On Fri, May 5, 2023 at 1:43 PM Jiri Olsa <olsajiri@xxxxxxxxx> wrote: > > On Fri, May 05, 2023 at 10:04:47AM -0700, Ian Rogers wrote: > > On Fri, May 5, 2023 at 9:56 AM Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> wrote: > > > > > > Em Fri, May 05, 2023 at 10:33:15AM -0300, Arnaldo Carvalho de Melo escreveu: > > > > Em Fri, May 05, 2023 at 01:03:14AM +0200, Jiri Olsa escreveu: > > > > That with the preserve_access_index isn't needed, we need just the > > > > fields that we access in the tools, right? > > > > > > I'm now doing build test this in many distro containers, without the two > > > reverts, i.e. BPF skels continue as opt-out as in my pull request, to > > > test build and also for the functionality tests on the tools using such > > > bpf skels, see below, no touching of vmlinux nor BTF data during the > > > build. > > > > > > - Arnaldo > > > > > > From 882adaee50bc27f85374aeb2fbaa5b76bef60d05 Mon Sep 17 00:00:00 2001 > > > From: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> > > > Date: Thu, 4 May 2023 19:03:51 -0300 > > > Subject: [PATCH 1/1] perf bpf skels: Stop using vmlinux.h generated from BTF, > > > use subset of used structs + CO-RE > > > > > > Linus reported a build break due to using a vmlinux without a BTF elf > > > section to generate the vmlinux.h header with bpftool for use in the BPF > > > tools in tools/perf/util/bpf_skel/*.bpf.c. > > > > > > Instead add a vmlinux.h file with the structs needed with the fields the > > > tools need, marking the structs with __attribute__((preserve_access_index)), > > > so that libbpf's CO-RE code can fixup the struct field offsets. > > > > > > In some cases the vmlinux.h file that was being generated by bpftool > > > from the kernel BTF information was not needed at all, just including > > > linux/bpf.h, sometimes linux/perf_event.h was enough as non-UAPI > > > types were not being used. > > > > > > To keep te patch small, include those UAPI headers from the trimmed down > > > vmlinux.h file, that then provides the tools with just the structs and > > > the subset of its fields needed for them. > > > > > > Testing it: > > > > > > # perf lock contention -b find / > /dev/null > > I tested perf lock con -abv -L rcu_state sleep 1 > and needed fix below > > jirka I thought this was fixed by: https://lore.kernel.org/lkml/20230427234833.1576130-1-namhyung@xxxxxxxxxx/ but I think that is just in perf-tools-next. Thanks, Ian > --- > From b12aea55f1171dc09cde2957f9019c84bda7adbb Mon Sep 17 00:00:00 2001 > From: Jiri Olsa <jolsa@xxxxxxxxxx> > Date: Fri, 5 May 2023 13:28:46 +0200 > Subject: [PATCH] perf tools: Fix lock_contention bpf program > > We need to define empty 'struct rq' so the runqueues gets > resolved properly: > > # ./perf lock con -b > libbpf: extern (var ksym) 'runqueues': incompatible types, expected [99] fwd rq, but kernel has [19783] struct rq > libbpf: failed to load object 'lock_contention_bpf' > libbpf: failed to load BPF skeleton 'lock_contention_bpf': -22 > Failed to load lock-contention BPF skeleton > > Also rq__old/rq__new need additional '_' so the suffix is ignored > properly. > > Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx> > --- > tools/perf/util/bpf_skel/lock_contention.bpf.c | 10 ++++++---- > 1 file changed, 6 insertions(+), 4 deletions(-) > > diff --git a/tools/perf/util/bpf_skel/lock_contention.bpf.c b/tools/perf/util/bpf_skel/lock_contention.bpf.c > index 8911e2a077d8..c2bf24c68c14 100644 > --- a/tools/perf/util/bpf_skel/lock_contention.bpf.c > +++ b/tools/perf/util/bpf_skel/lock_contention.bpf.c > @@ -416,13 +416,15 @@ int contention_end(u64 *ctx) > return 0; > } > > +struct rq {}; > + > extern struct rq runqueues __ksym; > > -struct rq__old { > +struct rq___old { > raw_spinlock_t lock; > } __attribute__((preserve_access_index)); > > -struct rq__new { > +struct rq___new { > raw_spinlock_t __lock; > } __attribute__((preserve_access_index)); > > @@ -434,8 +436,8 @@ int BPF_PROG(collect_lock_syms) > > for (int i = 0; i < MAX_CPUS; i++) { > struct rq *rq = bpf_per_cpu_ptr(&runqueues, i); > - struct rq__new *rq_new = (void *)rq; > - struct rq__old *rq_old = (void *)rq; > + struct rq___new *rq_new = (void *)rq; > + struct rq___old *rq_old = (void *)rq; > > if (rq == NULL) > break; > -- > 2.40.1 >
