Messages in this thread | | | From | Menglong Dong <> | Date | Wed, 1 Jun 2022 11:27:41 +0800 | Subject | Re: [PATCH net-next v2 2/3] net: skb: use auto-generation to convert skb drop reason to string |
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On Tue, May 31, 2022 at 4:13 AM Jakub Kicinski <kuba@kernel.org> wrote: > > On Mon, 30 May 2022 16:12:00 +0800 menglong8.dong@gmail.com wrote: > > From: Menglong Dong <imagedong@tencent.com> > > > > It is annoying to add new skb drop reasons to 'enum skb_drop_reason' > > and TRACE_SKB_DROP_REASON in trace/event/skb.h, and it's easy to forget > > to add the new reasons we added to TRACE_SKB_DROP_REASON. > > > > TRACE_SKB_DROP_REASON is used to convert drop reason of type number > > to string. For now, the string we passed to user space is exactly the > > same as the name in 'enum skb_drop_reason' with a 'SKB_DROP_REASON_' > > prefix. Therefore, we can use 'auto-generation' to generate these > > drop reasons to string at build time. > > > > The new header 'dropreason_str.h' > > Not any more. > > > will be generated, and the > > __DEFINE_SKB_DROP_REASON() in it can do the converting job. Meanwhile, > > we use a global array to store these string, which can be used both > > in drop_monitor and 'kfree_skb' tracepoint. > > > diff --git a/include/net/dropreason.h b/include/net/dropreason.h > > index ecd18b7b1364..460de425297c 100644 > > --- a/include/net/dropreason.h > > +++ b/include/net/dropreason.h > > @@ -3,6 +3,8 @@ > > #ifndef _LINUX_DROPREASON_H > > #define _LINUX_DROPREASON_H > > > > +#include <linux/kernel.h> > > Why?
Oh, you noticed it. To simplify the code in dropreason_str.c, as EXPORT_SYMBOL() is used. Okay, I'll move it to the generation part.
> > > +dropreason_str.c > > \ No newline at end of file > > Heed the warning. > > > diff --git a/net/core/Makefile b/net/core/Makefile > > index a8e4f737692b..3c7f99ff6d89 100644 > > --- a/net/core/Makefile > > +++ b/net/core/Makefile > > @@ -4,7 +4,8 @@ > > # > > > > obj-y := sock.o request_sock.o skbuff.o datagram.o stream.o scm.o \ > > - gen_stats.o gen_estimator.o net_namespace.o secure_seq.o flow_dissector.o > > + gen_stats.o gen_estimator.o net_namespace.o secure_seq.o \ > > + flow_dissector.o dropreason_str.o > > > > obj-$(CONFIG_SYSCTL) += sysctl_net_core.o > > > > @@ -39,3 +40,23 @@ obj-$(CONFIG_NET_SOCK_MSG) += skmsg.o > > obj-$(CONFIG_BPF_SYSCALL) += sock_map.o > > obj-$(CONFIG_BPF_SYSCALL) += bpf_sk_storage.o > > obj-$(CONFIG_OF) += of_net.o > > + > > +clean-files := dropreason_str.c > > + > > +quiet_cmd_dropreason_str = GEN $@ > > +cmd_dropreason_str = awk -F ',' 'BEGIN{ print "\#include <net/dropreason.h>\n"; \ > > + print "const char * const drop_reasons[] = {" }\ > > + /^enum skb_drop/ { dr=1; }\ > > + /\}\;/ { dr=0; }\ > > + /^\tSKB_DROP_REASON_/ {\ > > + if (dr) {\ > > + sub(/\tSKB_DROP_REASON_/, "", $$1);\ > > + printf "\t[SKB_DROP_REASON_%s] = \"%s\",\n", $$1, $$1;\ > > + }\ > > + } \ > > + END{ print "};\nEXPORT_SYMBOL(drop_reasons);" }' $< > $@ > > + > > +$(obj)/dropreason_str.c: $(srctree)/include/net/dropreason.h > > + $(call cmd,dropreason_str) > > I'm getting this: > > awk: cmd. line:1: warning: regexp escape sequence `\;' is not a known regexp operator >
Enn...I think this warning comes from the "/\}\;/ { dr=0; }\" part. Let me do more investigation.
Thanks! Menglong Dong
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