diff options
Diffstat (limited to 'src/journal/journal-rate-limit.c')
| -rw-r--r-- | src/journal/journal-rate-limit.c | 273 |
1 files changed, 273 insertions, 0 deletions
diff --git a/src/journal/journal-rate-limit.c b/src/journal/journal-rate-limit.c new file mode 100644 index 0000000000..f69ab2770f --- /dev/null +++ b/src/journal/journal-rate-limit.c @@ -0,0 +1,273 @@ +/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ + +/*** + 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 General Public License as published by + the Free Software Foundation; either version 2 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 + General Public License for more details. + + You should have received a copy of the GNU General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include <string.h> +#include <errno.h> + +#include "journal-rate-limit.h" +#include "list.h" +#include "util.h" +#include "hashmap.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]; + unsigned 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; +}; + +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; + + 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(JournalRateLimitGroup, lru, g->parent->lru, g); + LIST_REMOVE(JournalRateLimitGroup, 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); +} + +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; + + assert(r); + assert(id); + + g = new0(JournalRateLimitGroup, 1); + if (!g) + return NULL; + + g->id = strdup(id); + if (!g->id) + goto fail; + + g->hash = string_hash_func(g->id); + + journal_rate_limit_vacuum(r, ts); + + LIST_PREPEND(JournalRateLimitGroup, bucket, r->buckets[g->hash % BUCKETS_MAX], g); + LIST_PREPEND(JournalRateLimitGroup, 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 uint64_t u64log2(uint64_t n) { + unsigned r; + + if (n <= 1) + return 0; + + r = 0; + for (;;) { + n = n >> 1; + if (!n) + return r; + r++; + } +} + +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-20)) / 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) { + unsigned h; + JournalRateLimitGroup *g; + JournalRateLimitPool *p; + 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); + + h = string_hash_func(id); + 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; +} |