Re: [PATCH v4] net: sched: convert qdisc linked list to hashtable

From: Cong Wang
Date: Thu Jul 28 2016 - 12:53:30 EST

On Thu, Jul 28, 2016 at 2:56 AM, Jiri Kosina <jikos@xxxxxxxxxx> wrote:
> From: Jiri Kosina <jkosina@xxxxxxx>
> Convert the per-device linked list into a hashtable. The primary
> motivation for this change is that currently, we're not tracking all the
> qdiscs in hierarchy (e.g. excluding default qdiscs), as the lookup
> performed over the linked list by qdisc_match_from_root() is rather
> expensive.
> The ultimate goal is to get rid of hidden qdiscs completely, which will
> bring much more determinism in user experience.
> As we're adding hashtable.h include into generic netdevice.h, we have to
> make sure HASH_SIZE macro is now non-conflicting with local definitions.
> Signed-off-by: Jiri Kosina <jkosina@xxxxxxx>
> ---
> v1 -> v2: fix up RCU hastable usage wrt. rtnl
> fix compilation of .c files which define their own
> HASH_SIZE that now oncflicts with the one from
> hashtable.h (newly included via netdevice.h)
> v2 -> v3: resolve HASH_SIZE identifier conflicts in a cleaner way
> fix up the number of hash bucket bits (4 bits for 16 buckets)
> v3 -> v4: put the hastable into struct netdevice only if
> CONFIG_NET_SCHED has been enabled

Reviewed-by: Cong Wang <xiyou.wangcong@xxxxxxxxx>