupt,
   1287 	 * but most drivers don't implement an upcall for that.
   1288 	 * so, just use estimated completion time.
   1289 	 * as a result, ifd->qi_ and ifd->qo_ are always synced.
   1290 	 */
   1291 	nowp = &ifd->now_[ifd->qo_];
   1292 	/* get pkt_time (for link) in usec */
   1293 #if 1  /* use approximation */
   1294 	pkt_time = (int64_t)ifd->curlen_[ifd->qo_] * (int64_t)ifd->ps_per_byte_;
   1295 	pkt_time = PSEC_TO_NSEC(pkt_time);
   1296 #else
   1297 	pkt_time = ifd->curlen_[ifd->qo_] * ifd->ns_per_byte_ / 1000;
   1298 #endif
   1299 	if (ifd->ifq_->altq_ifp->if_type == IFT_PPP) {
   1300 		if (TS_LT(nowp, &ifd->ifnow_)) {
   1301 			int iftime;
   1302 
   1303 			/*
   1304 			 * make sure the estimated completion time does not go
   1305 			 * too far.  it can happen when the link layer supports
   1306 			 * data compression or the interface speed is set to
   1307 			 * a much lower value.
   1308 			 */
   1309 			TS_DELTA(&ifd->ifnow_, nowp, iftime);
   1310 			if (iftime+pkt_time < ifd->maxiftime_) {
   1311 				TS_ADD_DELTA(&ifd->ifnow_, pkt_time, &ifd->ifnow_);
   1312 			} else {
   1313 				TS_ADD_DELTA(nowp, ifd->maxiftime_, &ifd->ifnow_);
   1314 			}
   1315 		} else {
   1316 			TS_ADD_DELTA(nowp, pkt_time, &ifd->ifnow_);
   1317 		}
   1318 	} else {
   1319 		if (TS_LT(nowp, &ifd->ifnow_)) {
   1320 			TS_ADD_DELTA(&ifd->ifnow_, pkt_time, &ifd->ifnow_);
   1321 		} else {
   1322 			TS_ADD_DELTA(nowp, pkt_time, &ifd->ifnow_);
   1323 		}
   1324 	}
   1325 
   1326 	while (cl != NULL) {
   1327 		TS_DELTA(&ifd->ifnow_, &cl->last_, idle);
   1328 		if (idle >= 2000000000)
   1329 			/*
   1330 			 * this class is idle enough, reset avgidle.
   1331 			 * (TS_DELTA returns 2000000000 ns when delta is large.)
   1332 			 */
   1333 			cl->avgidle_ = cl->maxidle_;
   1334 
   1335 		/* get pkt_time (for class) in usec */
   1336 #if 1  /* use approximation */
   1337 		pkt_time = pktlen * (int64_t)cl->ps_per_byte_;
   1338 		pkt_time = PSEC_TO_NSEC(pkt_time);
   1339 #else
   1340 		pkt_time = pktlen * cl->ns_per_byte_ / 1000;
   1341 #endif
   1342 		idle -= pkt_time;
   1343 
   1344 		avgidle = cl->avgidle_;
   1345 		avgidle += idle - (avgidle >> RM_FILTER_GAIN);
   1346 		cl->avgidle_ = avgidle;
   1347 
   1348 		/* Are we overlimit ? */
   1349 		if (avgidle <= 0) {
   1350 			CBQTRACE(rmc_update_class_util, 'milo', cl->stats_.handle);
   1351 #if 1 /* ALTQ */
   1352 			/*
   1353 			 * need some lower bound for avgidle, otherwise
   1354 			 * a borrowing class gets unbounded penalty.
