linux/net/core/gen_stats.c
John Fastabend 22e0f8b932 net: sched: make bstats per cpu and estimator RCU safe
In order to run qdisc's without locking statistics and estimators
need to be handled correctly.

To resolve bstats make the statistics per cpu. And because this is
only needed for qdiscs that are running without locks which is not
the case for most qdiscs in the near future only create percpu
stats when qdiscs set the TCQ_F_CPUSTATS flag.

Next because estimators use the bstats to calculate packets per
second and bytes per second the estimator code paths are updated
to use the per cpu statistics.

Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-30 01:02:26 -04:00

307 lines
8.1 KiB
C

/*
* net/core/gen_stats.c
*
* 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: Thomas Graf <tgraf@suug.ch>
* Jamal Hadi Salim
* Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
*
* See Documentation/networking/gen_stats.txt
*/
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/socket.h>
#include <linux/rtnetlink.h>
#include <linux/gen_stats.h>
#include <net/netlink.h>
#include <net/gen_stats.h>
static inline int
gnet_stats_copy(struct gnet_dump *d, int type, void *buf, int size)
{
if (nla_put(d->skb, type, size, buf))
goto nla_put_failure;
return 0;
nla_put_failure:
spin_unlock_bh(d->lock);
return -1;
}
/**
* gnet_stats_start_copy_compat - start dumping procedure in compatibility mode
* @skb: socket buffer to put statistics TLVs into
* @type: TLV type for top level statistic TLV
* @tc_stats_type: TLV type for backward compatibility struct tc_stats TLV
* @xstats_type: TLV type for backward compatibility xstats TLV
* @lock: statistics lock
* @d: dumping handle
*
* Initializes the dumping handle, grabs the statistic lock and appends
* an empty TLV header to the socket buffer for use a container for all
* other statistic TLVS.
*
* The dumping handle is marked to be in backward compatibility mode telling
* all gnet_stats_copy_XXX() functions to fill a local copy of struct tc_stats.
*
* Returns 0 on success or -1 if the room in the socket buffer was not sufficient.
*/
int
gnet_stats_start_copy_compat(struct sk_buff *skb, int type, int tc_stats_type,
int xstats_type, spinlock_t *lock, struct gnet_dump *d)
__acquires(lock)
{
memset(d, 0, sizeof(*d));
spin_lock_bh(lock);
d->lock = lock;
if (type)
d->tail = (struct nlattr *)skb_tail_pointer(skb);
d->skb = skb;
d->compat_tc_stats = tc_stats_type;
d->compat_xstats = xstats_type;
if (d->tail)
return gnet_stats_copy(d, type, NULL, 0);
return 0;
}
EXPORT_SYMBOL(gnet_stats_start_copy_compat);
/**
* gnet_stats_start_copy_compat - start dumping procedure in compatibility mode
* @skb: socket buffer to put statistics TLVs into
* @type: TLV type for top level statistic TLV
* @lock: statistics lock
* @d: dumping handle
*
* Initializes the dumping handle, grabs the statistic lock and appends
* an empty TLV header to the socket buffer for use a container for all
* other statistic TLVS.
*
* Returns 0 on success or -1 if the room in the socket buffer was not sufficient.
*/
int
gnet_stats_start_copy(struct sk_buff *skb, int type, spinlock_t *lock,
struct gnet_dump *d)
{
return gnet_stats_start_copy_compat(skb, type, 0, 0, lock, d);
}
EXPORT_SYMBOL(gnet_stats_start_copy);
static void
__gnet_stats_copy_basic_cpu(struct gnet_stats_basic_packed *bstats,
struct gnet_stats_basic_cpu __percpu *cpu)
{
int i;
for_each_possible_cpu(i) {
struct gnet_stats_basic_cpu *bcpu = per_cpu_ptr(cpu, i);
unsigned int start;
__u64 bytes;
__u32 packets;
do {
start = u64_stats_fetch_begin_irq(&bcpu->syncp);
bytes = bcpu->bstats.bytes;
packets = bcpu->bstats.packets;
} while (u64_stats_fetch_retry_irq(&bcpu->syncp, start));
bstats->bytes += bcpu->bstats.bytes;
bstats->packets += bcpu->bstats.packets;
}
}
void
__gnet_stats_copy_basic(struct gnet_stats_basic_packed *bstats,
struct gnet_stats_basic_cpu __percpu *cpu,
struct gnet_stats_basic_packed *b)
{
if (cpu) {
__gnet_stats_copy_basic_cpu(bstats, cpu);
} else {
bstats->bytes = b->bytes;
bstats->packets = b->packets;
}
}
EXPORT_SYMBOL(__gnet_stats_copy_basic);
/**
* gnet_stats_copy_basic - copy basic statistics into statistic TLV
