Return to gen_estimator.c CVS log

Up to [Development] / linux-2.6-xfs / net / core

Update 2.6.x-xfs to 2.6.23-rc4.

Also update fs/xfs with external mainline changes.
There were 12 such missing commits that I detected:

--------
commit ad690ef9e690f6c31f7d310b09ef1314bcec9033
Author: Al Viro <viro@ftp.linux.org.uk>
    xfs ioctl __user annotations

commit 20c2df83d25c6a95affe6157a4c9cac4cf5ffaac
Author: Paul Mundt <lethal@linux-sh.org>
    mm: Remove slab destructors from kmem_cache_create().

commit d0217ac04ca6591841e5665f518e38064f4e65bd
Author: Nick Piggin <npiggin@suse.de>
    mm: fault feedback #1

commit 54cb8821de07f2ffcd28c380ce9b93d5784b40d7
Author: Nick Piggin <npiggin@suse.de>
    mm: merge populate and nopage into fault (fixes nonlinear)

commit d00806b183152af6d24f46f0c33f14162ca1262a
Author: Nick Piggin <npiggin@suse.de>
    mm: fix fault vs invalidate race for linear mappings

commit a569425512253992cc64ebf8b6d00a62f986db3e
Author: Christoph Hellwig <hch@infradead.org>
    knfsd: exportfs: add exportfs.h header

commit 831441862956fffa17b9801db37e6ea1650b0f69
Author: Rafael J. Wysocki <rjw@sisk.pl>
    Freezer: make kernel threads nonfreezable by default

commit 8e1f936b73150f5095448a0fee6d4f30a1f9001d
Author: Rusty Russell <rusty@rustcorp.com.au>
    mm: clean up and kernelify shrinker registration

commit 5ffc4ef45b3b0a57872f631b4e4ceb8ace0d7496
Author: Jens Axboe <jens.axboe@oracle.com>
    sendfile: remove .sendfile from filesystems that use generic_file_sendfile()

commit 8bb7844286fb8c9fce6f65d8288aeb09d03a5e0d
Author: Rafael J. Wysocki <rjw@sisk.pl>
    Add suspend-related notifications for CPU hotplug

commit 59c51591a0ac7568824f541f57de967e88adaa07
Author: Michael Opdenacker <michael@free-electrons.com>
    Fix occurrences of "the the "

commit 0ceb331433e8aad9c5f441a965d7c681f8b9046f
Author: Dmitriy Monakhov <dmonakhov@openvz.org>
    mm: move common segment checks to separate helper function
--------
Merge of 2.6.x-xfs-melb:linux:29656b by kenmcd.

/*
 * net/sched/gen_estimator.c	Simple rate estimator.
 *
 *		This program is free software; you can redistribute it and/or
 *		modify it under the terms of the GNU General Public License
 *		as published by the Free Software Foundation; either version
 *		2 of the License, or (at your option) any later version.
 *
 * Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
 *
 * Changes:
 *              Jamal Hadi Salim - moved it to net/core and reshulfed
 *              names to make it usable in general net subsystem.
 */

#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/bitops.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/jiffies.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/in.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/rtnetlink.h>
#include <linux/init.h>
#include <net/sock.h>
#include <net/gen_stats.h>

/*
   This code is NOT intended to be used for statistics collection,
   its purpose is to provide a base for statistical multiplexing
   for controlled load service.
   If you need only statistics, run a user level daemon which
   periodically reads byte counters.

   Unfortunately, rate estimation is not a very easy task.
   F.e. I did not find a simple way to estimate the current peak rate
   and even failed to formulate the problem 8)8)

   So I preferred not to built an estimator into the scheduler,
   but run this task separately.
   Ideally, it should be kernel thread(s), but for now it runs
   from timers, which puts apparent top bounds on the number of rated
   flows, has minimal overhead on small, but is enough
   to handle controlled load service, sets of aggregates.

   We measure rate over A=(1<<interval) seconds and evaluate EWMA:

   avrate = avrate*(1-W) + rate*W

   where W is chosen as negative power of 2: W = 2^(-ewma_log)

   The resulting time constant is:

   T = A/(-ln(1-W))


   NOTES.

   * The stored value for avbps is scaled by 2^5, so that maximal
     rate is ~1Gbit, avpps is scaled by 2^10.

   * Minimal interval is HZ/4=250msec (it is the greatest common divisor
     for HZ=100 and HZ=1024 8)), maximal interval
     is (HZ*2^EST_MAX_INTERVAL)/4 = 8sec. Shorter intervals
     are too expensive, longer ones can be implemented
     at user level painlessly.
 */

#define EST_MAX_INTERVAL	5

struct gen_estimator
{
	struct list_head	list;
	struct gnet_stats_basic	*bstats;
	struct gnet_stats_rate_est	*rate_est;
	spinlock_t		*stats_lock;
	int			ewma_log;
	u64			last_bytes;
	u32			last_packets;
	u32			avpps;
	u32			avbps;
	struct rcu_head		e_rcu;
};

struct gen_estimator_head
{
	struct timer_list	timer;
	struct list_head	list;
};

static struct gen_estimator_head elist[EST_MAX_INTERVAL+1];

