Use smaller zlib objects when under memory pressure

We add a compression level argument to tor_zlib_new, and use it to
determine how much memory to allocate for the zlib object.  We use the
existing level by default, but shift to smaller levels for small
requests when we have been over 3/4 of our memory usage in the past
half-hour.

Closes ticket 11791.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/test/test_buffers.c b/src/test/test_buffers.c
index cb29ab0a9e..e24aa8ec86 100644
--- a/src/test/test_buffers.c
+++ b/src/test/test_buffers.c
@@ -611,7 +611,7 @@ test_buffers_zlib_impl(int finalize_with_nil)
   int done;
 
   buf = buf_new_with_capacity(128); /* will round up */
-  zlib_state = tor_zlib_new(1, ZLIB_METHOD);
+  zlib_state = tor_zlib_new(1, ZLIB_METHOD, HIGH_COMPRESSION);
 
   msg = tor_malloc(512);
   crypto_rand(msg, 512);
@@ -688,7 +688,7 @@ test_buffers_zlib_fin_at_chunk_end(void *arg)
   tt_uint_op(buf->head->datalen, OP_EQ, headerjunk);
   tt_uint_op(buf_datalen(buf), OP_EQ, headerjunk);
   /* Write an empty string, with finalization on. */
-  zlib_state = tor_zlib_new(1, ZLIB_METHOD);
+  zlib_state = tor_zlib_new(1, ZLIB_METHOD, HIGH_COMPRESSION);
   tt_int_op(write_to_buf_zlib(buf, zlib_state, "", 0, 1), OP_EQ, 0);
 
   in_len = buf_datalen(buf);