From 6d11cfdba52af08b889fd6d3ee4212930493eb38 Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Wed, 22 May 2013 22:42:36 +0000 Subject: netfilter: don't panic on error while walking through the init path Don't panic if we hit an error while adding the nf_log or pernet netfilter support, just bail out. Signed-off-by: Pablo Neira Ayuso Acked-by: Gao feng --- net/socket.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'net/socket.c') diff --git a/net/socket.c b/net/socket.c index 6b94633ca61d..734194d36242 100644 --- a/net/socket.c +++ b/net/socket.c @@ -2612,7 +2612,9 @@ static int __init sock_init(void) */ #ifdef CONFIG_NETFILTER - netfilter_init(); + err = netfilter_init(); + if (err) + goto out; #endif #ifdef CONFIG_NETWORK_PHY_TIMESTAMPING -- cgit v1.2.3 From 060212928670593fb89243640bf05cf89560b023 Mon Sep 17 00:00:00 2001 From: Eliezer Tamir Date: Mon, 10 Jun 2013 11:39:50 +0300 Subject: net: add low latency socket poll Adds an ndo_ll_poll method and the code that supports it. This method can be used by low latency applications to busy-poll Ethernet device queues directly from the socket code. sysctl_net_ll_poll controls how many microseconds to poll. Default is zero (disabled). Individual protocol support will be added by subsequent patches. Signed-off-by: Alexander Duyck Signed-off-by: Jesse Brandeburg Signed-off-by: Eliezer Tamir Acked-by: Eric Dumazet Tested-by: Willem de Bruijn Signed-off-by: David S. Miller --- Documentation/sysctl/net.txt | 7 ++ include/linux/netdevice.h | 3 + include/linux/skbuff.h | 8 ++- include/net/ll_poll.h | 148 +++++++++++++++++++++++++++++++++++++++++++ include/net/sock.h | 4 ++ include/uapi/linux/snmp.h | 1 + net/Kconfig | 12 ++++ net/core/skbuff.c | 4 ++ net/core/sock.c | 6 ++ net/core/sysctl_net_core.c | 10 +++ net/ipv4/proc.c | 1 + net/socket.c | 6 ++ 12 files changed, 208 insertions(+), 2 deletions(-) create mode 100644 include/net/ll_poll.h (limited to 'net/socket.c') diff --git a/Documentation/sysctl/net.txt b/Documentation/sysctl/net.txt index c1f8640c2fc8..85ab72dcdc3c 100644 --- a/Documentation/sysctl/net.txt +++ b/Documentation/sysctl/net.txt @@ -50,6 +50,13 @@ The maximum number of packets that kernel can handle on a NAPI interrupt, it's a Per-CPU variable. Default: 64 +low_latency_poll +---------------- +Low latency busy poll timeout. (needs CONFIG_NET_LL_RX_POLL) +Approximate time in us to spin waiting for packets on the device queue. +Recommended value is 50. May increase power usage. +Default: 0 (off) + rmem_default ------------ diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 39bbd462d68e..2ecb96d9a1e5 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -971,6 +971,9 @@ struct net_device_ops { struct netpoll_info *info, gfp_t gfp); void (*ndo_netpoll_cleanup)(struct net_device *dev); +#endif +#ifdef CONFIG_NET_LL_RX_POLL + int (*ndo_ll_poll)(struct napi_struct *dev); #endif int (*ndo_set_vf_mac)(struct net_device *dev, int queue, u8 *mac); diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 9995834d2cb6..400d82ae2b03 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -386,6 +386,7 @@ typedef unsigned char *sk_buff_data_t; * @no_fcs: Request NIC to treat last 4 bytes as Ethernet FCS * @dma_cookie: a cookie to one of several possible DMA operations * done by skb DMA functions + * @napi_id: id of the NAPI struct this skb came from * @secmark: security marking * @mark: Generic packet mark * @dropcount: total number of sk_receive_queue overflows @@ -500,8 +501,11 @@ struct sk_buff { /* 7/9 bit hole (depending on ndisc_nodetype presence) */ kmemcheck_bitfield_end(flags2); -#ifdef CONFIG_NET_DMA - dma_cookie_t dma_cookie; +#if defined CONFIG_NET_DMA || defined CONFIG_NET_LL_RX_POLL + union { + unsigned int napi_id; + dma_cookie_t dma_cookie; + }; #endif #ifdef CONFIG_NETWORK_SECMARK __u32 secmark; diff --git a/include/net/ll_poll.h b/include/net/ll_poll.h new file mode 100644 index 000000000000..bc262f88173f --- /dev/null +++ b/include/net/ll_poll.h @@ -0,0 +1,148 @@ +/* + * Low Latency Sockets + * Copyright(c) 2013 Intel Corporation. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License along with + * this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA. + * + * Author: Eliezer Tamir + * + * Contact Information: + * e1000-devel Mailing List + */ + +/* + * For now this depends on CONFIG_X86_TSC + */ + +#ifndef _LINUX_NET_LL_POLL_H +#define _LINUX_NET_LL_POLL_H + +#include +#include + +#ifdef CONFIG_NET_LL_RX_POLL + +struct napi_struct; +extern unsigned long sysctl_net_ll_poll __read_mostly; + +/* return values from ndo_ll_poll */ +#define LL_FLUSH_FAILED -1 +#define LL_FLUSH_BUSY -2 + +/* we don't mind a ~2.5% imprecision */ +#define TSC_MHZ (tsc_khz >> 10) + +static inline cycles_t ll_end_time(void) +{ + return TSC_MHZ * ACCESS_ONCE(sysctl_net_ll_poll) + get_cycles(); +} + +static inline bool sk_valid_ll(struct sock *sk) +{ + return sysctl_net_ll_poll && sk->sk_napi_id && + !need_resched() && !signal_pending(current); +} + +static inline bool can_poll_ll(cycles_t end_time) +{ + return !time_after((unsigned long)get_cycles(), + (unsigned long)end_time); +} + +static inline bool sk_poll_ll(struct sock *sk, int nonblock) +{ + cycles_t end_time = ll_end_time(); + const struct net_device_ops *ops; + struct napi_struct *napi; + int rc = false; + + /* + * rcu read lock for napi hash + * bh so we don't race with net_rx_action + */ + rcu_read_lock_bh(); + + napi = napi_by_id(sk->sk_napi_id); + if (!napi) + goto out; + + ops = napi->dev->netdev_ops; + if (!ops->ndo_ll_poll) + goto out; + + do { + + rc = ops->ndo_ll_poll(napi); + + if (rc == LL_FLUSH_FAILED) + break; /* permanent failure */ + + if (rc > 0) + /* local bh are disabled so it is ok to use _BH */ + NET_ADD_STATS_BH(sock_net(sk), + LINUX_MIB_LOWLATENCYRXPACKETS, rc); + + } while (skb_queue_empty(&sk->sk_receive_queue) + && can_poll_ll(end_time) && !nonblock); + + rc = !skb_queue_empty(&sk->sk_receive_queue); +out: + rcu_read_unlock_bh(); + return rc; +} + +/* used in the NIC receive handler to mark the skb */ +static inline void skb_mark_ll(struct sk_buff *skb, struct napi_struct *napi) +{ + skb->napi_id = napi->napi_id; +} + +/* used in the protocol hanlder to propagate the napi_id to the socket */ +static inline void sk_mark_ll(struct sock *sk, struct sk_buff *skb) +{ + sk->sk_napi_id = skb->napi_id; +} + +#else /* CONFIG_NET_LL_RX_POLL */ + +static inline cycles_t ll_end_time(void) +{ + return 0; +} + +static inline bool sk_valid_ll(struct sock *sk) +{ + return false; +} + +static inline bool sk_poll_ll(struct sock *sk, int nonblock) +{ + return false; +} + +static inline void skb_mark_ll(struct sk_buff *skb, struct napi_struct *napi) +{ +} + +static inline void sk_mark_ll(struct sock *sk, struct sk_buff *skb) +{ +} + +static inline bool can_poll_ll(cycles_t end_time) +{ + return false; +} + +#endif /* CONFIG_NET_LL_RX_POLL */ +#endif /* _LINUX_NET_LL_POLL_H */ diff --git a/include/net/sock.h b/include/net/sock.h index 66772cf8c3c5..ac8e1818380c 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -229,6 +229,7 @@ struct cg_proto; * @sk_omem_alloc: "o" is "option" or "other" * @sk_wmem_queued: persistent queue size * @sk_forward_alloc: space allocated forward + * @sk_napi_id: id of the last napi context to receive data for sk * @sk_allocation: allocation mode * @sk_sndbuf: size of send buffer in bytes * @sk_flags: %SO_LINGER (l_onoff), %SO_BROADCAST, %SO_KEEPALIVE, @@ -324,6 +325,9 @@ struct sock { int sk_forward_alloc; #ifdef CONFIG_RPS __u32 sk_rxhash; +#endif +#ifdef CONFIG_NET_LL_RX_POLL + unsigned int sk_napi_id; #endif atomic_t sk_drops; int sk_rcvbuf; diff --git a/include/uapi/linux/snmp.h b/include/uapi/linux/snmp.h index df2e8b4f9c03..26cbf76f8058 100644 --- a/include/uapi/linux/snmp.h +++ b/include/uapi/linux/snmp.h @@ -253,6 +253,7 @@ enum LINUX_MIB_TCPFASTOPENLISTENOVERFLOW, /* TCPFastOpenListenOverflow */ LINUX_MIB_TCPFASTOPENCOOKIEREQD, /* TCPFastOpenCookieReqd */ LINUX_MIB_TCPSPURIOUS_RTX_HOSTQUEUES, /* TCPSpuriousRtxHostQueues */ + LINUX_MIB_LOWLATENCYRXPACKETS, /* LowLatencyRxPackets */ __LINUX_MIB_MAX }; diff --git a/net/Kconfig b/net/Kconfig index 523e43e6da1b..d6a9ce6e1800 100644 --- a/net/Kconfig +++ b/net/Kconfig @@ -243,6 +243,18 @@ config NETPRIO_CGROUP Cgroup subsystem for use in assigning processes to network priorities on a per-interface basis +config NET_LL_RX_POLL + bool "Low Latency Receive Poll" + depends on X86_TSC + default n + ---help--- + Support Low Latency Receive Queue Poll. + (For network card drivers which support this option.) + When waiting for data in read or poll call directly into the the device driver + to flush packets which may be pending on the device queues into the stack. + + If unsure, say N. + config BQL boolean depends on SYSFS diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 73f57a0e1523..4a4181e16c1a 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -733,6 +733,10 @@ static void __copy_skb_header(struct sk_buff *new, const struct sk_buff *old) new->vlan_tci = old->vlan_tci; skb_copy_secmark(new, old); + +#ifdef CONFIG_NET_LL_RX_POLL + new->napi_id = old->napi_id; +#endif } /* diff --git a/net/core/sock.c b/net/core/sock.c index 88868a9d21da..788c0da5eed1 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -139,6 +139,8 @@ #include #endif +#include + static DEFINE_MUTEX(proto_list_mutex); static LIST_HEAD(proto_list); @@ -2284,6 +2286,10 @@ void sock_init_data(struct socket *sock, struct sock *sk) sk->sk_stamp = ktime_set(-1L, 0); +#ifdef CONFIG_NET_LL_RX_POLL + sk->sk_napi_id = 0; +#endif + /* * Before updating sk_refcnt, we must commit prior changes to memory * (Documentation/RCU/rculist_nulls.txt for details) diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c index 741db5fc7806..4b48f39582b0 100644 --- a/net/core/sysctl_net_core.c +++ b/net/core/sysctl_net_core.c @@ -19,6 +19,7 @@ #include #include #include +#include static int one = 1; @@ -284,6 +285,15 @@ static struct ctl_table net_core_table[] = { .proc_handler = flow_limit_table_len_sysctl }, #endif /* CONFIG_NET_FLOW_LIMIT */ +#ifdef CONFIG_NET_LL_RX_POLL + { + .procname = "low_latency_poll", + .data = &sysctl_net_ll_poll, + .maxlen = sizeof(unsigned long), + .mode = 0644, + .proc_handler = proc_doulongvec_minmax + }, +#endif #endif /* CONFIG_NET */ { .procname = "netdev_budget", diff --git a/net/ipv4/proc.c b/net/ipv4/proc.c index 2a5bf86d2415..6577a1149a47 100644 --- a/net/ipv4/proc.c +++ b/net/ipv4/proc.c @@ -273,6 +273,7 @@ static const struct snmp_mib snmp4_net_list[] = { SNMP_MIB_ITEM("TCPFastOpenListenOverflow", LINUX_MIB_TCPFASTOPENLISTENOVERFLOW), SNMP_MIB_ITEM("TCPFastOpenCookieReqd", LINUX_MIB_TCPFASTOPENCOOKIEREQD), SNMP_MIB_ITEM("TCPSpuriousRtxHostQueues", LINUX_MIB_TCPSPURIOUS_RTX_HOSTQUEUES), + SNMP_MIB_ITEM("LowLatencyRxPackets", LINUX_MIB_LOWLATENCYRXPACKETS), SNMP_MIB_SENTINEL }; diff --git a/net/socket.c b/net/socket.c index 3ebdcb805c51..21fd29f63ed2 100644 --- a/net/socket.c +++ b/net/socket.c @@ -104,6 +104,12 @@ #include #include #include +#include + +#ifdef CONFIG_NET_LL_RX_POLL +unsigned long sysctl_net_ll_poll __read_mostly; +EXPORT_SYMBOL_GPL(sysctl_net_ll_poll); +#endif static int sock_no_open(struct inode *irrelevant, struct file *dontcare); static ssize_t sock_aio_read(struct kiocb *iocb, const struct iovec *iov, -- cgit v1.2.3 From eb6db622825b2028df74f490b8c36887cf3c2f50 Mon Sep 17 00:00:00 2001 From: Eliezer Tamir Date: Fri, 14 Jun 2013 16:33:25 +0300 Subject: net: change sysctl_net_ll_poll into an unsigned int There is no reason for sysctl_net_ll_poll to be an unsigned long. Change it into an unsigned int. Fix the proc handler. Signed-off-by: Eliezer Tamir Signed-off-by: David S. Miller --- include/net/ll_poll.h | 5 +++-- net/core/sysctl_net_core.c | 4 ++-- net/socket.c | 2 +- 3 files changed, 6 insertions(+), 5 deletions(-) (limited to 'net/socket.c') diff --git a/include/net/ll_poll.h b/include/net/ll_poll.h