/* Protects against NULL dereference */
static DEFINE_RWLOCK(est_lock);

static void est_timer(unsigned long arg)
{
	int idx = (int)arg;
	struct gen_estimator *e;

	rcu_read_lock();
	list_for_each_entry_rcu(e, &elist[idx].list, list) {
		u64 nbytes;
		u32 npackets;
		u32 rate;

		spin_lock(e->stats_lock);
		read_lock(&est_lock);
		if (e->bstats == NULL)
			goto skip;

		nbytes = e->bstats->bytes;
		npackets = e->bstats->packets;
		rate = (nbytes - e->last_bytes)<<(7 - idx);
		e->last_bytes = nbytes;
		e->avbps += ((long)rate - (long)e->avbps) >> e->ewma_log;
		e->rate_est->bps = (e->avbps+0xF)>>5;

		rate = (npackets - e->last_packets)<<(12 - idx);
		e->last_packets = npackets;
		e->avpps += ((long)rate - (long)e->avpps) >> e->ewma_log;
		e->rate_est->pps = (e->avpps+0x1FF)>>10;
skip:
		read_unlock(&est_lock);
		spin_unlock(e->stats_lock);
	}

	if (!list_empty(&elist[idx].list))
		mod_timer(&elist[idx].timer, jiffies + ((HZ<<idx)/4));
	rcu_read_unlock();
}

/**
 * gen_new_estimator - create a new rate estimator
 * @bstats: basic statistics
 * @rate_est: rate estimator statistics
 * @stats_lock: statistics lock
 * @opt: rate estimator configuration TLV
 *
 * Creates a new rate estimator with &bstats as source and &rate_est
 * as destination. A new timer with the interval specified in the
 * configuration TLV is created. Upon each interval, the latest statistics
 * will be read from &bstats and the estimated rate will be stored in
 * &rate_est with the statistics lock grabed during this period.
 *
 * Returns 0 on success or a negative error code.
 *
 * NOTE: Called under rtnl_mutex
 */
int gen_new_estimator(struct gnet_stats_basic *bstats,
		      struct gnet_stats_rate_est *rate_est,
		      spinlock_t *stats_lock,
		      struct rtattr *opt)
{
	struct gen_estimator *est;
	struct gnet_estimator *parm = RTA_DATA(opt);
	int idx;

	if (RTA_PAYLOAD(opt) < sizeof(*parm))
		return -EINVAL;

	if (parm->interval < -2 || parm->interval > 3)
		return -EINVAL;

	est = kzalloc(sizeof(*est), GFP_KERNEL);
	if (est == NULL)
		return -ENOBUFS;

	idx = parm->interval + 2;
	est->bstats = bstats;
	est->rate_est = rate_est;
	est->stats_lock = stats_lock;
	est->ewma_log = parm->ewma_log;
	est->last_bytes = bstats->bytes;
	est->avbps = rate_est->bps<<5;
	est->last_packets = bstats->packets;
	est->avpps = rate_est->pps<<10;

	if (!elist[idx].timer.function) {
		INIT_LIST_HEAD(&elist[idx].list);
		setup_timer(&elist[idx].timer, est_timer, idx);
	}

	if (list_empty(&elist[idx].list))
		mod_timer(&elist[idx].timer, jiffies + ((HZ<<idx)/4));

	list_add_rcu(&est->list, &elist[idx].list);
	return 0;
}

static void __gen_kill_estimator(struct rcu_head *head)
{
	struct gen_estimator *e = container_of(head,
					struct gen_estimator, e_rcu);
	kfree(e);
}

/**
 * gen_kill_estimator - remove a rate estimator
 * @bstats: basic statistics
 * @rate_est: rate estimator statistics
 *
 * Removes the rate estimator specified by &bstats and &rate_est
 * and deletes the timer.
 *
 * NOTE: Called under rtnl_mutex
 */
void gen_kill_estimator(struct gnet_stats_basic *bstats,
	struct gnet_stats_rate_est *rate_est)
{
	int idx;
	struct gen_estimator *e, *n;

	for (idx=0; idx <= EST_MAX_INTERVAL; idx++) {

		/* Skip non initialized indexes */
		if (!elist[idx].timer.function)
			continue;

		list_for_each_entry_safe(e, n, &elist[idx].list, list) {
			if (e->rate_est != rate_est || e->bstats != bstats)
				continue;

			write_lock_bh(&est_lock);
			e->bstats = NULL;
			write_unlock_bh(&est_lock);

			list_del_rcu(&e->list);
			call_rcu(&e->e_rcu, __gen_kill_estimator);
		}
	}
}

/**
 * gen_replace_estimator - replace rate estimator configruation
 * @bstats: basic statistics
 * @rate_est: rate estimator statistics
 * @stats_lock: statistics lock
 * @opt: rate estimator configuration TLV
 *
 * Replaces the configuration of a rate estimator by calling
 * gen_kill_estimator() and gen_new_estimator().
 *
 * Returns 0 on success or a negative error code.
 */
int
gen_replace_estimator(struct gnet_stats_basic *bstats,
	struct gnet_stats_rate_est *rate_est, spinlock_t *stats_lock,
	struct rtattr *opt)
{
    gen_kill_estimator(bstats, rate_est);
    return gen_new_estimator(bstats, rate_est, stats_lock, opt);
}


EXPORT_SYMBOL(gen_kill_estimator);
EXPORT_SYMBOL(gen_new_estimator);
EXPORT_SYMBOL(gen_replace_estimator);