context: reduce the size of LOGICAL_INO buffers

Since we'll never process more than BEES_MAX_EXTENT_REF_COUNT extent references by definition, it follows that we should not allocate buffer space for them when we perform the LOGICAL_INO ioctl. There is some evidence (particularly #260 (comment)) that the kernel is subjecting the page cache to a lot of disruption when trying allocate large buffers for LOGICAL_INO. Signed-off-by: Zygo Blaxell <[email protected]>
Zygo · Apr 18, 2024 · 75131f3 · 75131f3
1 parent cfb7592
commit 75131f3
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/src/bees-context.cc b/src/bees-context.cc
@@ -925,7 +925,8 @@ BeesContext::start()
 		return make_shared<BeesTempFile>(shared_from_this());
 	});
 	m_logical_ino_pool.generator([]() {
-		return make_shared<BtrfsIoctlLogicalInoArgs>(0);
+		const auto extent_ref_size = sizeof(uint64_t) * 3;
+		return make_shared<BtrfsIoctlLogicalInoArgs>(0, BEES_MAX_EXTENT_REF_COUNT * extent_ref_size + sizeof(btrfs_data_container));
 	});
 	m_tmpfile_pool.checkin([](const shared_ptr<BeesTempFile> &btf) {
 		catch_all([&](){