   1355 			 */
   1356 			if (avgidle < cl->minidle_)
   1357 				avgidle = cl->avgidle_ = cl->minidle_;
   1358 #endif
   1359 			/* set next idle to make avgidle 0 */
   1360 			tidle = pkt_time +
   1361 				(((1 - RM_POWER) * avgidle) >> RM_FILTER_GAIN);
   1362 			TS_ADD_DELTA(nowp, tidle, &cl->undertime_);
   1363 			++cl->stats_.over;
   1364 		} else {
   1365 			cl->avgidle_ =
   1366 			    (avgidle > cl->maxidle_) ? cl->maxidle_ : avgidle;
   1367 			cl->undertime_.tv_sec = 0;
   1368 			if (cl->sleeping_) {
   1369 				CALLOUT_STOP(&cl->callout_);
   1370 				cl->sleeping_ = 0;
   1371 			}
   1372 		}
   1373 
   1374 		if (borrows != NULL) {
   1375 			if (borrows != cl)
   1376 				++cl->stats_.borrows;
   1377 			else
   1378 				borrows = NULL;
   1379 		}
   1380 		cl->last_ = ifd->ifnow_;
   1381 		cl->last_pkttime_ = pkt_time;
   1382 
   1383 #if 1
   1384 		if (cl->parent_ == NULL && cl != cl0) {
   1385 			/* take stats of root class */
   1386 			PKTCNTR_ADD(&cl->stats_.xmit_cnt, pktlen);
   1387 		}
   1388 #endif
   1389 
   1390 		cl = cl->parent_;
   1391 	}
   1392 
   1393 	/*
   1394 	 * Check to see if cutoff needs to set to a new level.
   1395 	 */
   1396 	cl = ifd->class_[ifd->qo_];
   1397 	if (borrowed && (ifd->cutoff_ >= borrowed->depth_)) {
   1398 #if 1 /* ALTQ */
   1399 		if ((qlen(cl->q_) <= 0) || TS_LT(nowp, &borrowed->undertime_)) {
   1400 			rmc_tl_satisfied(ifd, nowp);
   1401 			CBQTRACE(rmc_update_class_util, 'broe', ifd->cutoff_);
   1402 		} else {
   1403 			ifd->cutoff_ = borrowed->depth_;
   1404 			CBQTRACE(rmc_update_class_util, 'ffob', borrowed->depth_);
   1405 		}
   1406 #else /* !ALTQ */
   1407 		if ((qlen(cl->q_) <= 1) || TS_LT(&now, &borrowed->undertime_)) {
   1408 			reset_cutoff(ifd);
   1409 #ifdef notdef
   1410 			rmc_tl_satisfied(ifd, &now);
   1411 #endif
   1412 			CBQTRACE(rmc_update_class_util, 'broe', ifd->cutoff_);
   1413 		} else {
   1414 			ifd->cutoff_ = borrowed->depth_;
   1415 			CBQTRACE(rmc_update_class_util, 'ffob', borrowed->depth_);
   1416 		}
   1417 #endif /* !ALTQ */
   1418 	}
   1419 
   1420 	/*
   1421 	 * Release class slot
   1422 	 */
   1423 	ifd->borrowed_[ifd->qo_] = NULL;
   1424 	ifd->class_[ifd->qo_] = NULL;
   1425 	ifd->qo_ = (ifd->qo_ + 1) % ifd->maxqueued_;
   1426 	ifd->queued_--;
   1427 }
   1428 
   1429 /*
   1430  * void
   1431  * rmc_drop_action(struct rm_class *cl) - Generic (not protocol-specific)
   1432  *	over-limit action routines.  These get invoked by rmc_under_limit()
   1433  *	if a class with packets to send if over its bandwidth limit & can't
   1434  *	borrow from a parent class.