index bc262f88173f..44e2f707cb9f 100644 --- a/include/net/ll_poll.h +++ b/include/net/ll_poll.h @@ -34,7 +34,7 @@ #ifdef CONFIG_NET_LL_RX_POLL struct napi_struct; -extern unsigned long sysctl_net_ll_poll __read_mostly; +extern unsigned int sysctl_net_ll_poll __read_mostly; /* return values from ndo_ll_poll */ #define LL_FLUSH_FAILED -1 @@ -45,7 +45,8 @@ extern unsigned long sysctl_net_ll_poll __read_mostly; static inline cycles_t ll_end_time(void) { - return TSC_MHZ * ACCESS_ONCE(sysctl_net_ll_poll) + get_cycles(); + return (cycles_t)TSC_MHZ * ACCESS_ONCE(sysctl_net_ll_poll) + + get_cycles(); } static inline bool sk_valid_ll(struct sock *sk) diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c index 78c746e016ae..62702c2053de 100644 --- a/net/core/sysctl_net_core.c +++ b/net/core/sysctl_net_core.c @@ -302,9 +302,9 @@ static struct ctl_table net_core_table[] = { { .procname = "low_latency_poll", .data = &sysctl_net_ll_poll, - .maxlen = sizeof(unsigned long), + .maxlen = sizeof(unsigned int), .mode = 0644, - .proc_handler = proc_doulongvec_minmax + .proc_handler = proc_dointvec }, #endif #endif /* CONFIG_NET */ diff --git a/net/socket.c b/net/socket.c index 21fd29f63ed2..caaffa14e87e 100644 --- a/net/socket.c +++ b/net/socket.c @@ -107,7 +107,7 @@ #include #ifdef CONFIG_NET_LL_RX_POLL -unsigned long sysctl_net_ll_poll __read_mostly; +unsigned int sysctl_net_ll_poll __read_mostly; EXPORT_SYMBOL_GPL(sysctl_net_ll_poll); #endif -- cgit v1.2.3 From dafcc4380deec21d160c31411f33c8813f67f517 Mon Sep 17 00:00:00 2001 From: Eliezer Tamir Date: Fri, 14 Jun 2013 16:33:57 +0300 Subject: net: add socket option for low latency polling adds a socket option for low latency polling. This allows overriding the global sysctl value with a per-socket one. Unexport sysctl_net_ll_poll since for now it's not needed in modules. Signed-off-by: Eliezer Tamir Signed-off-by: David S. Miller --- arch/alpha/include/uapi/asm/socket.h | 2 ++ arch/avr32/include/uapi/asm/socket.h | 2 ++ arch/cris/include/uapi/asm/socket.h | 2 ++ arch/frv/include/uapi/asm/socket.h | 2 ++ arch/h8300/include/uapi/asm/socket.h | 2 ++ arch/ia64/include/uapi/asm/socket.h | 2 ++ arch/m32r/include/uapi/asm/socket.h | 2 ++ arch/mips/include/uapi/asm/socket.h | 2 ++ arch/mn10300/include/uapi/asm/socket.h | 2 ++ arch/parisc/include/uapi/asm/socket.h | 2 ++ arch/powerpc/include/uapi/asm/socket.h | 2 ++ arch/s390/include/uapi/asm/socket.h | 2 ++ arch/sparc/include/uapi/asm/socket.h | 2 ++ arch/xtensa/include/uapi/asm/socket.h | 2 ++ include/net/ll_poll.h | 12 ++++++------ include/net/sock.h | 2 ++ include/uapi/asm-generic/socket.h | 2 ++ net/core/sock.c | 20 ++++++++++++++++++++ net/socket.c | 1 - 19 files changed, 58 insertions(+), 7 deletions(-) (limited to 'net/socket.c') diff --git a/arch/alpha/include/uapi/asm/socket.h b/arch/alpha/include/uapi/asm/socket.h index eee6ea76bdaf..4885825e498d 100644 --- a/arch/alpha/include/uapi/asm/socket.h +++ b/arch/alpha/include/uapi/asm/socket.h @@ -81,4 +81,6 @@ #define SO_SELECT_ERR_QUEUE 45 +#define SO_LL 46 + #endif /* _UAPI_ASM_SOCKET_H */ diff --git a/arch/avr32/include/uapi/asm/socket.h b/arch/avr32/include/uapi/asm/socket.h index 37401f535126..79b61798ebf8 100644 --- a/arch/avr32/include/uapi/asm/socket.h +++ b/arch/avr32/include/uapi/asm/socket.h @@ -74,4 +74,6 @@ #define SO_SELECT_ERR_QUEUE 45 +#define SO_LL 46 + #endif /* __ASM_AVR32_SOCKET_H */ diff --git a/arch/cris/include/uapi/asm/socket.h b/arch/cris/include/uapi/asm/socket.h index ba409c9947bc..47b1ec55092d 100644 --- a/arch/cris/include/uapi/asm/socket.h +++ b/arch/cris/include/uapi/asm/socket.h @@ -76,6 +76,8 @@ #define SO_SELECT_ERR_QUEUE 45 +#define SO_LL 46 + #endif /* _ASM_SOCKET_H */ diff --git a/arch/frv/include/uapi/asm/socket.h b/arch/frv/include/uapi/asm/socket.h index 31dbb5d8e13d..dbc08520f22c 100644 --- a/arch/frv/include/uapi/asm/socket.h +++ b/arch/frv/include/uapi/asm/socket.h @@ -74,5 +74,7 @@ #define SO_SELECT_ERR_QUEUE 45 +#define SO_LL 46 + #endif /* _ASM_SOCKET_H */ diff --git a/arch/h8300/include/uapi/asm/socket.h b/arch/h8300/include/uapi/asm/socket.h index 5d1c6d0870e6..a38d38a6520b 100644 --- a/arch/h8300/include/uapi/asm/socket.h +++ b/arch/h8300/include/uapi/asm/socket.h @@ -74,4 +74,6 @@ #define SO_SELECT_ERR_QUEUE 45 +#define SO_LL 46 + #endif /* _ASM_SOCKET_H */ diff --git a/arch/ia64/include/uapi/asm/socket.h b/arch/ia64/include/uapi/asm/socket.h index 6b4329f18b29..d3358b760681 100644 --- a/arch/ia64/include/uapi/asm/socket.h +++ b/arch/ia64/include/uapi/asm/socket.h @@ -83,4 +83,6 @@ #define SO_SELECT_ERR_QUEUE 45 +#define SO_LL 46 + #endif /* _ASM_IA64_SOCKET_H */ diff --git a/arch/m32r/include/uapi/asm/socket.h b/arch/m32r/include/uapi/asm/socket.h index 2a3b59e0e171..44aaf4639a4a 100644 --- a/arch/m32r/include/uapi/asm/socket.h +++ b/arch/m32r/include/uapi/asm/socket.h @@ -74,4 +74,6 @@ #define SO_SELECT_ERR_QUEUE 45 +#define SO_LL 46 + #endif /* _ASM_M32R_SOCKET_H */ diff --git a/arch/mips/include/uapi/asm/socket.h b/arch/mips/include/uapi/asm/socket.h index 3b211507be7f..6a07992ba6c6 100644 --- a/arch/mips/include/uapi/asm/socket.h +++ b/arch/mips/include/uapi/asm/socket.h @@ -92,4 +92,6 @@ #define SO_SELECT_ERR_QUEUE 45 +#define SO_LL 46 + #endif /* _UAPI_ASM_SOCKET_H */ diff --git a/arch/mn10300/include/uapi/asm/socket.h b/arch/mn10300/include/uapi/asm/socket.h index b4ce844c9391..db80fd3e398b 100644 --- a/arch/mn10300/include/uapi/asm/socket.h +++ b/arch/mn10300/include/uapi/asm/socket.h @@ -74,4 +74,6 @@ #define SO_SELECT_ERR_QUEUE 45 +#define SO_LL 46 + #endif /* _ASM_SOCKET_H */ diff --git a/arch/parisc/include/uapi/asm/socket.h b/arch/parisc/include/uapi/asm/socket.h index 70c512a386f7..f866fff9a004 100644 --- a/arch/parisc/include/uapi/asm/socket.h +++ b/arch/parisc/include/uapi/asm/socket.h @@ -73,6 +73,8 @@ #define SO_SELECT_ERR_QUEUE 0x4026 +#define SO_LL 0x4027 + /* O_NONBLOCK clashes with the bits used for socket types. Therefore we * have to define SOCK_NONBLOCK