enhanced items_delete_batch() in Python to avoid double list creation

This commit enhances the items_delete_batch() function by accepting a ct.Array instead of a Python list.
This way, the array does not need to be re-created, allowing to directly perform the requested operation.

Signed-off-by: Simone Magnani <[email protected]>

src/python/bcc/table.py

@@ -428,26 +428,23 @@ def items_delete_batch(self, keys=None):
  """Delete all the key-value pairs in the map if no key are given.
  In that case, it is faster to call lib.bpf_lookup_and_delete_batch than
  create keys list and then call lib.bpf_delete_batch on these keys.
- If a list of keys is given then it deletes the related key-value.
+ If the array of keys is given then it deletes the related key-value.
  """
  if keys is not None:
- # a list is expected
- if type(keys) != list:
+ # a ct.Array is expected
+ if not isinstance(keys, ct.Array):
  raise TypeError
 
  batch_size = len(keys)
- if batch_size < 1 and batch_size > self.max_entries:
+
+ # check that batch between limits and coherent with the provided values
+ if batch_size < 1 or batch_size > self.max_entries:
  raise KeyError
 
  count = ct.c_uint32(batch_size)
 
- # build the array aka list of key_t that will be deleted
- keylist = (type(self.Key()) * batch_size)()
- for i, k in enumerate(keys):
- keylist[i] = k
-
  res = lib.bpf_delete_batch(self.map_fd,
- ct.byref(keylist),
+ ct.byref(keys),
  ct.byref(count)
  )
  errcode = ct.get_errno()

tests/python/test_map_batch_ops.py

@@ -81,9 +81,9 @@ def test_delete_batch_subset(self):
  hmap = self.fill_hashmap()
  # Get 4 keys in this map.
  subset_size = 32
- keys = [None] * subset_size
+ keys = (hmap.Key * subset_size)()
  i = 0
- for k, v in hmap.items_lookup_batch():
+ for k, _ in hmap.items_lookup_batch():
  if i < subset_size:
  keys[i] = k
  i += 1