diff options
Diffstat (limited to 'src/grp-journal/libjournal-core/src/journald-rate-limit.c')
| -rw-r--r-- | src/grp-journal/libjournal-core/src/journald-rate-limit.c | 271 |
1 files changed, 271 insertions, 0 deletions
diff --git a/src/grp-journal/libjournal-core/src/journald-rate-limit.c b/src/grp-journal/libjournal-core/src/journald-rate-limit.c new file mode 100644 index 0000000000..10bff9df83 --- /dev/null +++ b/src/grp-journal/libjournal-core/src/journald-rate-limit.c @@ -0,0 +1,271 @@ +/*** + This file is part of systemd. + + Copyright 2011 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include <errno.h> +#include <string.h> + +#include "journal-core/journald-rate-limit.h" +#include "systemd-basic/alloc-util.h" +#include "systemd-basic/hashmap.h" +#include "systemd-basic/list.h" +#include "systemd-basic/random-util.h" +#include "systemd-basic/string-util.h" +#include "systemd-basic/util.h" + +#define POOLS_MAX 5 +#define BUCKETS_MAX 127 +#define GROUPS_MAX 2047 + +static const int priority_map[] = { + [LOG_EMERG] = 0, + [LOG_ALERT] = 0, + [LOG_CRIT] = 0, + [LOG_ERR] = 1, + [LOG_WARNING] = 2, + [LOG_NOTICE] = 3, + [LOG_INFO] = 3, + [LOG_DEBUG] = 4 +}; + +typedef struct JournalRateLimitPool JournalRateLimitPool; +typedef struct JournalRateLimitGroup JournalRateLimitGroup; + +struct JournalRateLimitPool { + usec_t begin; + unsigned num; + unsigned suppressed; +}; + +struct JournalRateLimitGroup { + JournalRateLimit *parent; + + char *id; + JournalRateLimitPool pools[POOLS_MAX]; + uint64_t hash; + + LIST_FIELDS(JournalRateLimitGroup, bucket); + LIST_FIELDS(JournalRateLimitGroup, lru); +}; + +struct JournalRateLimit { + usec_t interval; + unsigned burst; + + JournalRateLimitGroup* buckets[BUCKETS_MAX]; + JournalRateLimitGroup *lru, *lru_tail; + + unsigned n_groups; + + uint8_t hash_key[16]; +}; + +JournalRateLimit *journal_rate_limit_new(usec_t interval, unsigned burst) { + JournalRateLimit *r; + + assert(interval > 0 || burst == 0); + + r = new0(JournalRateLimit, 1); + if (!r) + return NULL; + + r->interval = interval; + r->burst = burst; + + random_bytes(r->hash_key, sizeof(r->hash_key)); + + return r; +} + +static void journal_rate_limit_group_free(JournalRateLimitGroup *g) { + assert(g); + + if (g->parent) { + assert(g->parent->n_groups > 0); + + if (g->parent->lru_tail == g) + g->parent->lru_tail = g->lru_prev; + + LIST_REMOVE(lru, g->parent->lru, g); + LIST_REMOVE(bucket, g->parent->buckets[g->hash % BUCKETS_MAX], g); + + g->parent->n_groups--; + } + + free(g->id); + free(g); +} + +void journal_rate_limit_free(JournalRateLimit *r) { + assert(r); + + while (r->lru) + journal_rate_limit_group_free(r->lru); + + free(r); +} + +_pure_ static bool journal_rate_limit_group_expired(JournalRateLimitGroup *g, usec_t ts) { + unsigned i; + + assert(g); + + for (i = 0; i < POOLS_MAX; i++) + if (g->pools[i].begin + g->parent->interval >= ts) + return false; + + return true; +} + +static void journal_rate_limit_vacuum(JournalRateLimit *r, usec_t ts) { + assert(r); + + /* Makes room for at least one new item, but drop all + * expored items too. */ + + while (r->n_groups >= GROUPS_MAX || + (r->lru_tail && journal_rate_limit_group_expired(r->lru_tail, ts))) + journal_rate_limit_group_free(r->lru_tail); +} + +static JournalRateLimitGroup* journal_rate_limit_group_new(JournalRateLimit *r, const char *id, usec_t ts) { + JournalRateLimitGroup *g; + struct siphash state; + + assert(r); + assert(id); + + g = new0(JournalRateLimitGroup, 1); + if (!g) + return NULL; + + g->id = strdup(id); + if (!g->id) + goto fail; + + siphash24_init(&state, r->hash_key); + string_hash_func(g->id, &state); + g->hash = siphash24_finalize(&state); + + journal_rate_limit_vacuum(r, ts); + + LIST_PREPEND(bucket, r->buckets[g->hash % BUCKETS_MAX], g); + LIST_PREPEND(lru, r->lru, g); + if (!g->lru_next) + r->lru_tail = g; + r->n_groups++; + + g->parent = r; + return g; + +fail: + journal_rate_limit_group_free(g); + return NULL; +} + +static unsigned burst_modulate(unsigned burst, uint64_t available) { + unsigned k; + + /* Modulates the burst rate a bit with the amount of available + * disk space */ + + k = u64log2(available); + + /* 1MB */ + if (k <= 20) + return burst; + + burst = (burst * (k-16)) / 4; + + /* + * Example: + * + * <= 1MB = rate * 1 + * 16MB = rate * 2 + * 256MB = rate * 3 + * 4GB = rate * 4 + * 64GB = rate * 5 + * 1TB = rate * 6 + */ + + return burst; +} + +int journal_rate_limit_test(JournalRateLimit *r, const char *id, int priority, uint64_t available) { + uint64_t h; + JournalRateLimitGroup *g; + JournalRateLimitPool *p; + struct siphash state; + unsigned burst; + usec_t ts; + + assert(id); + + if (!r) + return 1; + + if (r->interval == 0 || r->burst == 0) + return 1; + + burst = burst_modulate(r->burst, available); + + ts = now(CLOCK_MONOTONIC); + + siphash24_init(&state, r->hash_key); + string_hash_func(id, &state); + h = siphash24_finalize(&state); + g = r->buckets[h % BUCKETS_MAX]; + + LIST_FOREACH(bucket, g, g) + if (streq(g->id, id)) + break; + + if (!g) { + g = journal_rate_limit_group_new(r, id, ts); + if (!g) + return -ENOMEM; + } + + p = &g->pools[priority_map[priority]]; + + if (p->begin <= 0) { + p->suppressed = 0; + p->num = 1; + p->begin = ts; + return 1; + } + + if (p->begin + r->interval < ts) { + unsigned s; + + s = p->suppressed; + p->suppressed = 0; + p->num = 1; + p->begin = ts; + + return 1 + s; + } + + if (p->num < burst) { + p->num++; + return 1; + } + + p->suppressed++; + return 0; +} |