   1435  *
   1436  *	Returns: NONE
   1437  */
   1438 
   1439 static void
   1440 rmc_drop_action(struct rm_class *cl)
   1441 {
   1442 	struct rm_ifdat	*ifd = cl->ifdat_;
   1443 
   1444 	ASSERT(qlen(cl->q_) > 0);
   1445 	_rmc_dropq(cl);
   1446 	if (qempty(cl->q_))
   1447 		ifd->na_[cl->pri_]--;
   1448 }
   1449 
   1450 void
   1451 rmc_dropall(struct rm_class *cl)
   1452 {
   1453 	struct rm_ifdat	*ifd = cl->ifdat_;
   1454 
   1455 	if (!qempty(cl->q_)) {
   1456 		_flushq(cl->q_);
   1457 
   1458 		ifd->na_[cl->pri_]--;
   1459 	}
   1460 }
   1461 
   1462 #if (__FreeBSD_version > 300000)
   1463 static int tvhzto(struct timeval *);
   1464 
   1465 static int
   1466 tvhzto(struct timeval *tv)
   1467 {
   1468 	struct timeval t2;
   1469 
   1470 	getmicrotime(&t2);
   1471 	t2.tv_sec = tv->tv_sec - t2.tv_sec;
   1472 	t2.tv_usec = tv->tv_usec - t2.tv_usec;
   1473 	return tvtohz(&t2);
   1474 }
   1475 #endif /* __FreeBSD_version > 300000 */
   1476 
   1477 /*
   1478  * void
   1479  * rmc_delay_action(struct rm_class *cl) - This function is the generic CBQ
   1480  *	delay action routine.  It is invoked via rmc_under_limit when the
   1481  *	packet is discovered to be overlimit.
   1482  *
   1483  *	If the delay action is result of borrow class being overlimit, then
   1484  *	delay for the offtime of the borrowing class that is overlimit.
   1485  *
   1486  *	Returns: NONE
   1487  */
   1488 
   1489 void
   1490 rmc_delay_action(struct rm_class *cl, struct rm_class *borrow)
   1491 {
   1492 	int	t;
   1493 	int64_t	ndelay, extradelay;
   1494 
   1495 	cl->stats_.overactions++;
   1496 	if (borrow != NULL)
   1497 		TS_DELTA(&borrow->undertime_, &cl->overtime_, ndelay);
   1498 	else
   1499 		TS_DELTA(&cl->undertime_, &cl->overtime_, ndelay);
   1500 #ifndef BORROW_OFFTIME
   1501 	ndelay += cl->offtime_;
   1502 #endif
   1503 
   1504 	if (!cl->sleeping_) {
   1505 		CBQTRACE(rmc_delay_action, 'yled', cl->stats_.handle);
   1506 #ifdef BORROW_OFFTIME
   1507 		if (borrow != NULL)
   1508 			extradelay = borrow->offtime_;
   1509 		else
   1510 #endif
   1511 			extradelay = cl->offtime_;
   1512 
   1513 #ifdef ALTQ
   1514 		/*
   1515 		 * XXX recalculate suspend time:
   1516 		 * current undertime is (tidle + pkt_time) calculated
   1517 		 * from the last transmission.
   1518 		 *	tidle: time required to bring avgidle back to 0
   1519 		 *	pkt_time: target waiting time for this class
   1520 		 * we need to replace pkt_time by offtime
   1521 		 */
   1522 		extradelay -= cl->last_pkttime_;
   1523 #endif
   1524 		if (extradelay > 0) {
   1525 			TS_ADD_DELTA(&cl->undertime_, extradelay, &cl->undertime_);
   1526 			ndelay += extradelay;
   1527 		}
   1528 
   1529 		cl->sleeping_ = 1;
   1530 		cl->stats_.delays++;
   1531 
   1532 		/*
   1533 		 * Since packets are phased randomly with respect to the
   1534 		 * clock, 1 tick (the next clock tick) can be an arbitrarily
   1535 		 * short time so we have to wait for at least two ticks.
   1536 		 * NOTE:  If there's no other traffic, we need the timer as
   1537 		 * a 'backstop' to restart this class.
