From 93d05d4a320cb16712bb3d57a9658f395d8cecb9 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 18 Nov 2015 06:31:03 -0800 Subject: net: provide generic busy polling to all NAPI drivers NAPI drivers no longer need to observe a particular protocol to benefit from busy polling (CONFIG_NET_RX_BUSY_POLL=y) napi_hash_add() and napi_hash_del() are automatically called from core networking stack, respectively from netif_napi_add() and netif_napi_del() This patch depends on free_netdev() and netif_napi_del() being called from process context, which seems to be the norm. Drivers might still prefer to call napi_hash_del() on their own, since they might combine all the rcu grace periods into a single one, knowing their NAPI structures lifetime, while core networking stack has no idea of a possible combining. Once this patch proves to not bring serious regressions, we will cleanup drivers to either remove napi_hash_del() or provide appropriate rcu grace periods combining. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- include/linux/netdevice.h | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'include/linux') diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index e5c33b29471b..7d2d1d7aaec7 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -466,6 +466,9 @@ static inline void napi_complete(struct napi_struct *n) * @napi: napi context * * generate a new napi_id and store a @napi under it in napi_hash + * Used for busy polling (CONFIG_NET_RX_BUSY_POLL) + * Note: This is normally automatically done from netif_napi_add(), + * so might disappear in a future linux version. */ void napi_hash_add(struct napi_struct *napi); @@ -476,6 +479,10 @@ void napi_hash_add(struct napi_struct *napi); * Warning: caller must observe rcu grace period * before freeing memory containing @napi, if * this function returns true. + * Note: core networking stack automatically calls it + * from netif_napi_del() + * Drivers might want to call this helper to combine all + * the needed rcu grace periods into a single one. */ bool napi_hash_del(struct napi_struct *napi); -- cgit v1.2.3