zfs-builds-mm/zfs-0.8.4/cmd/zed/agents/fmd_serd.c

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2020-07-19 16:21:53 +02:00
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (the "License"). You may not use this file except in compliance
* with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2004 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*
* Copyright (c) 2016, Intel Corporation.
*/
#include <assert.h>
#include <stddef.h>
#include <stdlib.h>
#include <strings.h>
#include <sys/list.h>
#include <sys/time.h>
#include "fmd_api.h"
#include "fmd_serd.h"
#include "../zed_log.h"
#define FMD_STR_BUCKETS 211
#ifdef SERD_ENG_DEBUG
#define serd_log_msg(fmt, ...) \
zed_log_msg(LOG_INFO, fmt, __VA_ARGS__)
#else
#define serd_log_msg(fmt, ...)
#endif
/*
* SERD Engine Backend
*/
/*
* Compute the delta between events in nanoseconds. To account for very old
* events which are replayed, we must handle the case where time is negative.
* We convert the hrtime_t's to unsigned 64-bit integers and then handle the
* case where 'old' is greater than 'new' (i.e. high-res time has wrapped).
*/
static hrtime_t
fmd_event_delta(hrtime_t t1, hrtime_t t2)
{
uint64_t old = t1;
uint64_t new = t2;
return (new >= old ? new - old : (UINT64_MAX - old) + new + 1);
}
static fmd_serd_eng_t *
fmd_serd_eng_alloc(const char *name, uint64_t n, hrtime_t t)
{
fmd_serd_eng_t *sgp;
sgp = malloc(sizeof (fmd_serd_eng_t));
bzero(sgp, sizeof (fmd_serd_eng_t));
sgp->sg_name = strdup(name);
sgp->sg_flags = FMD_SERD_DIRTY;
sgp->sg_n = n;
sgp->sg_t = t;
list_create(&sgp->sg_list, sizeof (fmd_serd_elem_t),
offsetof(fmd_serd_elem_t, se_list));
return (sgp);
}
static void
fmd_serd_eng_free(fmd_serd_eng_t *sgp)
{
fmd_serd_eng_reset(sgp);
free(sgp->sg_name);
list_destroy(&sgp->sg_list);
free(sgp);
}
/*
* sourced from fmd_string.c
*/
static ulong_t
fmd_strhash(const char *key)
{
ulong_t g, h = 0;
const char *p;
for (p = key; *p != '\0'; p++) {
h = (h << 4) + *p;
if ((g = (h & 0xf0000000)) != 0) {
h ^= (g >> 24);
h ^= g;
}
}
return (h);
}
void
fmd_serd_hash_create(fmd_serd_hash_t *shp)
{
shp->sh_hashlen = FMD_STR_BUCKETS;
shp->sh_hash = calloc(shp->sh_hashlen, sizeof (void *));
shp->sh_count = 0;
}
void
fmd_serd_hash_destroy(fmd_serd_hash_t *shp)
{
fmd_serd_eng_t *sgp, *ngp;
uint_t i;
for (i = 0; i < shp->sh_hashlen; i++) {
for (sgp = shp->sh_hash[i]; sgp != NULL; sgp = ngp) {
ngp = sgp->sg_next;
fmd_serd_eng_free(sgp);
}
}
free(shp->sh_hash);
bzero(shp, sizeof (fmd_serd_hash_t));
}
void
fmd_serd_hash_apply(fmd_serd_hash_t *shp, fmd_serd_eng_f *func, void *arg)
{
fmd_serd_eng_t *sgp;
uint_t i;
for (i = 0; i < shp->sh_hashlen; i++) {
for (sgp = shp->sh_hash[i]; sgp != NULL; sgp = sgp->sg_next)
func(sgp, arg);
}
}
fmd_serd_eng_t *
fmd_serd_eng_insert(fmd_serd_hash_t *shp, const char *name,
uint_t n, hrtime_t t)
{
uint_t h = fmd_strhash(name) % shp->sh_hashlen;
fmd_serd_eng_t *sgp = fmd_serd_eng_alloc(name, n, t);
serd_log_msg(" SERD Engine: inserting %s N %d T %llu",
name, (int)n, (long long unsigned)t);
sgp->sg_next = shp->sh_hash[h];
shp->sh_hash[h] = sgp;
shp->sh_count++;
return (sgp);
}
fmd_serd_eng_t *
