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[PATCH v6 16/16] bloom: introduce `deinit_bloom_filters()`

From
Taylor Blau <me@ttaylorr.com>
Date
Jan 31, 2024, 22:53 UTC
Message-ID
<12058a074d8fa5a936f672c24943ebffc9c8ab0e.1706741516.git.me@ttaylorr.com>
In-Reply-To
<cover.1706741516.git.me@ttaylorr.com>

After we are done using Bloom filters, we do not currently clean up any memory allocated by the commit slab used to store those filters in the first place.

Besides the bloom_filter structures themselves, there is mostly nothing to free() in the first place, since in the read-only path all Bloom filter's `data` members point to a memory mapped region in the commit-graph file itself.

But when generating Bloom filters from scratch (or initializing truncated filters) we allocate additional memory to store the filter's data.

Keep track of when we need to free() this additional chunk of memory by using an extra pointer `to_free`. Most of the time this will be NULL (indicating that we are representing an existing Bloom filter stored in a memory mapped region). When it is non-NULL, free it before discarding the Bloom filters slab.

Suggested-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
---
 bloom.c        | 16 +++++++++++++++-
 bloom.h        |  3 +++
 commit-graph.c |  4 ++++
 3 files changed, 22 insertions(+), 1 deletion(-)
diff --git a/bloom.c b/bloom.c
index a1c616bc71..dbcc0f4f50 100644
--- a/bloom.c
+++ b/bloom.c
@@ -92,6 +92,7 @@ int load_bloom_filter_from_graph(struct commit_graph *g,
 					sizeof(unsigned char) * start_index +
 					BLOOMDATA_CHUNK_HEADER_SIZE);
 	filter->version = g->bloom_filter_settings->hash_version;
+	filter->to_free = NULL;
 
 	return 1;
 }
@@ -264,6 +265,18 @@ void init_bloom_filters(void)
 	init_bloom_filter_slab(&bloom_filters);
 }
 
+static void free_one_bloom_filter(struct bloom_filter *filter)
+{
+	if (!filter)
+		return;
+	free(filter->to_free);
+}
+
+void deinit_bloom_filters(void)
+{
+	deep_clear_bloom_filter_slab(&bloom_filters, free_one_bloom_filter);
+}
+
 static int pathmap_cmp(const void *hashmap_cmp_fn_data UNUSED,
 		       const struct hashmap_entry *eptr,
 		       const struct hashmap_entry *entry_or_key,
@@ -280,7 +293,7 @@ static int pathmap_cmp(const void *hashmap_cmp_fn_data UNUSED,
 static void init_truncated_large_filter(struct bloom_filter *filter,
 					int version)
 {
-	filter->data = xmalloc(1);
+	filter->data = filter->to_free = xmalloc(1);
 	filter->data[0] = 0xFF;
 	filter->len = 1;
 	filter->version = version;
@@ -482,6 +495,7 @@ struct bloom_filter *get_or_compute_bloom_filter(struct repository *r,
 			filter->len = 1;
 		}
 		CALLOC_ARRAY(filter->data, filter->len);
+		filter->to_free = filter->data;
 
 		hashmap_for_each_entry(&pathmap, &iter, e, entry) {
 			struct bloom_key key;
diff --git a/bloom.h b/bloom.h
index e3a9b68905..d20e64bfbb 100644
--- a/bloom.h
+++ b/bloom.h
@@ -56,6 +56,8 @@ struct bloom_filter {
 	unsigned char *data;
 	size_t len;
 	int version;
+
+	void *to_free;
 };
 
 /*
@@ -96,6 +98,7 @@ void add_key_to_filter(const struct bloom_key *key,
 		       const struct bloom_filter_settings *settings);
 
 void init_bloom_filters(void);
+void deinit_bloom_filters(void);
 
 enum bloom_filter_computed {
 	BLOOM_NOT_COMPUTED = (1 << 0),
diff --git a/commit-graph.c b/commit-graph.c
index 320ac856ca..6f5f8f158f 100644
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -831,6 +831,7 @@ void close_commit_graph(struct raw_object_store *o)
 		return;
 
 	clear_commit_graph_data_slab(&commit_graph_data_slab);
+	deinit_bloom_filters();
 	free_commit_graph(o->commit_graph);
 	o->commit_graph = NULL;
 }
@@ -2649,6 +2650,9 @@ int write_commit_graph(struct object_directory *odb,
 
 	res = write_commit_graph_file(ctx);
 
