[PATCH 4/4] packed-backend: use mmap when opening large "packed-refs" file
- From
shejialuo <shejialuo@gmail.com>
- Date
- May 6, 2025, 16:41 UTC
- Message-ID
- <aBo7tOkheM6zOJpe@ArchLinux>
- In-Reply-To
- <aBo7OiCKHTyT4DzH@ArchLinux>
We use "strbuf_read" to read the content of "packed-refs". However, this is a bad practice which would consume a lot of memory usage if there are multiple processes reading large "packed-refs".
As we have introduced two helper functions "allocate_snapshot_buffer" and "munmap_snapshot_if_temporary", we could simply call these functions to use mmap mechanism.
Suggested-by: Jeff King <peff@peff.net> Suggested-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: shejialuo <shejialuo@gmail.com> --- refs/packed-backend.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-)
diff --git a/refs/packed-backend.c b/refs/packed-backend.c index dd903db301..1370b982df 100644 --- a/refs/packed-backend.c +++ b/refs/packed-backend.c @@ -2074,7 +2074,7 @@ static int packed_fsck(struct ref_store *ref_store, { struct packed_ref_store *refs = packed_downcast(ref_store, REF_STORE_READ, "fsck"); - struct strbuf packed_ref_content = STRBUF_INIT; + struct snapshot *snapshot = xcalloc(1, sizeof(*snapshot)); unsigned int sorted = 0; struct stat st; int ret = 0; @@ -2121,21 +2121,21 @@ static int packed_fsck(struct ref_store *ref_store, if (!st.st_size) goto cleanup; - if (strbuf_read(&packed_ref_content, fd, 0) < 0) { - ret = error_errno(_("unable to read '%s'"), refs->path); + if (!allocate_snapshot_buffer(snapshot, fd, &st)) goto cleanup; - } + munmap_snapshot_if_temporary(snapshot); - ret = packed_fsck_ref_content(o, ref_store, &sorted, packed_ref_content.buf, - packed_ref_content.buf + packed_ref_content.len); + ret = packed_fsck_ref_content(o, ref_store, &sorted, snapshot->start, + snapshot->eof); if (!ret && sorted) - ret = packed_fsck_ref_sorted(o, ref_store, packed_ref_content.buf, - packed_ref_content.buf + packed_ref_content.len); + ret = packed_fsck_ref_sorted(o, ref_store, snapshot->start, + snapshot->eof); cleanup: if (fd >= 0) close(fd); - strbuf_release(&packed_ref_content); + clear_snapshot_buffer(snapshot); + free(snapshot); return ret; }
-- 2.49.0