locking: Add lock contention tracepoints - linux-dev - Linux kernel development work

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author	Namhyung Kim <namhyung@kernel.org>	2022-03-22 11:57:08 -0700
committer	Peter Zijlstra <peterz@infradead.org>	2022-04-05 10:24:35 +0200
commit	16edd9b511a13e7760ed4b92ba4e39bacda5c86f (patch)
tree	00f84f1cf80f93a9ff061d3a40cab7cfeaa03d9d /kernel
parent	locking/rwsem: Always try to wake waiters in out_nolock path (diff)

locking: Add lock contention tracepoints

This adds two new lock contention tracepoints like below: * lock:contention_begin * lock:contention_end The lock:contention_begin takes a flags argument to classify locks. I found it useful to identify what kind of locks it's tracing like if it's spinning or sleeping, reader-writer lock, real-time, and per-cpu. Move tracepoint definitions into mutex.c so that we can use them without lockdep. Signed-off-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Link: https://lkml.kernel.org/r/20220322185709.141236-2-namhyung@kernel.org

Diffstat (limited to 'kernel')

-rw-r--r--

kernel/locking/lockdep.c

-rw-r--r--

kernel/locking/mutex.c

2 files changed, 3 insertions, 1 deletions

/* * xfrm4_mode_tunnel.c - Tunnel mode encapsulation for IPv4. * * Copyright (c) 2004-2006 Herbert Xu <herbert@gondor.apana.org.au> */ #include <linux/gfp.h> #include <linux/init.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/skbuff.h> #include <linux/stringify.h> #include <net/dst.h> #include <net/inet_ecn.h> #include <net/ip.h> #include <net/xfrm.h> static inline void ipip_ecn_decapsulate(struct sk_buff *skb) { struct iphdr *inner_iph = ipip_hdr(skb); if (INET_ECN_is_ce(XFRM_MODE_SKB_CB(skb)->tos)) IP_ECN_set_ce(inner_iph); } /* Add encapsulation header. * * The top IP header will be constructed per RFC 2401. */ static int xfrm4_mode_tunnel_output(struct xfrm_state *x, struct sk_buff *skb) { struct dst_entry *dst = skb_dst(skb); struct iphdr *top_iph; int flags; skb_set_network_header(skb, -x->props.header_len); skb->mac_header = skb->network_header + offsetof(struct iphdr, protocol); skb->transport_header = skb->network_header + sizeof(*top_iph); top_iph = ip_hdr(skb); top_iph->ihl = 5; top_iph->version = 4; top_iph->protocol = xfrm_af2proto(skb_dst(skb)->ops->family); /* DS disclosed */ top_iph->tos = INET_ECN_encapsulate(XFRM_MODE_SKB_CB(skb)->tos, XFRM_MODE_SKB_CB(skb)->tos); flags = x->props.flags; if (flags & XFRM_STATE_NOECN) IP_ECN_clear(top_iph); top_iph->frag_off = (flags & XFRM_STATE_NOPMTUDISC) ? 0 : (XFRM_MODE_SKB_CB(skb)->frag_off & htons(IP_DF)); ip_select_ident(top_iph, dst->child, NULL); top_iph->ttl = ip4_dst_hoplimit(dst->child); top_iph->saddr = x->props.saddr.a4; top_iph->daddr = x->id.daddr.a4; return 0; } static int xfrm4_mode_tunnel_input(struct xfrm_state *x, struct sk_buff *skb) { const unsigned char *old_mac; int err = -EINVAL; if (XFRM_MODE_SKB_CB(skb)->protocol != IPPROTO_IPIP) goto out; if (!pskb_may_pull(skb, sizeof(struct iphdr))) goto out; if (skb_cloned(skb) && (err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC))) goto out; if (x->props.flags & XFRM_STATE_DECAP_DSCP) ipv4_copy_dscp(XFRM_MODE_SKB_CB(skb)->tos, ipip_hdr(skb)); if (!(x->props.flags & XFRM_STATE_NOECN)) ipip_ecn_decapsulate(skb); old_mac = skb_mac_header(skb); skb_set_mac_header(skb, -skb->mac_len); memmove(skb_mac_header(skb), old_mac, skb->mac_len); skb_reset_network_header(skb); err = 0; out: return err; } static struct xfrm_mode xfrm4_tunnel_mode = { .input2 = xfrm4_mode_tunnel_input, .input = xfrm_prepare_input, .output2 = xfrm4_mode_tunnel_output, .output = xfrm4_prepare_output, .owner = THIS_MODULE, .encap = XFRM_MODE_TUNNEL, .flags = XFRM_MODE_FLAG_TUNNEL, }; static int __init xfrm4_mode_tunnel_init(void) { return xfrm_register_mode(&xfrm4_tunnel_mode, AF_INET); } static void __exit xfrm4_mode_tunnel_exit(void) { int err; err = xfrm_unregister_mode(&xfrm4_tunnel_mode, AF_INET); BUG_ON(err); } module_init(xfrm4_mode_tunnel_init); module_exit(xfrm4_mode_tunnel_exit); MODULE_LICENSE("GPL"); MODULE_ALIAS_XFRM_MODE(AF_INET, XFRM_MODE_TUNNEL);


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