   1538 		 */
   1539 		if (NSEC_TO_USEC(ndelay) > tick * 2) {
   1540 #ifdef __FreeBSD__
   1541 			/* FreeBSD rounds up the tick */
   1542 			t = tvhzto(&cl->undertime_);
   1543 #else
   1544 			/* other BSDs round down the tick */
   1545 			t = tshzto(&cl->undertime_) + 1;
   1546 #endif
   1547 		} else
   1548 			t = 2;
   1549 		CALLOUT_RESET(&cl->callout_, t,
   1550 			      (timeout_t *)rmc_restart, (void *)cl);
   1551 	}
   1552 }
   1553 
   1554 /*
   1555  * void
   1556  * rmc_restart() - is just a helper routine for rmc_delay_action -- it is
   1557  *	called by the system timer code & is responsible checking if the
   1558  *	class is still sleeping (it might have been restarted as a side
   1559  *	effect of the queue scan on a packet arrival) and, if so, restarting
   1560  *	output for the class.  Inspecting the class state & restarting output
   1561  *	require locking the class structure.  In general the driver is
   1562  *	responsible for locking but this is the only routine that is not
   1563  *	called directly or indirectly from the interface driver so it has
   1564  *	know about system locking conventions.  Under bsd, locking is done
   1565  *	by raising IPL to splnet so that's what's implemented here.  On a
   1566  *	different system this would probably need to be changed.
   1567  *
   1568  *	Returns:	NONE
   1569  */
   1570 
   1571 static void
   1572 rmc_restart(struct rm_class *cl)
   1573 {
   1574 	struct rm_ifdat	*ifd = cl->ifdat_;
   1575 	int		 s;
   1576 
   1577 	s = splnet();
   1578 	if (cl->sleeping_) {
   1579 		cl->sleeping_ = 0;
   1580 		cl->undertime_.tv_sec = 0;
   1581 
   1582 		if (ifd->queued_ < ifd->maxqueued_ && ifd->restart != NULL) {
   1583 			CBQTRACE(rmc_restart, 'trts', cl->stats_.handle);
   1584 			(ifd->restart)(ifd->ifq_);
   1585 		}
   1586 	}
   1587 	splx(s);
   1588 }
   1589 
   1590 /*
   1591  * void
   1592  * rmc_root_overlimit(struct rm_class *cl) - This the generic overlimit
   1593  *	handling routine for the root class of the link sharing structure.
   1594  *
   1595  *	Returns: NONE
   1596  */
   1597 
   1598 static void
   1599 rmc_root_overlimit(struct rm_class *cl,
   1600     struct rm_class *borrow)
   1601 {
   1602 	panic("rmc_root_overlimit");
   1603 }
   1604 
   1605 /*
   1606  * Packet Queue handling routines.  Eventually, this is to localize the
   1607  *	effects on the code whether queues are red queues or droptail
   1608  *	queues.
   1609  */
   1610 
   1611 static int
   1612 _rmc_addq(rm_class_t *cl, mbuf_t *m)
   1613 {
   1614 #ifdef ALTQ_RIO
   1615 	if (q_is_rio(cl->q_))
   1616 		return rio_addq((rio_t *)cl->red_, cl->q_, m, cl->pktattr_);
   1617 #endif
   1618 #ifdef ALTQ_RED
   1619 	if (q_is_red(cl->q_))
   1620 		return red_addq(cl->red_, cl->q_, m, cl->pktattr_);
   1621 #endif /* ALTQ_RED */
   1622 
   1623 	if (cl->flags_ & RMCF_CLEARDSCP)
   1624 		write_dsfield(m, cl->pktattr_, 0);
   1625 
   1626 	_addq(cl->q_, m);
   1627 	return 0;
   1628 }
   1629 
   1630 /* note: _rmc_dropq is not called for red */
   1631 static void
   1632 _rmc_dropq(rm_class_t *cl)
   1633 {
   1634 	mbuf_t	*m;
   1635 
   1636 	if ((m = _getq(cl->q_)) != NULL)
   1637 		m_freem(m);
   1638 }
   1639 
   1640 static mbuf_t *
   1641 _rmc_getq(rm_class_t *cl)
   1642 {
   1643 #ifdef ALTQ_RIO
   1644 	if (q_is_rio(cl->q_))
   1645 		return rio_getq((rio_t *)cl->red_, cl->q_);
   1646 #endif
   1647 #ifdef ALTQ_RED
   1648 	if (q_is_red(cl->q_))
   1649 		return red_getq(cl->red_, cl->q_);
   1650 #endif
   1651 	return _getq(cl->q_);
   1652 }
   1653 
   1654 static mbuf_t *
   1655 _rmc_pollq(rm_class_t *cl)
   1656 {
   1657 	return qhead(cl->q_);
   1658 }
   1659 
   1660 #ifdef CBQ_TRACE
   1661 
   1662 struct cbqtrace		 cbqtrace_buffer[NCBQTRACE+1];
   1663 struct cbqtrace		*cbqtrace_ptr = NULL;
   1664 int			 cbqtrace_count;
   1665 
   1666 /*
   1667  * DDB hook to trace cbq events:
   1668  *  the last 1024 events are held in a circular buffer.