+	if (ctx->changed_paths)
+		deinit_bloom_filters();
+
 	if (ctx->split)
 		mark_commit_graphs(ctx);
 
-- 
2.43.0.509.g253f65a7fc
Previous: Taylor BlauNext: Taylor Blau
Message 19 of 36 in “bloom: changed-path Bloom filters v2 (& sundries)”
  1. 00/16 bloom: changed-path Bloom filters v2 (& sundries)Taylor Blau, Jan 31, 2024
  2. 01/16 t/t4216-log-bloom.sh: harden `test_bloom_filters_not_used()`Taylor Blau, Jan 31, 2024
  3. 02/16 revision.c: consult Bloom filters for root commitsTaylor Blau, Jan 31, 2024
  4. 03/16 commit-graph: ensure Bloom filters are read with consistent settingsTaylor Blau, Jan 31, 2024
  5. 04/16 gitformat-commit-graph: describe version 2 of BDATTaylor Blau, Jan 31, 2024
  6. 05/16 t/helper/test-read-graph.c: extract `dump_graph_info()`Taylor Blau, Jan 31, 2024
  7. 06/16 bloom.h: make `load_bloom_filter_from_graph()` publicTaylor Blau, Jan 31, 2024
  8. 07/16 t/helper/test-read-graph: implement `bloom-filters` modeTaylor Blau, Jan 31, 2024
  9. 08/16 t4216: test changed path filters with high bit pathsTaylor Blau, Jan 31, 2024
  10. 09/16 repo-settings: introduce commitgraph.changedPathsVersionTaylor Blau, Jan 31, 2024
  11. 10/16 bloom: annotate filters with hash versionTaylor Blau, Jan 31, 2024
  12. 11/16 bloom: prepare to discard incompatible Bloom filtersTaylor Blau, Jan 31, 2024
  13. 12/16 commit-graph: unconditionally load Bloom filtersTaylor Blau, Jan 31, 2024
  14. 13/16 commit-graph: new Bloom filter version that fixes murmur3Taylor Blau, Jan 31, 2024
  15. SZEDER GáborFeb 25, 2024
  16. Jiang XinFeb 28, 2024
  17. 14/16 object.h: fix mis-aligned flag bits tableTaylor Blau, Jan 31, 2024
  18. 15/16 commit-graph: reuse existing Bloom filters where possibleTaylor Blau, Jan 31, 2024
  19. 16/16 bloom: introduce `deinit_bloom_filters()`Taylor Blau, Jan 31, 2024
  20. 00/16 bloom: changed-path Bloom filters v2 (& sundries)Taylor Blau, Jun 25, 2024
  21. 01/16 t/t4216-log-bloom.sh: harden `test_bloom_filters_not_used()`Taylor Blau, Jun 25, 2024
  22. 02/16 revision.c: consult Bloom filters for root commitsTaylor Blau, Jun 25, 2024
  23. 03/16 commit-graph: ensure Bloom filters are read with consistent settingsTaylor Blau, Jun 25, 2024
  24. 04/16 gitformat-commit-graph: describe version 2 of BDATTaylor Blau, Jun 25, 2024
  25. 05/16 t/helper/test-read-graph.c: extract `dump_graph_info()`Taylor Blau, Jun 25, 2024
  26. 06/16 bloom.h: make `load_bloom_filter_from_graph()` publicTaylor Blau, Jun 25, 2024
  27. 07/16 t/helper/test-read-graph: implement `bloom-filters` modeTaylor Blau, Jun 25, 2024
  28. 08/16 t4216: test changed path filters with high bit pathsTaylor Blau, Jun 25, 2024
  29. 09/16 repo-settings: introduce commitgraph.changedPathsVersionTaylor Blau, Jun 25, 2024
  30. 10/16 bloom: annotate filters with hash versionTaylor Blau, Jun 25, 2024
  31. 11/16 bloom: prepare to discard incompatible Bloom filtersTaylor Blau, Jun 25, 2024
  32. 12/16 commit-graph: unconditionally load Bloom filtersTaylor Blau, Jun 25, 2024
  33. 13/16 commit-graph: new Bloom filter version that fixes murmur3Taylor Blau, Jun 25, 2024
  34. 14/16 object.h: fix mis-aligned flag bits tableTaylor Blau, Jun 25, 2024
  35. 15/16 commit-graph: reuse existing Bloom filters where possibleTaylor Blau, Jun 25, 2024
  36. 16/16 bloom: introduce `deinit_bloom_filters()`Taylor Blau, Jun 25, 2024

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