[PATCH iproute2-next v2 0/3] Improve batch and dump times by caching link lookups

[David Ahern <dsahern@kernel.org>]

From: David Ahern <dsahern@gmail.com>

Many commands convert device names to an index using ll_name_to_index and
the reverse from an index to a name using ll_index_to_name.

At the moment both of the ll_ functions use the ioctl based helpers from
glibc which involves opening socket, calling ioctl and then closing the
socket on each device lookup. When using a batch file or dumping large
number of routes this means the same device lookups can be done repeatedly
adding unnecessary overhead to both operations.

This series adds a new function, ll_link_get, to send a netlink based
RTM_GETLINK. If successful, the result is cached in idx_head and name_head
so future lookups can re-use the entry. iproute2's ll_map functions are
updated to use ll_link_get over the glibc functions. The result is a
significant speed up in both batch and dumps with negligible overhead if
ip is invoked for single operations.

The first 2 patches add a means to drop an entry from the cache and updates
iplink_modify to use that new function to drop entries on device changes.
This forces the cache to re-learn device information if a batch file has a
mix of link set operations with other commands - such as adding a route.

v2
- changed the second patch to drop cache entry on any link changes
- added ll_link_get to index to name conversion improving dumps

David Ahern (3):
  ll_map: Add function to remove link cache entry by index
  ip link: Drop cache entry on any changes
  Improve batch and dump times by caching link lookups

 include/ll_map.h |  1 +
 ip/iplink.c      |  3 +++
 lib/ll_map.c     | 66 +++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 3 files changed, 69 insertions(+), 1 deletion(-)

-- 
2.11.0