* @d: dumping handle
* @b: basic statistics
*
* Appends the basic statistics to the top level TLV created by
* gnet_stats_start_copy().
*
* Returns 0 on success or -1 with the statistic lock released
* if the room in the socket buffer was not sufficient.
*/
int
gnet_stats_copy_basic(struct gnet_dump *d,
struct gnet_stats_basic_cpu __percpu *cpu,
struct gnet_stats_basic_packed *b)
{
struct gnet_stats_basic_packed bstats = {0};
__gnet_stats_copy_basic(&bstats, cpu, b);
if (d->compat_tc_stats) {
d->tc_stats.bytes = bstats.bytes;
d->tc_stats.packets = bstats.packets;
}
if (d->tail) {
struct gnet_stats_basic sb;
memset(&sb, 0, sizeof(sb));
sb.bytes = bstats.bytes;
sb.packets = bstats.packets;
return gnet_stats_copy(d, TCA_STATS_BASIC, &sb, sizeof(sb));
}
return 0;
}
EXPORT_SYMBOL(gnet_stats_copy_basic);
/**
* gnet_stats_copy_rate_est - copy rate estimator statistics into statistics TLV
* @d: dumping handle
* @b: basic statistics
* @r: rate estimator statistics
*
* Appends the rate estimator statistics to the top level TLV created by
* gnet_stats_start_copy().
*
* Returns 0 on success or -1 with the statistic lock released
* if the room in the socket buffer was not sufficient.
*/
int
gnet_stats_copy_rate_est(struct gnet_dump *d,
const struct gnet_stats_basic_packed *b,
struct gnet_stats_rate_est64 *r)
{
struct gnet_stats_rate_est est;
int res;
if (b && !gen_estimator_active(b, r))
return 0;
est.bps = min_t(u64, UINT_MAX, r->bps);
/* we have some time before reaching 2^32 packets per second */
est.pps = r->pps;
if (d->compat_tc_stats) {
d->tc_stats.bps = est.bps;
d->tc_stats.pps = est.pps;
}
if (d->tail) {
res = gnet_stats_copy(d, TCA_STATS_RATE_EST, &est, sizeof(est));
if (res < 0 || est.bps == r->bps)
return res;
/* emit 64bit stats only if needed */
return gnet_stats_copy(d, TCA_STATS_RATE_EST64, r, sizeof(*r));
}
return 0;
}
EXPORT_SYMBOL(gnet_stats_copy_rate_est);
/**
* gnet_stats_copy_queue - copy queue statistics into statistics TLV
* @d: dumping handle
* @q: queue statistics
*
* Appends the queue statistics to the top level TLV created by
* gnet_stats_start_copy().
*
* Returns 0 on success or -1 with the statistic lock released
* if the room in the socket buffer was not sufficient.
*/
int
gnet_stats_copy_queue(struct gnet_dump *d, struct gnet_stats_queue *q)
{
if (d->compat_tc_stats) {
d->tc_stats.drops = q->drops;
d->tc_stats.qlen = q->qlen;
d->tc_stats.backlog = q->backlog;
d->tc_stats.overlimits = q->overlimits;
}
if (d->tail)
return gnet_stats_copy(d, TCA_STATS_QUEUE, q, sizeof(*q));
return 0;
}
EXPORT_SYMBOL(gnet_stats_copy_queue);
/**
* gnet_stats_copy_app - copy application specific statistics into statistics TLV
* @d: dumping handle
* @st: application specific statistics data
* @len: length of data
*
* Appends the application specific statistics to the top level TLV created by
* gnet_stats_start_copy() and remembers the data for XSTATS if the dumping
* handle is in backward compatibility mode.
*
* Returns 0 on success or -1 with the statistic lock released
* if the room in the socket buffer was not sufficient.
*/
int
gnet_stats_copy_app(struct gnet_dump *d, void *st, int len)
{
if (d->compat_xstats) {
d->xstats = st;
d->xstats_len = len;
}
if (d->tail)
return gnet_stats_copy(d, TCA_STATS_APP, st, len);
return 0;
}
EXPORT_SYMBOL(gnet_stats_copy_app);
/**
* gnet_stats_finish_copy - finish dumping procedure
* @d: dumping handle
*
* Corrects the length of the top level TLV to include all TLVs added
* by gnet_stats_copy_XXX() calls. Adds the backward compatibility TLVs
* if gnet_stats_start_copy_compat() was used and releases the statistics
* lock.
*
* Returns 0 on success or -1 with the statistic lock released
* if the room in the socket buffer was not sufficient.
*/
int
gnet_stats_finish_copy(struct gnet_dump *d)
{
if (d->tail)
d->tail->nla_len = skb_tail_pointer(d->skb) - (u8 *)d->tail;
if (d->compat_tc_stats)
if (gnet_stats_copy(d, d->compat_tc_stats, &d->tc_stats,
sizeof(d->tc_stats)) < 0)
return -1;
if (d->compat_xstats && d->xstats) {
if (gnet_stats_copy(d, d->compat_xstats, d->xstats,
d->xstats_len) < 0)
return -1;
}
spin_unlock_bh(d->lock);
return 0;
}
EXPORT_SYMBOL(gnet_stats_finish_copy);