to a different value here. */ diff --git a/arch/powerpc/include/uapi/asm/socket.h b/arch/powerpc/include/uapi/asm/socket.h index a36daf3c6f9a..405fb09bda94 100644 --- a/arch/powerpc/include/uapi/asm/socket.h +++ b/arch/powerpc/include/uapi/asm/socket.h @@ -81,4 +81,6 @@ #define SO_SELECT_ERR_QUEUE 45 +#define SO_LL 46 + #endif /* _ASM_POWERPC_SOCKET_H */ diff --git a/arch/s390/include/uapi/asm/socket.h b/arch/s390/include/uapi/asm/socket.h index 2dacb306835c..0c5105fbaaf3 100644 --- a/arch/s390/include/uapi/asm/socket.h +++ b/arch/s390/include/uapi/asm/socket.h @@ -80,4 +80,6 @@ #define SO_SELECT_ERR_QUEUE 45 +#define SO_LL 46 + #endif /* _ASM_SOCKET_H */ diff --git a/arch/sparc/include/uapi/asm/socket.h b/arch/sparc/include/uapi/asm/socket.h index 89f49b68a21c..b46c3fa0b265 100644 --- a/arch/sparc/include/uapi/asm/socket.h +++ b/arch/sparc/include/uapi/asm/socket.h @@ -70,6 +70,8 @@ #define SO_SELECT_ERR_QUEUE 0x0029 +#define SO_LL 0x0030 + /* Security levels - as per NRL IPv6 - don't actually do anything */ #define SO_SECURITY_AUTHENTICATION 0x5001 #define SO_SECURITY_ENCRYPTION_TRANSPORT 0x5002 diff --git a/arch/xtensa/include/uapi/asm/socket.h b/arch/xtensa/include/uapi/asm/socket.h index a8f44f50e651..b21ace4fc9ba 100644 --- a/arch/xtensa/include/uapi/asm/socket.h +++ b/arch/xtensa/include/uapi/asm/socket.h @@ -85,4 +85,6 @@ #define SO_SELECT_ERR_QUEUE 45 +#define SO_LL 46 + #endif /* _XTENSA_SOCKET_H */ diff --git a/include/net/ll_poll.h b/include/net/ll_poll.h index 6930cbd943e2..fcc7c365cee5 100644 --- a/include/net/ll_poll.h +++ b/include/net/ll_poll.h @@ -39,12 +39,12 @@ extern unsigned int sysctl_net_ll_poll __read_mostly; /* we can use sched_clock() because we don't care much about precision * we only care that the average is bounded */ -static inline u64 ll_end_time(void) +static inline u64 ll_end_time(struct sock *sk) { - u64 end_time = ACCESS_ONCE(sysctl_net_ll_poll); + u64 end_time = ACCESS_ONCE(sk->sk_ll_usec); /* we don't mind a ~2.5% imprecision - * sysctl_net_ll_poll is a u_int so this can't overflow + * sk->sk_ll_usec is a u_int so this can't overflow */ end_time = (end_time << 10) + sched_clock(); @@ -53,7 +53,7 @@ static inline u64 ll_end_time(void) static inline bool sk_valid_ll(struct sock *sk) { - return sysctl_net_ll_poll && sk->sk_napi_id && + return sk->sk_ll_usec && sk->sk_napi_id && !need_resched() && !signal_pending(current); } @@ -65,7 +65,7 @@ static inline bool can_poll_ll(u64 end_time) static inline bool sk_poll_ll(struct sock *sk, int nonblock) { const struct net_device_ops *ops; - u64 end_time = ll_end_time(); + u64 end_time = ll_end_time(sk); struct napi_struct *napi; int rc = false; @@ -118,7 +118,7 @@ static inline void sk_mark_ll(struct sock *sk, struct sk_buff *skb) #else /* CONFIG_NET_LL_RX_POLL */ -static inline u64 ll_end_time(void) +static inline u64 ll_end_time(struct sock *sk) { return 0; } diff --git a/include/net/sock.h b/include/net/sock.h index ac8e1818380c..21db792bffa5 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -230,6 +230,7 @@ struct cg_proto; * @sk_wmem_queued: persistent queue size * @sk_forward_alloc: space allocated forward * @sk_napi_id: id of the last napi context to receive data for sk + * @sk_ll_usec: usecs to busypoll when there is no data * @sk_allocation: allocation mode * @sk_sndbuf: size of send buffer in bytes * @sk_flags: %SO_LINGER (l_onoff), %SO_BROADCAST, %SO_KEEPALIVE, @@ -328,6 +329,7 @@ struct sock { #endif #ifdef CONFIG_NET_LL_RX_POLL unsigned int sk_napi_id; + unsigned int sk_ll_usec; #endif atomic_t sk_drops; int sk_rcvbuf; diff --git a/include/uapi/asm-generic/socket.h b/include/uapi/asm-generic/socket.h index c5d2e3a1cf68..ca3a20d772ac 100644 --- a/include/uapi/asm-generic/socket.h +++ b/include/uapi/asm-generic/socket.h @@ -76,4 +76,6 @@ #define SO_SELECT_ERR_QUEUE 45 +#define SO_LL 46 + #endif /* __ASM_GENERIC_SOCKET_H */ diff --git a/net/core/sock.c b/net/core/sock.c index 788c0da5eed1..1e744b12fda3 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -913,6 +913,19 @@ set_rcvbuf: sock_valbool_flag(sk, SOCK_SELECT_ERR_QUEUE, valbool); break; +#ifdef CONFIG_NET_LL_RX_POLL + case SO_LL: + /* allow unprivileged users to decrease the value */ + if ((val > sk->sk_ll_usec) && !capable(CAP_NET_ADMIN)) + ret = -EPERM; + else { + if (val < 0) + ret = -EINVAL; + else + sk->sk_ll_usec = val; + } + break; +#endif default: ret = -ENOPROTOOPT; break; @@ -1170,6 +1183,12 @@ int sock_getsockopt(struct socket *sock, int level, int optname, v.val = sock_flag(sk, SOCK_SELECT_ERR_QUEUE); break; +#ifdef CONFIG_NET_LL_RX_POLL + case SO_LL: + v.val = sk->sk_ll_usec; + break; +#endif + default: return -ENOPROTOOPT; } @@ -2288,6 +2307,7 @@ void sock_init_data(struct socket *sock, struct sock *sk) #ifdef CONFIG_NET_LL_RX_POLL sk->sk_napi_id = 0; + sk->sk_ll_usec = sysctl_net_ll_poll; #endif /* diff --git a/net/socket.c b/net/socket.c index caaffa14e87e..3eec3f76b49c 100644 --- a/net/socket.c +++ b/net/socket.c @@ -108,7 +108,6 @@ #ifdef CONFIG_NET_LL_RX_POLL unsigned int sysctl_net_ll_poll __read_mostly; -EXPORT_SYMBOL_GPL(sysctl_net_ll_poll); #endif static int sock_no_open(struct inode *irrelevant, struct file *dontcare); -- cgit v1.2.3 From 2d48d67fa8cd129ea85ea02d91b4a793286866f8 Mon Sep 17 00:00:00 2001 From: Eliezer Tamir Date: Mon, 24 Jun 2013 10:28:03 +0300 Subject: net: poll/select low latency socket support select/poll busy-poll support. Split sysctl value into two separate ones, one for read and one for poll. updated Documentation/sysctl/net.txt Add a new poll flag POLL_LL. When this flag is set, sock_poll will call sk_poll_ll if possible. sock_poll sets this flag in its return value to indicate to select/poll when a socket that can busy poll is found. When poll/select have nothing to report, call the low-level sock_poll again until we are out of time or we find something. Once the system call finds something, it stops setting POLL_LL, so it can return the result to the user