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lib/dns/adb.c: Use atomics for adb quota values and reference counting

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This commit is contained in:
Witold Kręcicki
2019-01-22 10:47:18 +01:00
committed by Ondřej Surý
parent b9f4ba19a6
commit bad5a523c2
1 changed files with 35 additions and 42 deletions
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77
lib/dns/adb.c
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@@ -252,8 +252,8 @@ struct dns_adbentry {
unsigned char to4096; /* Our max. */
uint8_t mode;
uint32_t quota;
uint32_t active;
atomic_uint_fast32_t quota;
atomic_uint_fast32_t active;
double atr;
/*
@@ -1832,9 +1832,9 @@ new_adbentry(dns_adb_t *adb) {
e->srtt = (isc_random_uniform(0x1f)) + 1;
e->lastage = 0;
e->expires = 0;
e->active = 0;
atomic_init(&e->active, 0);
e->mode = 0;
e->quota = adb->quota;
atomic_init(&e->quota, adb->quota);
e->atr = 0.0;
ISC_LIST_INIT(e->lameinfo);
ISC_LINK_INIT(e, plink);
@@ -2161,8 +2161,10 @@ log_quota(dns_adbentry_t *entry, const char *fmt, ...) {
isc_netaddr_format(&netaddr, addrbuf, sizeof(addrbuf));
isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE, DNS_LOGMODULE_ADB,
ISC_LOG_INFO, "adb: quota %s (%u/%u): %s",
addrbuf, entry->active, entry->quota, msgbuf);
ISC_LOG_INFO,
"adb: quota %s (%" PRIuFAST32 "/%" PRIuFAST32 "): %s",
addrbuf, atomic_load_relaxed(&entry->active),
atomic_load_relaxed(&entry->quota), msgbuf);
}
static void
@@ -2185,9 +2187,7 @@ copy_namehook_lists(dns_adb_t *adb, dns_adbfind_t *find,
INSIST(bucket != DNS_ADB_INVALIDBUCKET);
LOCK(&adb->entrylocks[bucket]);
if (entry->quota != 0 &&
entry->active >= entry->quota)
{
if (dns_adbentry_overquota(entry)) {
find->options |=
(DNS_ADBFIND_LAMEPRUNED|
DNS_ADBFIND_OVERQUOTA);
@@ -2225,9 +2225,7 @@ copy_namehook_lists(dns_adb_t *adb, dns_adbfind_t *find,
INSIST(bucket != DNS_ADB_INVALIDBUCKET);
LOCK(&adb->entrylocks[bucket]);
if (entry->quota != 0 &&
entry->active >= entry->quota)
{
if (dns_adbentry_overquota(entry)) {
find->options |=
(DNS_ADBFIND_LAMEPRUNED|
DNS_ADBFIND_OVERQUOTA);
@@ -3534,8 +3532,8 @@ dump_entry(FILE *f, dns_adb_t *adb, dns_adbentry_t *entry,
fprintf(f, " [ttl %d]", (int)(entry->expires - now));
if (adb != NULL && adb->quota != 0 && adb->atr_freq != 0) {
fprintf(f, " [atr %0.2f] [quota %u]",
entry->atr, entry->quota);
fprintf(f, " [atr %0.2f] [quota %" PRIuFAST32 "]",
entry->atr, atomic_load_relaxed(&entry->quota));
}
fprintf(f, "\n");
@@ -4257,21 +4255,25 @@ maybe_adjust_quota(dns_adb_t *adb, dns_adbaddrinfo_t *addr,
addr->entry->atr = ISC_CLAMP(addr->entry->atr, 0.0, 1.0);
if (addr->entry->atr < adb->atr_low && addr->entry->mode > 0) {
addr->entry->quota = adb->quota *
quota_adj[--addr->entry->mode] / 10000;
log_quota(addr->entry, "atr %0.2f, quota increased to %u",
addr->entry->atr, addr->entry->quota);
uint_fast32_t new_quota =
adb->quota * quota_adj[--addr->entry->mode] / 10000;
atomic_store_release(&addr->entry->quota,
ISC_MIN(1, new_quota));
log_quota(addr->entry, "atr %0.2f, quota increased to %"
PRIuFAST32,
addr->entry->atr,
new_quota);
} else if (addr->entry->atr > adb->atr_high &&
addr->entry->mode < (QUOTA_ADJ_SIZE - 1)) {
addr->entry->quota = adb->quota *
quota_adj[++addr->entry->mode] / 10000;
log_quota(addr->entry, "atr %0.2f, quota decreased to %u",
addr->entry->atr, addr->entry->quota);
uint_fast32_t new_quota =
adb->quota * quota_adj[++addr->entry->mode] / 10000;
atomic_store_release(&addr->entry->quota,
ISC_MIN(1, new_quota));
log_quota(addr->entry, "atr %0.2f, quota decreased to %"
PRIuFAST32,
addr->entry->atr,
new_quota);
}
/* Ensure we don't drop to zero */
if (addr->entry->quota == 0)
addr->entry->quota = 1;
}
#define EDNSTOS 3U
@@ -4773,34 +4775,25 @@ dns_adb_setquota(dns_adb_t *adb, uint32_t quota, uint32_t freq,
bool
dns_adbentry_overquota(dns_adbentry_t *entry) {
REQUIRE(DNS_ADBENTRY_VALID(entry));
return (entry->quota != 0 && entry->active >= entry->quota);
uint_fast32_t quota = atomic_load_relaxed(&entry->quota);
uint_fast32_t active = atomic_load_acquire(&entry->active);
return (quota != 0 && active >= quota);
}
void
dns_adb_beginudpfetch(dns_adb_t *adb, dns_adbaddrinfo_t *addr) {
int bucket;
REQUIRE(DNS_ADB_VALID(adb));
REQUIRE(DNS_ADBADDRINFO_VALID(addr));
bucket = addr->entry->lock_bucket;
LOCK(&adb->entrylocks[bucket]);
addr->entry->active++;
UNLOCK(&adb->entrylocks[bucket]);
INSIST(atomic_fetch_add_relaxed(&addr->entry->active, 1) != UINT32_MAX);
}
void
dns_adb_endudpfetch(dns_adb_t *adb, dns_adbaddrinfo_t *addr) {
int bucket;
REQUIRE(DNS_ADB_VALID(adb));
REQUIRE(DNS_ADBADDRINFO_VALID(addr));
bucket = addr->entry->lock_bucket;
LOCK(&adb->entrylocks[bucket]);
if (addr->entry->active > 0)
addr->entry->active--;
UNLOCK(&adb->entrylocks[bucket]);
INSIST(atomic_fetch_sub_release(&addr->entry->active, 1) != 0);
}