   1669  *  use "call cbqtrace_dump(N)" to display 20 events from Nth event.
   1670  */
   1671 void cbqtrace_dump(int);
   1672 static char *rmc_funcname(void *);
   1673 
   1674 static struct rmc_funcs {
   1675 	void	*func;
   1676 	char	*name;
   1677 } rmc_funcs[] =
   1678 {
   1679 	rmc_init,		"rmc_init",
   1680 	rmc_queue_packet,	"rmc_queue_packet",
   1681 	rmc_under_limit,	"rmc_under_limit",
   1682 	rmc_update_class_util,	"rmc_update_class_util",
   1683 	rmc_delay_action,	"rmc_delay_action",
   1684 	rmc_restart,		"rmc_restart",
   1685 	_rmc_wrr_dequeue_next,	"_rmc_wrr_dequeue_next",
   1686 	NULL,			NULL
   1687 };
   1688 
   1689 static char *
   1690 rmc_funcname(void *func)
   1691 {
   1692 	struct rmc_funcs *fp;
   1693 
   1694 	for (fp = rmc_funcs; fp->func != NULL; fp++)
   1695 		if (fp->func == func)
   1696 			return (fp->name);
   1697 	return ("unknown");
   1698 }
   1699 
   1700 void
   1701 cbqtrace_dump(int counter)
   1702 {
   1703 	int	 i, *p;
   1704 	char	*cp;
   1705 
   1706 	counter = counter % NCBQTRACE;
   1707 	p = (int *)&cbqtrace_buffer[counter];
   1708 
   1709 	for (i=0; i<20; i++) {
   1710 		printf("[0x%x] ", *p++);
   1711 		printf("%s: ", rmc_funcname((void *)*p++));
   1712 		cp = (char *)p++;
   1713 		printf("%c%c%c%c: ", cp[0], cp[1], cp[2], cp[3]);
   1714 		printf("%d\n",*p++);
   1715 
   1716 		if (p >= (int *)&cbqtrace_buffer[NCBQTRACE])
   1717 			p = (int *)cbqtrace_buffer;
   1718 	}
   1719 }
   1720 #endif /* CBQ_TRACE */
   1721 #endif /* ALTQ_CBQ */
   1722 
   1723 #if defined(ALTQ_CBQ) || defined(ALTQ_RED) || defined(ALTQ_RIO) || defined(ALTQ_HFSC) || defined(ALTQ_PRIQ)
   1724 #if !defined(__GNUC__) || defined(ALTQ_DEBUG)
   1725 
   1726 void
   1727 _addq(class_queue_t *q, mbuf_t *m)
   1728 {
   1729         mbuf_t	*m0;
   1730 
   1731 	if ((m0 = qtail(q)) != NULL)
   1732 		m->m_nextpkt = m0->m_nextpkt;
   1733 	else
   1734 		m0 = m;
   1735 	m0->m_nextpkt = m;
   1736 	qtail(q) = m;
   1737 	qlen(q)++;
   1738 }
   1739 
   1740 mbuf_t *
   1741 _getq(class_queue_t *q)
   1742 {
   1743 	mbuf_t	*m, *m0;
   1744 
   1745 	if ((m = qtail(q)) == NULL)
   1746 		return NULL;
   1747 	if ((m0 = m->m_nextpkt) != m)
