diff mbox series

[RFC,bpf-next,2/9] net: add SO_BUSY_POLL_BUDGET socket option

Message ID 20201028133437.212503-3-bjorn.topel@gmail.com (mailing list archive)
State RFC
Delegated to: BPF
Headers show
Series Introduce biased busy-polling | expand

Commit Message

Björn Töpel Oct. 28, 2020, 1:34 p.m. UTC 
From: Björn Töpel <bjorn.topel@intel.com>

This option lets a user set a per socket NAPI budget for
busy-polling. If the options is not set, it will use the default of 8.

Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
---
 arch/alpha/include/uapi/asm/socket.h  |  1 +
 arch/mips/include/uapi/asm/socket.h   |  1 +
 arch/parisc/include/uapi/asm/socket.h |  1 +
 arch/sparc/include/uapi/asm/socket.h  |  1 +
 fs/eventpoll.c                        |  3 ++-
 include/net/busy_poll.h               |  6 ++++--
 include/net/sock.h                    |  1 +
 include/uapi/asm-generic/socket.h     |  1 +
 net/core/dev.c                        | 20 +++++++++-----------
 net/core/sock.c                       | 10 ++++++++++
 10 files changed, 31 insertions(+), 14 deletions(-)
diff mbox series

Patch

diff --git a/arch/alpha/include/uapi/asm/socket.h b/arch/alpha/include/uapi/asm/socket.h
index 0f776668fb09..4ea972b7b711 100644
--- a/arch/alpha/include/uapi/asm/socket.h
+++ b/arch/alpha/include/uapi/asm/socket.h
@@ -125,6 +125,7 @@ 
 #define SO_DETACH_REUSEPORT_BPF 68
 
 #define SO_BIAS_BUSY_POLL	69
+#define SO_BUSY_POLL_BUDGET	70
 
 #if !defined(__KERNEL__)
 
diff --git a/arch/mips/include/uapi/asm/socket.h b/arch/mips/include/uapi/asm/socket.h
index d23984731504..13eaffbfbe50 100644
--- a/arch/mips/include/uapi/asm/socket.h
+++ b/arch/mips/include/uapi/asm/socket.h
@@ -136,6 +136,7 @@ 
 #define SO_DETACH_REUSEPORT_BPF 68
 
 #define SO_BIAS_BUSY_POLL	69
+#define SO_BUSY_POLL_BUDGET	70
 
 #if !defined(__KERNEL__)
 
diff --git a/arch/parisc/include/uapi/asm/socket.h b/arch/parisc/include/uapi/asm/socket.h
index 49469713ed2a..036e42dac6b3 100644
--- a/arch/parisc/include/uapi/asm/socket.h
+++ b/arch/parisc/include/uapi/asm/socket.h
@@ -117,6 +117,7 @@ 
 #define SO_DETACH_REUSEPORT_BPF 0x4042
 
 #define SO_BIAS_BUSY_POLL	0x4043
+#define SO_BUSY_POLL_BUDGET	0x4044
 
 #if !defined(__KERNEL__)
 
diff --git a/arch/sparc/include/uapi/asm/socket.h b/arch/sparc/include/uapi/asm/socket.h
index 009aba6f7a54..bc482dc93bd4 100644
--- a/arch/sparc/include/uapi/asm/socket.h
+++ b/arch/sparc/include/uapi/asm/socket.h
@@ -118,6 +118,7 @@ 
 #define SO_DETACH_REUSEPORT_BPF  0x0047
 
 #define SO_BIAS_BUSY_POLL	 0x0048
+#define SO_BUSY_POLL_BUDGET	 0x0049
 
 #if !defined(__KERNEL__)
 
diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 4df61129566d..fa00a0640264 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -397,7 +397,8 @@  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 9738923ed17b..c6c413d3824d 100644
--- a/include/net/busy_poll.h
+++ b/include/net/busy_poll.h
@@ -25,6 +25,7 @@ 
 
 /* Biased busy-poll watchdog timeout in ms */
 #define BIASED_BUSY_POLL_TIMEOUT 200
+#define BUSY_POLL_BUDGET 8
 
