X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=src%2Fjournal%2Fjournal-rate-limit.c;fp=src%2Fjournal%2Fjournal-rate-limit.c;h=f69ab2770f72e74dad611f8f5be3a1d6fd349e01;hb=6e409ce10d134625626d1eddfd6152755ef1908d;hp=0000000000000000000000000000000000000000;hpb=fe6521272ba203ec8f0d5a94f0729960b3f90525;p=elogind.git
diff --git a/src/journal/journal-rate-limit.c b/src/journal/journal-rate-limit.c
new file mode 100644
index 000000000..f69ab2770
--- /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 .
+***/
+
+#include
+#include
+
+#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;
+}