fmd_serd_eng_lookup(fmd_serd_hash_t *shp, const char *name)
{
uint_t h = fmd_strhash(name) % shp->sh_hashlen;
fmd_serd_eng_t *sgp;
for (sgp = shp->sh_hash[h]; sgp != NULL; sgp = sgp->sg_next) {
if (strcmp(name, sgp->sg_name) == 0)
return (sgp);
}
return (NULL);
}
void
fmd_serd_eng_delete(fmd_serd_hash_t *shp, const char *name)
{
uint_t h = fmd_strhash(name) % shp->sh_hashlen;
fmd_serd_eng_t *sgp, **pp = &shp->sh_hash[h];
serd_log_msg(" SERD Engine: deleting %s", name);
for (sgp = *pp; sgp != NULL; sgp = sgp->sg_next) {
if (strcmp(sgp->sg_name, name) != 0)
pp = &sgp->sg_next;
else
break;
}
if (sgp != NULL) {
*pp = sgp->sg_next;
fmd_serd_eng_free(sgp);
assert(shp->sh_count != 0);
shp->sh_count--;
}
}
static void
fmd_serd_eng_discard(fmd_serd_eng_t *sgp, fmd_serd_elem_t *sep)
{
list_remove(&sgp->sg_list, sep);
sgp->sg_count--;
serd_log_msg(" SERD Engine: discarding %s, %d remaining",
sgp->sg_name, (int)sgp->sg_count);
free(sep);
}
int
fmd_serd_eng_record(fmd_serd_eng_t *sgp, hrtime_t hrt)
{
fmd_serd_elem_t *sep, *oep;
/*
* If the fired flag is already set, return false and discard the
* event. This means that the caller will only see the engine "fire"
* once until fmd_serd_eng_reset() is called. The fmd_serd_eng_fired()
* function can also be used in combination with fmd_serd_eng_record().
*/
if (sgp->sg_flags & FMD_SERD_FIRED) {
serd_log_msg(" SERD Engine: record %s already fired!",
sgp->sg_name);
return (FMD_B_FALSE);
}
while (sgp->sg_count >= sgp->sg_n)
fmd_serd_eng_discard(sgp, list_tail(&sgp->sg_list));
sep = malloc(sizeof (fmd_serd_elem_t));
sep->se_hrt = hrt;
list_insert_head(&sgp->sg_list, sep);
sgp->sg_count++;
serd_log_msg(" SERD Engine: recording %s of %d (%llu)",
sgp->sg_name, (int)sgp->sg_count, (long long unsigned)hrt);
/*
* Pick up the oldest element pointer for comparison to 'sep'. We must
* do this after adding 'sep' because 'oep' and 'sep' can be the same.
*/
oep = list_tail(&sgp->sg_list);
if (sgp->sg_count >= sgp->sg_n &&
fmd_event_delta(oep->se_hrt, sep->se_hrt) <= sgp->sg_t) {
sgp->sg_flags |= FMD_SERD_FIRED | FMD_SERD_DIRTY;
serd_log_msg(" SERD Engine: fired %s", sgp->sg_name);
return (FMD_B_TRUE);
}
sgp->sg_flags |= FMD_SERD_DIRTY;
return (FMD_B_FALSE);
}
int
fmd_serd_eng_fired(fmd_serd_eng_t *sgp)
{
return (sgp->sg_flags & FMD_SERD_FIRED);
}
int
fmd_serd_eng_empty(fmd_serd_eng_t *sgp)
{
return (sgp->sg_count == 0);
}
void
fmd_serd_eng_reset(fmd_serd_eng_t *sgp)
{
serd_log_msg(" SERD Engine: resetting %s", sgp->sg_name);
while (sgp->sg_count != 0)
fmd_serd_eng_discard(sgp, list_head(&sgp->sg_list));
sgp->sg_flags &= ~FMD_SERD_FIRED;
sgp->sg_flags |= FMD_SERD_DIRTY;
}
void
fmd_serd_eng_gc(fmd_serd_eng_t *sgp)
{
fmd_serd_elem_t *sep, *nep;
hrtime_t hrt;
if (sgp->sg_count == 0 || (sgp->sg_flags & FMD_SERD_FIRED))
return; /* no garbage collection needed if empty or fired */
sep = list_head(&sgp->sg_list);
if (sep == NULL)
return;
hrt = sep->se_hrt - sgp->sg_t;
for (sep = list_head(&sgp->sg_list); sep != NULL; sep = nep) {
if (sep->se_hrt >= hrt)
break; /* sep and subsequent events are all within T */
nep = list_next(&sgp->sg_list, sep);
fmd_serd_eng_discard(sgp, sep);
sgp->sg_flags |= FMD_SERD_DIRTY;
}
}