ASAP. Signed-off-by: Eliezer Tamir Signed-off-by: David S. Miller --- Documentation/sysctl/net.txt | 18 ++++++++++++++++-- fs/select.c | 34 +++++++++++++++++++++++++++++----- include/net/ll_poll.h | 35 ++++++++++++++++++++++------------- include/uapi/asm-generic/poll.h | 2 ++ net/core/sock.c | 2 +- net/core/sysctl_net_core.c | 8 ++++++++ net/socket.c | 14 +++++++++++++- 7 files changed, 91 insertions(+), 22 deletions(-) (limited to 'net/socket.c') diff --git a/Documentation/sysctl/net.txt b/Documentation/sysctl/net.txt index 5369879eafe2..e658bbfb641f 100644 --- a/Documentation/sysctl/net.txt +++ b/Documentation/sysctl/net.txt @@ -50,13 +50,27 @@ The maximum number of packets that kernel can handle on a NAPI interrupt, it's a Per-CPU variable. Default: 64 -low_latency_poll +low_latency_read ---------------- -Low latency busy poll timeout. (needs CONFIG_NET_LL_RX_POLL) +Low latency busy poll timeout for socket reads. (needs CONFIG_NET_LL_RX_POLL) Approximate time in us to spin waiting for packets on the device queue. +This sets the default value of the SO_LL socket option. +Can be set or overridden per socket by setting socket option SO_LL. Recommended value is 50. May increase power usage. Default: 0 (off) +low_latency_poll +---------------- +Low latency busy poll timeout for poll and select. (needs CONFIG_NET_LL_RX_POLL) +Approximate time in us to spin waiting for packets on the device queue. +Recommended value depends on the number of sockets you poll on. +For several sockets 50, for several hundreds 100. +For more than that you probably want to use epoll. +Note that only sockets with SO_LL set will be busy polled, so you want to either +selectively set SO_LL on those sockets or set sysctl.net.low_latency_read globally. +May increase power usage. +Default: 0 (off) + rmem_default ------------ diff --git a/fs/select.c b/fs/select.c index 8c1c96c27062..79b876eb91da 100644 --- a/fs/select.c +++ b/fs/select.c @@ -27,6 +27,7 @@ #include #include #include +#include #include @@ -384,9 +385,10 @@ get_max: #define POLLEX_SET (POLLPRI) static inline void wait_key_set(poll_table *wait, unsigned long in, - unsigned long out, unsigned long bit) + unsigned long out, unsigned long bit, + unsigned int ll_flag) { - wait->_key = POLLEX_SET; + wait->_key = POLLEX_SET | ll_flag; if (in & bit) wait->_key |= POLLIN_SET; if (out & bit) @@ -400,6 +402,8 @@ int do_select(int n, fd_set_bits *fds, struct timespec *end_time) poll_table *wait; int retval, i, timed_out = 0; unsigned long slack = 0; + unsigned int ll_flag = POLL_LL; + u64 ll_time = ll_end_time(); rcu_read_lock(); retval = max_select_fd(n, fds); @@ -422,6 +426,7 @@ int do_select(int n, fd_set_bits *fds, struct timespec *end_time) retval = 0; for (;;) { unsigned long *rinp, *routp, *rexp, *inp, *outp, *exp; + bool can_ll = false; inp = fds->in; outp = fds->out; exp = fds->ex; rinp = fds->res_in; routp = fds->res_out; rexp = fds->res_ex; @@ -449,7 +454,8 @@ int do_select(int n, fd_set_bits *fds, struct timespec *end_time) f_op = f.file->f_op; mask = DEFAULT_POLLMASK; if (f_op && f_op->poll) { - wait_key_set(wait, in, out, bit); + wait_key_set(wait, in, out, + bit, ll_flag); mask = (*f_op->poll)(f.file, wait); } fdput(f); @@ -468,6 +474,11 @@ int do_select(int n, fd_set_bits *fds, struct timespec *end_time) retval++; wait->_qproc = NULL; } + if (mask & POLL_LL) + can_ll = true; + /* got something, stop busy polling */ + if (retval) + ll_flag = 0; } } if (res_in) @@ -486,6 +497,9 @@ int do_select(int n, fd_set_bits *fds, struct timespec *end_time) break; } + if (can_ll && can_poll_ll(ll_time)) + continue; + /* * If this is the first loop and we have a timeout * given, then we convert to ktime_t and set the to @@ -717,7 +731,8 @@ struct poll_list { * pwait poll_table will be used by the fd-provided poll handler for waiting, * if pwait->_qproc is non-NULL. */ -static inline unsigned int do_pollfd(struct pollfd *pollfd, poll_table *pwait) +static inline unsigned int do_pollfd(struct pollfd *pollfd, poll_table *pwait, + bool *can_ll, unsigned int ll_flag) { unsigned int mask; int fd; @@ -731,7 +746,10 @@ static inline unsigned int do_pollfd(struct pollfd *pollfd, poll_table *pwait) mask = DEFAULT_POLLMASK; if (f.file->f_op && f.file->f_op->poll) { pwait->_key = pollfd->events|POLLERR|POLLHUP; + pwait->_key |= ll_flag; mask = f.file->f_op->poll(f.file, pwait); + if (mask & POLL_LL) + *can_ll = true; } /* Mask out unneeded events. */ mask &= pollfd->events | POLLERR | POLLHUP; @@ -750,6 +768,8 @@ static int do_poll(unsigned int nfds, struct poll_list *list, ktime_t expire, *to = NULL; int timed_out = 0, count = 0; unsigned long slack = 0; + unsigned int ll_flag = POLL_LL; + u64 ll_time = ll_end_time(); /* Optimise the no-wait case */ if (end_time && !end_time->tv_sec && !end_time->tv_nsec) { @@ -762,6 +782,7 @@ static int do_poll(unsigned int nfds, struct poll_list *list, for (;;) { struct poll_list *walk; + bool can_ll = false; for (walk = list; walk != NULL; walk = walk->next) { struct pollfd * pfd, * pfd_end; @@ -776,9 +797,10 @@ static int do_poll(unsigned int nfds, struct poll_list *list, * this. They'll get immediately deregistered * when we break out and return. */ - if (do_pollfd(pfd, pt)) { + if (do_pollfd(pfd, pt, &can_ll, ll_flag)) { count++; pt->_qproc = NULL; + ll_flag = 0; } } } @@ -795,6 +817,8 @@ static int do_poll(unsigned int nfds, struct poll_list *list, if (count || timed_out) break; + if (can_ll && can_poll_ll(ll_time)) + continue; /* * If this is the first loop and we have a timeout * given, then we convert to ktime_t and set the to diff --git a/include/net/ll_poll.h b/include/net/ll_poll.h index fcc7c365cee5..5bf2b3a6129e 100644 --- a/include/net/ll_poll.h +++ b/include/net/ll_poll.h @@ -30,6 +30,7 @@ #ifdef CONFIG_NET_LL_RX_POLL struct napi_struct; +extern unsigned int sysctl_net_ll_read __read_mostly; extern unsigned int sysctl_net_ll_poll __read_mostly; /* return values from ndo_ll_poll */ @@ -38,17 +39,18 @@ extern unsigned int sysctl_net_ll_poll __read_mostly; /* we can use sched_clock() because we don't care much about precision * we only care that the average is bounded + * we don't mind a ~2.5% imprecision so <<10 instead of *1000 + * sk->sk_ll_usec is a u_int so this can't overflow */ -static inline u64 ll_end_time(struct sock *sk) +static inline u64 ll_sk_end_time(struct sock *sk) { - u64 end_time = ACCESS_ONCE(sk->sk_ll_usec); - - /* we don't mind a ~2.5% imprecision - * sk->sk_ll_usec is a u_int so this can't overflow - */ - end_time = (end_time << 10) + sched_clock(); + return ((u64)ACCESS_ONCE(sk->sk_ll_usec) << 10) + sched_clock(); +} - return end_time; +/* in poll/select we use the global sysctl_net_ll_poll value */ +static inline u64 ll_end_time(void) +{ + return ((u64)ACCESS_ONCE(sysctl_net_ll_poll) << 10) + sched_clock(); } static inline bool sk_valid_ll(struct sock *sk) @@ -62,10 +64,13 @@ static inline bool can_poll_ll(u64 end_time) return !time_after64(sched_clock(), end_time); } +/* when used in sock_poll() nonblock is known at compile time to be true + * so the loop and end_time will be optimized out + */ static inline bool sk_poll_ll(struct sock *sk, int nonblock) { + u64 end_time = nonblock ? 0 : ll_sk_end_time(sk); const struct net_device_ops *ops; - u64 end_time = ll_end_time(sk); struct napi_struct *napi; int rc = false; @@ -84,7 +89,6 @@ static inline bool sk_poll_ll(struct sock *sk, int nonblock) goto out; do { - rc = ops->ndo_ll_poll(napi); if (rc == LL_FLUSH_FAILED) @@ -95,8 +99,8 @@ static inline bool sk_poll_ll(struct sock *sk, int nonblock) NET_ADD_STATS_BH(sock_net(sk), LINUX_MIB_LOWLATENCYRXPACKETS, rc); - } while (skb_queue_empty(&sk->sk_receive_queue) - && can_poll_ll(end_time) && !nonblock); + } while (!nonblock && skb_queue_empty(&sk->sk_receive_queue) && + can_poll_ll(end_time)); rc = !skb_queue_empty(&sk->sk_receive_queue); out: @@ -118,7 +122,12 @@ static inline void sk_mark_ll(struct sock *sk, struct sk_buff *skb) #else /* CONFIG_NET_LL_RX_POLL */ -static inline u64 ll_end_time(struct sock *sk) +static inline u64 sk_ll_end_time(struct sock *sk) +{ + return 0; +} + +static inline u64 ll_end_time(void) { return 0; } diff --git a/include/uapi/asm-generic/poll.h b/include/uapi/asm-generic/poll.h index 9ce7f44aebd2..4aee586979ca 100644 --- a/include/uapi/asm-generic/poll.h +++ b/include/uapi/asm-generic/poll.h @@ -30,6 +30,8 @@ #define POLLFREE 0x4000 /* currently only for epoll */ +#define POLL_LL 0x8000 + struct pollfd { int fd; short events; diff --git a/net/core/sock.c b/net/core/sock.c index 1e744b12fda3..b6c619f4d47b 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -2307,7 +2307,7 @@ void sock_init_data(struct socket *sock, struct sock *sk) #ifdef CONFIG_NET_LL_RX_POLL sk->sk_napi_id = 0; - sk->sk_ll_usec = sysctl_net_ll_poll; + sk->sk_ll_usec = sysctl_net_ll_read; #endif /* diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c index 62702c2053de..afc677eadd93 100644 --- a/net/core/sysctl_net_core.c +++ b/net/core/sysctl_net_core.c @@ -306,6 +306,14 @@ static struct ctl_table net_core_table[] = { .mode = 0644, .proc_handler = proc_dointvec }, + { + .procname = "low_latency_read", + .data = &sysctl_net_ll_read, + .maxlen = sizeof(unsigned int), + .mode = 0644, + .proc_handler = proc_dointvec + }, +# #endif #endif /* CONFIG_NET */ { diff --git a/net/socket.c b/net/socket.c index 3eec3f76b49c..4da14cbd49b6 100644 --- a/net/socket.c +++ b/net/socket.c @@ -107,6 +107,7 @@ #include #ifdef CONFIG_NET_LL_RX_POLL +unsigned int sysctl_net_ll_read __read_mostly; unsigned int sysctl_net_ll_poll __read_mostly; #endif @@ -1147,13 +1148,24 @@ EXPORT_SYMBOL(sock_create_lite); /* No kernel lock held - perfect */ static unsigned int sock_poll(struct file *file, poll_table *wait) { + unsigned int ll_flag = 0; struct socket *sock; /* * We can't return errors to poll, so it's either yes or no. */ sock = file->private_data; - return sock->ops->poll(file, sock, wait); + + if (sk_valid_ll(sock->sk)) { + /* this socket can poll_ll so tell the system call */ + ll_flag = POLL_LL; + + /* once, only if requested by syscall */ + if (wait && (wait->_key & POLL_LL)) + sk_poll_ll(sock->sk, 1); + } + + return ll_flag | sock->ops->poll(file, sock, wait); } static int sock_mmap(struct file *file, struct vm_area_struct *vma) -- cgit v1.2.3 From cbf55001b2ddb814329735641be5d29b08c82b08 Mon Sep 17 00:00:00 2001 From: Eliezer Tamir Date: Mon, 8 Jul 2013 16:20:34 +0300 Subject: net: rename low latency sockets functions to busy poll Rename functions in include/net/ll_poll.h to busy wait. Clarify documentation about expected power use increase. Rename POLL_LL to POLL_BUSY_LOOP. Add need_resched() testing to poll/select busy loops. Note, that in select and poll can_busy_poll is dynamic and is updated continuously to reflect the existence of supported sockets with valid queue information. Signed-off-by: Eliezer Tamir Signed-off-by: David S. Miller --- Documentation/sysctl/net.txt | 12 +++++---- fs/select.c | 60 +++++++++++++++++++++++++---------------- include/net/ll_poll.h | 46 ++++++++++++++++--------------- include/uapi/asm-generic/poll.h | 2 +- net/core/datagram.c | 3 ++- net/ipv4/tcp.c | 6 ++--- net/socket.c | 12 ++++----- 7 files changed, 80 insertions(+), 61 deletions(-) (limited to 'net/socket.c') diff --git a/Documentation/sysctl/net.txt b/Documentation/sysctl/net.txt index e658bbfb641f..7323b88e26be 100644 --- a/Documentation/sysctl/net.txt +++ b/Documentation/sysctl/net.txt @@ -53,22 +53,24 @@ Default: 64 low_latency_read ---------------- Low latency busy poll timeout for socket reads. (needs CONFIG_NET_LL_RX_POLL) -Approximate time in us to spin waiting for packets on the device queue. +Approximate time in us to busy loop waiting for packets on the device queue. This sets the default value of the SO_LL socket option. -Can be set or overridden per socket by setting socket option SO_LL. -Recommended value is 50. May increase power usage. +Can be set or overridden per socket by setting socket option SO_LL, which is +the preferred method of enabling. +If you need to enable the feature globally via sysctl, a value of 50 is recommended. +Will increase power usage. Default: 0 (off) low_latency_poll ---------------- Low latency busy poll timeout for poll and select. (needs CONFIG_NET_LL_RX_POLL) -Approximate time in us to spin waiting for packets on the device queue. +Approximate time in us to busy loop waiting for events. Recommended value depends on the number of sockets you poll on. For several sockets 50, for several hundreds 100. For more than that you probably want to use epoll. Note that only sockets with SO_LL set will be busy polled, so you want to either selectively set SO_LL on those sockets or set sysctl.net.low_latency_read globally. -May increase power usage. +Will increase power usage. Default: 0 (off) rmem_default diff --git a/fs/select.c b/fs/select.c index f28a58592725..25cac5faf6d6 100644 --- a/fs/select.c +++ b/fs/select.c @@ -402,9 +402,9 @@ int do_select(int n, fd_set_bits *fds, struct timespec *end_time) poll_table *wait; int retval, i, timed_out = 0; unsigned long slack = 0; - unsigned int ll_flag = ll_get_flag(); - u64 ll_start = ll_start_time(ll_flag); - u64 ll_time = ll_run_time(); + unsigned int busy_flag = net_busy_loop_on() ? POLL_BUSY_LOOP : 0; + u64 busy_start = busy_loop_start_time(busy_flag); + u64 busy_end = busy_loop_end_time(); rcu_read_lock(); retval = max_select_fd(n, fds); @@ -427,7 +427,7 @@ int do_select(int n, fd_set_bits *fds, struct timespec *end_time) retval = 0; for (;;) { unsigned long *rinp, *routp, *rexp, *inp, *outp, *exp; - bool can_ll = false; + bool can_busy_loop = false; inp = fds->in; outp = fds->out; exp = fds->ex; rinp = fds->res_in; routp = fds->res_out; rexp = fds->res_ex; @@ -456,7 +456,7 @@ int do_select(int n, fd_set_bits *fds, struct timespec *end_time) mask = DEFAULT_POLLMASK; if (f_op && f_op->poll) { wait_key_set(wait, in, out, - bit, ll_flag); + bit, busy_flag); mask = (*f_op->poll)(f.file, wait); } fdput(f); @@ -475,11 +475,18 @@ int do_select(int n, fd_set_bits *fds, struct timespec *end_time) retval++; wait->_qproc = NULL; } - if (mask & POLL_LL) - can_ll = true; /* got something, stop busy polling */ - if (retval) - ll_flag = 0; + if (retval) { + can_busy_loop = false; + busy_flag = 0; + + /* + * only remember a returned + * POLL_BUSY_LOOP if we asked for it + */ + } else if (busy_flag & mask) + can_busy_loop = true; + } } if (res_in) @@ -498,8 +505,9 @@ int do_select(int n, fd_set_bits *fds, struct timespec *end_time) break; } - /* only if on, have sockets with POLL_LL and not out of time */ - if (ll_flag && can_ll && can_poll_ll(ll_start, ll_time)) + /* only if found POLL_BUSY_LOOP sockets && not out of time */ + if (!need_resched() && can_busy_loop && + busy_loop_range(busy_start, busy_end)) continue; /* @@ -734,7 +742,8 @@ struct poll_list { * if pwait->_qproc is non-NULL. */ static inline unsigned int do_pollfd(struct pollfd *pollfd, poll_table *pwait, - bool *can_ll, unsigned int ll_flag) + bool *can_busy_poll, + unsigned int busy_flag) { unsigned int mask; int fd; @@ -748,10 +757,10 @@ static inline unsigned int do_pollfd(struct pollfd *pollfd, poll_table *pwait, mask = DEFAULT_POLLMASK; if (f.file->f_op && f.file->f_op->poll) { pwait->_key = pollfd->events|POLLERR|POLLHUP; - pwait->_key |= ll_flag; + pwait->_key |= busy_flag; mask = f.file->f_op->poll(f.file, pwait); - if (mask & POLL_LL) - *can_ll = true; + if (mask & busy_flag) + *can_busy_poll = true; } /* Mask out unneeded events. */ mask &= pollfd->events | POLLERR | POLLHUP; @@ -770,9 +779,10 @@ static int do_poll(unsigned int nfds, struct poll_list *list, ktime_t expire, *to = NULL; int timed_out = 0, count = 0; unsigned long slack = 0; - unsigned int ll_flag = ll_get_flag(); - u64 ll_start = ll_start_time(ll_flag); - u64 ll_time = ll_run_time(); + unsigned int busy_flag = net_busy_loop_on() ? POLL_BUSY_LOOP : 0; + u64 busy_start = busy_loop_start_time(busy_flag); + u64 busy_end = busy_loop_end_time(); + /* Optimise the no-wait case */ if (end_time && !end_time->tv_sec && !end_time->tv_nsec) { @@ -785,7 +795,7 @@ static int do_poll(unsigned int nfds, struct poll_list *list, for (;;) { struct poll_list *walk; - bool can_ll = false; + bool can_busy_loop = false; for (walk = list; walk != NULL; walk = walk->next) { struct pollfd * pfd, * pfd_end; @@ -800,10 +810,13 @@ static int do_poll(unsigned int nfds, struct poll_list *list, * this. They'll get immediately deregistered * when we break out and return. */ - if (do_pollfd(pfd, pt, &can_ll, ll_flag)) { + if (do_pollfd(pfd, pt, &can_busy_loop, + busy_flag)) { count++; pt->_qproc = NULL; - ll_flag = 0; + /* found something, stop busy polling */ + busy_flag = 0; + can_busy_loop = false; } } } @@ -820,8 +833,9 @@ static int do_poll(unsigned int nfds, struct poll_list *list, if (count || timed_out) break; - /* only if on, have sockets with POLL_LL and not out of time */ - if (ll_flag && can_ll && can_poll_ll(ll_start, ll_time)) + /* only if found POLL_BUSY_LOOP sockets && not out of time */ + if (!need_resched() && can_busy_loop && + busy_loop_range(busy_start, busy_end)) continue; /* diff --git a/include/net/ll_poll.h b/include/net/ll_poll.h index 0d620ba19bc5..f14dd88dafc8 100644 --- a/include/net/ll_poll.h +++ b/include/net/ll_poll.h @@ -37,9 +37,9 @@ extern unsigned int sysctl_net_ll_poll __read_mostly; #define LL_FLUSH_FAILED -1 #define LL_FLUSH_BUSY -2 -static inline unsigned int ll_get_flag(void) +static inline bool net_busy_loop_on(void) { - return sysctl_net_ll_poll ? POLL_LL : 0; + return sysctl_net_ll_poll; } /* a wrapper to make debug_smp_processor_id() happy @@ -47,7 +47,7 @@ static inline unsigned int ll_get_flag(void) * we only care that the average is bounded */ #ifdef CONFIG_DEBUG_PREEMPT -static inline u64 ll_sched_clock(void) +static inline u64 busy_loop_sched_clock(void) { u64 rc; @@ -58,7 +58,7 @@ static