When decoding a log record we always reallocate their refname arrays.
This results in quite a lot of needless allocation churn.
Refactor the code to grow the array as required only. Like this, we
should usually only end up reallocating the array a small handful of
times when iterating over many refs. Before:
HEAP SUMMARY:
in use at exit: 13,473 bytes in 122 blocks
total heap usage: 4,068,487 allocs, 4,068,365 frees, 332,011,793 bytes allocated
After:
HEAP SUMMARY:
in use at exit: 13,473 bytes in 122 blocks
total heap usage: 3,068,488 allocs, 3,068,366 frees, 307,122,961 bytes allocated
Signed-off-by: Patrick Steinhardt <ps@xxxxxx>
---
reftable/record.c | 2 +-
reftable/reftable-record.h | 1 +
2 files changed, 2 insertions(+), 1 deletion(-)
diff --git a/reftable/record.c b/reftable/record.c
index d816de6d93..82780b2d06 100644
--- a/reftable/record.c
+++ b/reftable/record.c
@@ -861,7 +861,7 @@ static int reftable_log_record_decode(void *rec, struct strbuf key,
if (key.len <= 9 || key.buf[key.len - 9] != 0)
return REFTABLE_FORMAT_ERROR;
- r->refname = reftable_realloc(r->refname, key.len - 8);
+ REFTABLE_ALLOC_GROW(r->refname, key.len - 8, r->refname_cap);
memcpy(r->refname, key.buf, key.len - 8);
ts = get_be64(key.buf + key.len - 8);
diff --git a/reftable/reftable-record.h b/reftable/reftable-record.h
index 2659ea008c..d28f38175c 100644
--- a/reftable/reftable-record.h
+++ b/reftable/reftable-record.h
@@ -74,6 +74,7 @@ int reftable_ref_record_equal(const struct reftable_ref_record *a,
/* reftable_log_record holds a reflog entry */
struct reftable_log_record {
char *refname;
+ size_t refname_cap;
uint64_t update_index; /* logical timestamp of a transactional update.
*/
--
2.44.0
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