 #ifdef CONFIG_NET_RX_BUSY_POLL
 
@@ -46,7 +47,7 @@  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, u16 budget);
 
 #else /* CONFIG_NET_RX_BUSY_POLL */
 static inline unsigned long net_busy_loop_on(void)
@@ -119,7 +120,8 @@  static inline void sk_busy_loop(struct sock *sk, int nonblock)
 
 	if (napi_id >= MIN_NAPI_ID) {
 		__sk_bias_busy_poll(sk, 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,
+			       sk->sk_busy_poll_budget ?: BUSY_POLL_BUDGET);
 	}
 #endif
 }
diff --git a/include/net/sock.h b/include/net/sock.h
index cf71834fb601..3caf53b6bd71 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -481,6 +481,7 @@  struct sock {
 	kuid_t			sk_uid;
 #ifdef CONFIG_NET_RX_BUSY_POLL
 	u8			sk_bias_busy_poll;
+	u16			sk_busy_poll_budget;
 #endif
 	struct pid		*sk_peer_pid;
 	const struct cred	*sk_peer_cred;
diff --git a/include/uapi/asm-generic/socket.h b/include/uapi/asm-generic/socket.h
index 8a2b37ccd9d5..9dc1f35fe77f 100644
--- a/include/uapi/asm-generic/socket.h
+++ b/include/uapi/asm-generic/socket.h
@@ -120,6 +120,7 @@ 
 #define SO_DETACH_REUSEPORT_BPF 68
 
 #define SO_BIAS_BUSY_POLL	69
+#define SO_BUSY_POLL_BUDGET	70
 
 #if !defined(__KERNEL__)
 
diff --git a/net/core/dev.c b/net/core/dev.c
index a29e4c4a35f6..b34520acaa7f 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -6496,9 +6496,7 @@  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, u16 budget)
 {
 	int rc;
 
@@ -6530,14 +6528,14 @@  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);
+	rc = napi->poll(napi, budget);
 	/* We can't gro_normal_list() here, because napi->poll() might have
 	 * rearmed the napi (napi_complete_done()) in which case it could
 	 * already be running on another CPU.
 	 */
-	trace_napi_poll(napi, rc, BUSY_POLL_BUDGET);
+	trace_napi_poll(napi, rc, budget);
 	netpoll_poll_unlock(have_poll_lock);
-	if (rc == BUSY_POLL_BUDGET) {
+	if (rc == budget) {
 		/* As the whole budget was spent, we still own the napi so can
 		 * safely handle the rx_list.
 		 */
@@ -6549,7 +6547,7 @@  static void busy_poll_stop(struct napi_struct *napi, void *have_poll_lock)
 
 void napi_busy_loop(unsigned int napi_id,
 		    bool (*loop_end)(void *, unsigned long),
-		    void *loop_end_arg)
+		    void *loop_end_arg, u16 budget)
 {
 	unsigned long start_time = loop_end ? busy_loop_current_time() : 0;
 	int (*napi_poll)(struct napi_struct *napi, int budget);
@@ -6591,8 +6589,8 @@  void napi_busy_loop(unsigned int napi_id,
 					      HRTIMER_MODE_REL_PINNED);
 			}
 		}
-		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);
 		gro_normal_list(napi);
 count:
 		if (work > 0)
@@ -6605,7 +6603,7 @@  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();
@@ -6616,7 +6614,7 @@  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();
diff --git a/net/core/sock.c b/net/core/sock.c
index 686eb5549b79..799125de4add 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1165,6 +1165,16 @@  int sock_setsockopt(struct socket *sock, int level, int optname,
 		else
 			sk->sk_bias_busy_poll = valbool;
 		break;
+	case SO_BUSY_POLL_BUDGET:
+		if ((val > sk->sk_busy_poll_budget) && !capable(CAP_NET_ADMIN))
+			ret = -EPERM;
+		else {
+			if (val < 0)
+				ret = -EINVAL;
+			else
+				sk->sk_busy_poll_budget = val;
+		}
+		break;
 #endif
 
 	case SO_MAX_PACING_RATE: