This patch adds the possibility to set the busy poll budget to
something else than 8 in napi_busy_loop. All the current users of
napi_busy_loop will still have a budget of 8, but the for the XDP
socket busy poll support, we need to have a configurable budget that
is usually larger since each packet requires less processing than with
an AF_INET socket.
Signed-off-by: Magnus Karlsson <magnus.karlsson@xxxxxxxxx>
---
fs/eventpoll.c | 5 ++++-
include/net/busy_poll.h | 7 +++++--
net/core/dev.c | 21 ++++++++++-----------
3 files changed, 19 insertions(+), 14 deletions(-)
diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 4a0e98d..0fbbc35 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -394,6 +394,8 @@ static bool ep_busy_loop_end(void *p, unsigned long start_time)
return ep_events_available(ep) || busy_loop_timeout(start_time);
}
+#define BUSY_POLL_BUDGET 8
+
/*
* Busy poll if globally on and supporting sockets found && no events,
* busy loop will return if need_resched or ep_events_available.
@@ -405,7 +407,8 @@ static void ep_busy_loop(struct eventpoll *ep, int nonblock)
unsigned int napi_id = READ_ONCE(ep->napi_id);
if ((napi_id >= MIN_NAPI_ID) && net_busy_loop_on())
- napi_busy_loop(napi_id, nonblock ? NULL : ep_busy_loop_end, ep);
+ napi_busy_loop(napi_id, nonblock ? NULL : ep_busy_loop_end, ep,
+ BUSY_POLL_BUDGET);
}
static inline void ep_reset_busy_poll_napi_id(struct eventpoll *ep)
diff --git a/include/net/busy_poll.h b/include/net/busy_poll.h
index ba61cdd..94817e8 100644
--- a/include/net/busy_poll.h
+++ b/include/net/busy_poll.h
@@ -55,7 +55,7 @@ bool sk_busy_loop_end(void *p, unsigned long start_time);
void napi_busy_loop(unsigned int napi_id,
bool (*loop_end)(void *, unsigned long),
- void *loop_end_arg);
+ void *loop_end_arg, int budget);
#else /* CONFIG_NET_RX_BUSY_POLL */
static inline unsigned long net_busy_loop_on(void)
@@ -111,13 +111,16 @@ static inline bool sk_busy_loop_timeout(struct sock *sk,
return true;
}
+#define BUSY_POLL_BUDGET 8
+
static inline void sk_busy_loop(struct sock *sk, int nonblock)
{
#ifdef CONFIG_NET_RX_BUSY_POLL
unsigned int napi_id = READ_ONCE(sk->sk_napi_id);
if (napi_id >= MIN_NAPI_ID)
- napi_busy_loop(napi_id, nonblock ? NULL : sk_busy_loop_end, sk);
+ napi_busy_loop(napi_id, nonblock ? NULL : sk_busy_loop_end, sk,
+ BUSY_POLL_BUDGET);
#endif
}
diff --git a/net/core/dev.c b/net/core/dev.c
index 22f2640..e82fc44 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -6108,9 +6108,8 @@ static struct napi_struct *napi_by_id(unsigned int napi_id)
#if defined(CONFIG_NET_RX_BUSY_POLL)
-#define BUSY_POLL_BUDGET 8
-
-static void busy_poll_stop(struct napi_struct *napi, void *have_poll_lock)
+static void busy_poll_stop(struct napi_struct *napi, void *have_poll_lock,
+ int budget)
{
int rc;
@@ -6131,17 +6130,17 @@ static void busy_poll_stop(struct napi_struct *napi, void *have_poll_lock)
/* All we really want here is to re-enable device interrupts.
* Ideally, a new ndo_busy_poll_stop() could avoid another round.
*/
- rc = napi->poll(napi, BUSY_POLL_BUDGET);
- trace_napi_poll(napi, rc, BUSY_POLL_BUDGET);
+ rc = napi->poll(napi, budget);
+ trace_napi_poll(napi, rc, budget);
netpoll_poll_unlock(have_poll_lock);
- if (rc == BUSY_POLL_BUDGET)
+ if (rc == budget)
__napi_schedule(napi);
local_bh_enable();
}
void napi_busy_loop(unsigned int napi_id,
bool (*loop_end)(void *, unsigned long),
- void *loop_end_arg)
+ void *loop_end_arg, int budget)
{
unsigned long start_time = loop_end ? busy_loop_current_time() : 0;
int (*napi_poll)(struct napi_struct *napi, int budget);
@@ -6178,8 +6177,8 @@ void napi_busy_loop(unsigned int napi_id,
have_poll_lock = netpoll_poll_lock(napi);
napi_poll = napi->poll;
}
- work = napi_poll(napi, BUSY_POLL_BUDGET);
- trace_napi_poll(napi, work, BUSY_POLL_BUDGET);
+ work = napi_poll(napi, budget);
+ trace_napi_poll(napi, work, budget);
count:
if (work > 0)
__NET_ADD_STATS(dev_net(napi->dev),
@@ -6191,7 +6190,7 @@ void napi_busy_loop(unsigned int napi_id,
if (unlikely(need_resched())) {
if (napi_poll)
- busy_poll_stop(napi, have_poll_lock);
+ busy_poll_stop(napi, have_poll_lock, budget);
preempt_enable();
rcu_read_unlock();
cond_resched();
@@ -6202,7 +6201,7 @@ void napi_busy_loop(unsigned int napi_id,
cpu_relax();
}
if (napi_poll)
- busy_poll_stop(napi, have_poll_lock);
+ busy_poll_stop(napi, have_poll_lock, budget);
preempt_enable();
out:
rcu_read_unlock();
--
2.7.4