inline u64 ll_sched_clock(void) return rc; } #else /* CONFIG_DEBUG_PREEMPT */ -static inline u64 ll_sched_clock(void) +static inline u64 busy_loop_sched_clock(void) { return sched_clock(); } @@ -67,7 +67,7 @@ static inline u64 ll_sched_clock(void) /* we don't mind a ~2.5% imprecision so <<10 instead of *1000 * sk->sk_ll_usec is a u_int so this can't overflow */ -static inline u64 ll_sk_run_time(struct sock *sk) +static inline u64 sk_busy_loop_end_time(struct sock *sk) { return (u64)ACCESS_ONCE(sk->sk_ll_usec) << 10; } @@ -75,27 +75,29 @@ static inline u64 ll_sk_run_time(struct sock *sk) /* in poll/select we use the global sysctl_net_ll_poll value * only call sched_clock() if enabled */ -static inline u64 ll_run_time(void) +static inline u64 busy_loop_end_time(void) { return (u64)ACCESS_ONCE(sysctl_net_ll_poll) << 10; } -/* if flag is not set we don't need to know the time */ -static inline u64 ll_start_time(unsigned int flag) +/* if flag is not set we don't need to know the time + * so we want to avoid a potentially expensive sched_clock() + */ +static inline u64 busy_loop_start_time(unsigned int flag) { - return flag ? ll_sched_clock() : 0; + return flag ? busy_loop_sched_clock() : 0; } -static inline bool sk_valid_ll(struct sock *sk) +static inline bool sk_can_busy_loop(struct sock *sk) { return sk->sk_ll_usec && sk->sk_napi_id && !need_resched() && !signal_pending(current); } /* careful! time_in_range64 will evaluate now twice */ -static inline bool can_poll_ll(u64 start_time, u64 run_time) +static inline bool busy_loop_range(u64 start_time, u64 run_time) { - u64 now = ll_sched_clock(); + u64 now = busy_loop_sched_clock(); return time_in_range64(now, start_time, start_time + run_time); } @@ -103,10 +105,10 @@ static inline bool can_poll_ll(u64 start_time, u64 run_time) /* when used in sock_poll() nonblock is known at compile time to be true * so the loop and end_time will be optimized out */ -static inline bool sk_poll_ll(struct sock *sk, int nonblock) +static inline bool sk_busy_loop(struct sock *sk, int nonblock) { - u64 start_time = ll_start_time(!nonblock); - u64 run_time = ll_sk_run_time(sk); + u64 start_time = busy_loop_start_time(!nonblock); + u64 end_time = sk_busy_loop_end_time(sk); const struct net_device_ops *ops; struct napi_struct *napi; int rc = false; @@ -137,7 +139,7 @@ static inline bool sk_poll_ll(struct sock *sk, int nonblock) LINUX_MIB_LOWLATENCYRXPACKETS, rc); } while (!nonblock && skb_queue_empty(&sk->sk_receive_queue) && - can_poll_ll(start_time, run_time)); + busy_loop_range(start_time, end_time)); rc = !skb_queue_empty(&sk->sk_receive_queue); out: @@ -158,27 +160,27 @@ static inline void sk_mark_ll(struct sock *sk, struct sk_buff *skb) } #else /* CONFIG_NET_LL_RX_POLL */ -static inline unsigned long ll_get_flag(void) +static inline unsigned long net_busy_loop_on(void) { return 0; } -static inline u64 ll_start_time(unsigned int flag) +static inline u64 busy_loop_start_time(unsigned int flag) { return 0; } -static inline u64 ll_run_time(void) +static inline u64 busy_loop_end_time(void) { return 0; } -static inline bool sk_valid_ll(struct sock *sk) +static inline bool sk_can_busy_loop(struct sock *sk) { return false; } -static inline bool sk_poll_ll(struct sock *sk, int nonblock) +static inline bool sk_busy_poll(struct sock *sk, int nonblock) { return false; } @@ -191,7 +193,7 @@ static inline void sk_mark_ll(struct sock *sk, struct sk_buff *skb) { } -static inline bool can_poll_ll(u64 start_time, u64 run_time) +static inline bool busy_loop_range(u64 start_time, u64 run_time) { return false; } diff --git a/include/uapi/asm-generic/poll.h b/include/uapi/asm-generic/poll.h index 4aee586979ca..a9694982689f 100644 --- a/include/uapi/asm-generic/poll.h +++ b/include/uapi/asm-generic/poll.h @@ -30,7 +30,7 @@ #define POLLFREE 0x4000 /* currently only for epoll */ -#define POLL_LL 0x8000 +#define POLL_BUSY_LOOP 0x8000 struct pollfd { int fd; diff --git a/net/core/datagram.c b/net/core/datagram.c index 9cbaba98ce4c..6e9ab31e457e 100644 --- a/net/core/datagram.c +++ b/net/core/datagram.c @@ -208,7 +208,8 @@ struct sk_buff *__skb_recv_datagram(struct sock *sk, unsigned int flags, } spin_unlock_irqrestore(&queue->lock, cpu_flags); - if (sk_valid_ll(sk) && sk_poll_ll(sk, flags & MSG_DONTWAIT)) + if (sk_can_busy_loop(sk) && + sk_busy_loop(sk, flags & MSG_DONTWAIT)) continue; /* User doesn't want to wait */ diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 46ed9afd1f5e..15cbfa94bd8e 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -1554,9 +1554,9 @@ int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, struct sk_buff *skb; u32 urg_hole = 0; - if (sk_valid_ll(sk) && skb_queue_empty(&sk->sk_receive_queue) - && (sk->sk_state == TCP_ESTABLISHED)) - sk_poll_ll(sk, nonblock); + if (sk_can_busy_loop(sk) && skb_queue_empty(&sk->sk_receive_queue) && + (sk->sk_state == TCP_ESTABLISHED)) + sk_busy_loop(sk, nonblock); lock_sock(sk); diff --git a/net/socket.c b/net/socket.c index 4da14cbd49b6..45afa648364a 100644 --- a/net/socket.c +++ b/net/socket.c @@ -1148,7 +1148,7 @@ EXPORT_SYMBOL(sock_create_lite); /* No kernel lock held - perfect */ static unsigned int sock_poll(struct file *file, poll_table *wait) { - unsigned int ll_flag = 0; + unsigned int busy_flag = 0; struct socket *sock; /* @@ -1156,16 +1156,16 @@ static unsigned int sock_poll(struct file *file, poll_table *wait) */ sock = file->private_data; - if (sk_valid_ll(sock->sk)) { + if (sk_can_busy_loop(sock->sk)) { /* this socket can poll_ll so tell the system call */ - ll_flag = POLL_LL; + busy_flag = POLL_BUSY_LOOP; /* once, only if requested by syscall */ - if (wait && (wait->_key & POLL_LL)) - sk_poll_ll(sock->sk, 1); + if (wait && (wait->_key & POLL_BUSY_LOOP)) + sk_busy_loop(sock->sk, 1); } - return ll_flag | sock->ops->poll(file, sock, wait); + return busy_flag | sock->ops->poll(file, sock, wait); } static int sock_mmap(struct file *file, struct vm_area_struct *vma) -- cgit v1.2.3