diff --git a/swh/loader/git/loader.py b/swh/loader/git/loader.py
--- a/swh/loader/git/loader.py
+++ b/swh/loader/git/loader.py
@@ -8,8 +8,10 @@
 import logging
 import os
 import pickle
+import signal
 import sys
 from tempfile import SpooledTemporaryFile
+import tracemalloc
 from typing import Any, Callable, Dict, Iterable, Iterator, List, Optional, Set, Type
 
 import dulwich.client
@@ -38,6 +40,25 @@
 from .utils import HexBytes
 
 logger = logging.getLogger(__name__)
+tracemalloc_logger = logging.getLogger(__name__ + ".tracemalloc")
+
+
+def log_tracemalloc(msg: str, snapshot: tracemalloc.Snapshot):
+    top_stats = snapshot.statistics("lineno")
+
+    tracemalloc_logger.debug("[ Top 10 memory users %s ]", msg)
+    for stat in top_stats[:10]:
+        tracemalloc_logger.debug(stat)
+
+
+def log_tracemalloc_diff(
+    msg: str, snapshot1: tracemalloc.Snapshot, snapshot2: tracemalloc.Snapshot
+):
+    top_stats = snapshot2.compare_to(snapshot1, "lineno")
+
+    tracemalloc_logger.debug("[ Top 10 differences after %s ]", msg)
+    for stat in top_stats[:10]:
+        tracemalloc_logger.debug(stat)
 
 
 class RepoRepresentation:
@@ -145,6 +166,20 @@
         self.symbolic_refs: Dict[bytes, HexBytes] = {}
         self.ref_object_types: Dict[bytes, Optional[TargetType]] = {}
 
+        self.tracemalloc_snapshot = tracemalloc.take_snapshot()
+        signal.signal(signal.SIGUSR1, self.tracemalloc_handler)
+
+    def do_tracemalloc(self, msg: str):
+        tracemalloc_snapshot = tracemalloc.take_snapshot()
+        log_tracemalloc(msg, tracemalloc_snapshot)
+        log_tracemalloc_diff(
+            msg, self.tracemalloc_snapshot, tracemalloc_snapshot,
+        )
+        self.tracemalloc_snapshot = tracemalloc_snapshot
+
+    def tracemalloc_handler(self, _signum, _frame):
+        self.do_tracemalloc("on_signal")
+
     def fetch_pack_from_origin(
         self,
         origin_url: str,
@@ -216,13 +251,17 @@
         # not support it and do not fetch any refs
         self.dumb = transport_url.startswith("http") and client.dumb
 
-        return FetchPackReturn(
+        ret = FetchPackReturn(
             remote_refs=utils.filter_refs(remote_refs),
             symbolic_refs=utils.filter_refs(symbolic_refs),
             pack_buffer=pack_buffer,
             pack_size=pack_size,
         )
 
+        self.do_tracemalloc("fetch_pack_from_origins")
+
+        return ret
+
     def prepare_origin_visit(self) -> None:
         self.visit_date = datetime.datetime.now(tz=datetime.timezone.utc)
         self.origin = Origin(url=self.origin_url)
@@ -357,6 +396,8 @@
                 count += 1
             logger.debug("packfile_read_count_%s=%s", object_type.decode(), count)
 
+        self.do_tracemalloc("iter_objects")
+
     def get_contents(self) -> Iterable[BaseContent]:
         """Format the blobs from the git repository as swh contents"""
         for raw_obj in self.iter_objects(b"blob"):