commit 32db806dfa85b016a2d56d0d5248f17c34b690c4 Author: Neel Chauhan neel@neelc.org Date: Mon Jul 16 17:36:22 2018 -0400
Teach the OOM handler about the DNS cache --- src/core/or/relay.c | 7 +++++++ src/feature/relay/dns.c | 30 ++++++++++++++++++++++++++++++ src/feature/relay/dns.h | 1 + 3 files changed, 38 insertions(+)
diff --git a/src/core/or/relay.c b/src/core/or/relay.c index 32bb69d25..62a4bca84 100644 --- a/src/core/or/relay.c +++ b/src/core/or/relay.c @@ -64,6 +64,7 @@ #include "lib/crypt_ops/crypto_rand.h" #include "lib/crypt_ops/crypto_util.h" #include "feature/dircache/directory.h" +#include "feature/relay/dns.h" #include "feature/stats/geoip.h" #include "feature/hs/hs_cache.h" #include "core/mainloop/main.h" @@ -2537,6 +2538,7 @@ cell_queues_check_size(void) const size_t geoip_client_cache_total = geoip_client_cache_total_allocation(); alloc += geoip_client_cache_total; + const size_t dns_cache_total = dns_cache_total_allocation(); if (alloc >= get_options()->MaxMemInQueues_low_threshold) { last_time_under_memory_pressure = approx_time(); if (alloc >= get_options()->MaxMemInQueues) { @@ -2554,6 +2556,11 @@ cell_queues_check_size(void) (size_t)(get_options()->MaxMemInQueues / 10); alloc -= geoip_client_cache_handle_oom(now, bytes_to_remove); } + if (dns_cache_total > get_options()->MaxMemInQueues / 5) { + const size_t bytes_to_remove = + dns_cache_total - (size_t)(get_options()->MaxMemInQueues / 10); + alloc -= dns_cache_handle_oom(now, bytes_to_remove); + } circuits_handle_oom(alloc); return 1; } diff --git a/src/feature/relay/dns.c b/src/feature/relay/dns.c index 8a49829d5..48319b47c 100644 --- a/src/feature/relay/dns.c +++ b/src/feature/relay/dns.c @@ -2100,6 +2100,36 @@ dump_dns_mem_usage(int severity) (unsigned)hash_mem); }
+/* Do a round of OOM cleanup on all DNS entries. Return the amount of removed + * bytes. It is possible that the returned value is lower than min_remove_bytes + * if the caches get emptied out so the caller should be aware of this. */ +size_t +dns_cache_handle_oom(time_t now, size_t min_remove_bytes) +{ + time_t time_inc = 0; + size_t total_bytes_removed = 0; + size_t current_size = dns_cache_total_allocation(); + + do { + /* If no DNS entries left, break loop. */ + if (!dns_cache_entry_count()) + break; + + /* Get cutoff interval and remove entries. */ + time_t cutoff = now + time_inc; + purge_expired_resolves(cutoff); + + /* Update amount of bytes removed and array size. */ + size_t bytes_removed = current_size - dns_cache_total_allocation(); + current_size -= bytes_removed; + total_bytes_removed += bytes_removed; + + time_inc += 3600; /* Increase time_inc by 1 hour. */ + } while (total_bytes_removed < min_remove_bytes); + + return total_bytes_removed; +} + #ifdef DEBUG_DNS_CACHE /** Exit with an assertion if the DNS cache is corrupt. */ static void diff --git a/src/feature/relay/dns.h b/src/feature/relay/dns.h index 1d5266c73..1dd6f903d 100644 --- a/src/feature/relay/dns.h +++ b/src/feature/relay/dns.h @@ -40,6 +40,7 @@ int dns_seems_to_be_broken_for_ipv6(void); void dns_reset_correctness_checks(void); size_t dns_cache_total_allocation(void); void dump_dns_mem_usage(int severity); +size_t dns_cache_handle_oom(time_t now, size_t min_remove_bytes);
#ifdef DNS_PRIVATE #include "feature/relay/dns_structs.h"