commit 37aae23945c45c459091b38699130a14466d33ef Author: Nick Mathewson nickm@torproject.org Date: Fri May 17 10:03:41 2019 -0400

OOM-purge the DNS cache one part at a time

Previously we purged it in 1-hour increments -- but one-hour is the maximum TTL for the cache! Now we do it in 25%-TTL increments.

Fixes bug 29617; bugfix on 0.3.5.1-alpha. --- changes/ticket29617 | 4 ++++ src/feature/relay/dns.c | 3 ++- 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/changes/ticket29617 b/changes/ticket29617 new file mode 100644 index 000000000..4d50ea962 --- /dev/null +++ b/changes/ticket29617 @@ -0,0 +1,4 @@ + o Minor bugfixes (out-of-memory handler): + - When purging the DNS cache because of an out-of-memory condition, + try purging just the older entries at first. Previously, we would + purge the whole thing. Fixes bug 29617; bugfix on 0.3.5.1-alpha. diff --git a/src/feature/relay/dns.c b/src/feature/relay/dns.c index d3660c47e..cc9f4cf49 100644 --- a/src/feature/relay/dns.c +++ b/src/feature/relay/dns.c @@ -2130,7 +2130,8 @@ dns_cache_handle_oom(time_t now, size_t min_remove_bytes) current_size -= bytes_removed; total_bytes_removed += bytes_removed;

- time_inc += 3600; /* Increase time_inc by 1 hour. */ + /* Increase time_inc by a reasonable fraction. */ + time_inc += (MAX_DNS_TTL_AT_EXIT / 4); } while (total_bytes_removed < min_remove_bytes);

return total_bytes_removed;