   1748 		m->m_nextpkt = m0->m_nextpkt;
   1749 	else {
   1750 		ASSERT(qlen(q) == 1);
   1751 		qtail(q) = NULL;
   1752 	}
   1753 	qlen(q)--;
   1754 	m0->m_nextpkt = NULL;
   1755 	return m0;
   1756 }
   1757 
   1758 /* drop a packet at the tail of the queue */
   1759 mbuf_t *
   1760 _getq_tail(class_queue_t *q)
   1761 {
   1762 	mbuf_t	*m, *m0, *prev;
   1763 
   1764 	if ((m = m0 = qtail(q)) == NULL)
   1765 		return NULL;
   1766 	do {
   1767 		prev = m0;
   1768 		m0 = m0->m_nextpkt;
   1769 	} while (m0 != m);
   1770 	prev->m_nextpkt = m->m_nextpkt;
   1771 	if (prev == m)  {
   1772 		ASSERT(qlen(q) == 1);
   1773 		qtail(q) = NULL;
   1774 	} else
   1775 		qtail(q) = prev;
   1776 	qlen(q)--;
   1777 	m->m_nextpkt = NULL;
   1778 	return m;
   1779 }
   1780 
   1781 /* randomly select a packet in the queue */
   1782 mbuf_t *
   1783 _getq_random(class_queue_t *q)
   1784 {
   1785 	struct mbuf	*m;
   1786 	int		 i, n;
   1787 
   1788 	if ((m = qtail(q)) == NULL)
   1789 		return NULL;
   1790 	if (m->m_nextpkt == m) {
   1791 		ASSERT(qlen(q) == 1);
   1792 		qtail(q) = NULL;
   1793 	} else {
   1794 		struct mbuf *prev = NULL;
   1795 
   1796 		n = cprng_fast32() % qlen(q) + 1;
   1797 		for (i = 0; i < n; i++) {
   1798 			prev = m;
   1799 			m = m->m_nextpkt;
   1800 		}
   1801 		prev->m_nextpkt = m->m_nextpkt;
   1802 		if (m == qtail(q))
   1803 			qtail(q) = prev;
   1804 	}
   1805 	qlen(q)--;
   1806 	m->m_nextpkt = NULL;
   1807 	return m;
   1808 }
   1809 
   1810 void
   1811 _removeq(class_queue_t *q, mbuf_t *m)
   1812 {
   1813 	mbuf_t	*m0, *prev;
   1814 
   1815 	m0 = qtail(q);
   1816 	do {
   1817 		prev = m0;
   1818 		m0 = m0->m_nextpkt;
   1819 	} while (m0 != m);
   1820 	prev->m_nextpkt = m->m_nextpkt;
   1821 	if (prev == m)
   1822 		qtail(q) = NULL;
   1823 	else if (qtail(q) == m)
   1824 		qtail(q) = prev;
   1825 	qlen(q)--;
   1826 }
   1827 
   1828 void
   1829 _flushq(class_queue_t *q)
   1830 {
   1831 	mbuf_t *m;
   1832 
   1833 	while ((m = _getq(q)) != NULL)
   1834 		m_freem(m);
   1835 	ASSERT(qlen(q) == 0);
   1836 }
   1837 
   1838 #endif /* !__GNUC__ || ALTQ_DEBUG */
   1839 #endif /* ALTQ_CBQ || ALTQ_RED || ALTQ_RIO || ALTQ_HFSC || ALTQ_PRIQ */
   1840