Em Tue, Nov 17, 2020 at 12:00:42PM +0100, Jiri Olsa escreveu: > Allow mmap2 event to synthesize kernel image, > so we can synthesize kernel build id data in > following changes. > > It's enabled by new symbol_conf.buildid_mmap2 > bool, which will be switched in following > changes.
Why make this an option? MMAP2 goes back years: 13d7a2410fa637f45 (Stephane Eranian 2013-08-21 12:10:24 +0200 904) * The MMAP2 records are an augmented version of MMAP, they add 13d7a2410fa637f45 (Stephane Eranian 2013-08-21 12:10:24 +0200 905) * maj, min, ino numbers to be used to uniquely identify each mapping Also we unconditionally generate MMAP2 events if the kernel supports it, from evsel__config(): attr->mmap = track; attr->mmap2 = track && !perf_missing_features.mmap2; So perhaps we should reuse that logic? I.e. use mmap2 if the kernel supports it? - Arnaldo > Signed-off-by: Jiri Olsa <[email protected]> > --- > tools/perf/util/symbol_conf.h | 3 ++- > tools/perf/util/synthetic-events.c | 40 ++++++++++++++++++++---------- > 2 files changed, 29 insertions(+), 14 deletions(-) > > diff --git a/tools/perf/util/symbol_conf.h b/tools/perf/util/symbol_conf.h > index b916afb95ec5..b18f9c8dbb75 100644 > --- a/tools/perf/util/symbol_conf.h > +++ b/tools/perf/util/symbol_conf.h > @@ -42,7 +42,8 @@ struct symbol_conf { > report_block, > report_individual_block, > inline_name, > - disable_add2line_warn; > + disable_add2line_warn, > + buildid_mmap2; > const char *vmlinux_name, > *kallsyms_name, > *source_prefix, > diff --git a/tools/perf/util/synthetic-events.c > b/tools/perf/util/synthetic-events.c > index 8a23391558cf..872df6d6dbef 100644 > --- a/tools/perf/util/synthetic-events.c > +++ b/tools/perf/util/synthetic-events.c > @@ -988,11 +988,12 @@ static int __perf_event__synthesize_kernel_mmap(struct > perf_tool *tool, > perf_event__handler_t process, > struct machine *machine) > { > - size_t size; > + union perf_event *event; > + size_t size = symbol_conf.buildid_mmap2 ? > + sizeof(event->mmap2) : sizeof(event->mmap); > struct map *map = machine__kernel_map(machine); > struct kmap *kmap; > int err; > - union perf_event *event; > > if (map == NULL) > return -1; > @@ -1006,7 +1007,7 @@ static int __perf_event__synthesize_kernel_mmap(struct > perf_tool *tool, > * available use this, and after it is use this as a fallback for older > * kernels. > */ > - event = zalloc((sizeof(event->mmap) + machine->id_hdr_size)); > + event = zalloc(size + machine->id_hdr_size); > if (event == NULL) { > pr_debug("Not enough memory synthesizing mmap event " > "for kernel modules\n"); > @@ -1023,16 +1024,29 @@ static int > __perf_event__synthesize_kernel_mmap(struct perf_tool *tool, > event->header.misc = PERF_RECORD_MISC_GUEST_KERNEL; > } > > - size = snprintf(event->mmap.filename, sizeof(event->mmap.filename), > - "%s%s", machine->mmap_name, kmap->ref_reloc_sym->name) > + 1; > - size = PERF_ALIGN(size, sizeof(u64)); > - event->mmap.header.type = PERF_RECORD_MMAP; > - event->mmap.header.size = (sizeof(event->mmap) - > - (sizeof(event->mmap.filename) - size) + > machine->id_hdr_size); > - event->mmap.pgoff = kmap->ref_reloc_sym->addr; > - event->mmap.start = map->start; > - event->mmap.len = map->end - event->mmap.start; > - event->mmap.pid = machine->pid; > + if (symbol_conf.buildid_mmap2) { > + size = snprintf(event->mmap2.filename, > sizeof(event->mmap2.filename), > + "%s%s", machine->mmap_name, > kmap->ref_reloc_sym->name) + 1; > + size = PERF_ALIGN(size, sizeof(u64)); > + event->mmap2.header.type = PERF_RECORD_MMAP2; > + event->mmap2.header.size = (sizeof(event->mmap2) - > + (sizeof(event->mmap2.filename) - size) + > machine->id_hdr_size); > + event->mmap2.pgoff = kmap->ref_reloc_sym->addr; > + event->mmap2.start = map->start; > + event->mmap2.len = map->end - event->mmap.start; > + event->mmap2.pid = machine->pid; > + } else { > + size = snprintf(event->mmap.filename, > sizeof(event->mmap.filename), > + "%s%s", machine->mmap_name, > kmap->ref_reloc_sym->name) + 1; > + size = PERF_ALIGN(size, sizeof(u64)); > + event->mmap.header.type = PERF_RECORD_MMAP; > + event->mmap.header.size = (sizeof(event->mmap) - > + (sizeof(event->mmap.filename) - size) + > machine->id_hdr_size); > + event->mmap.pgoff = kmap->ref_reloc_sym->addr; > + event->mmap.start = map->start; > + event->mmap.len = map->end - event->mmap.start; > + event->mmap.pid = machine->pid; > + } > > err = perf_tool__process_synth_event(tool, event, machine, process); > free(event); > -- > 2.26.2 > -- - Arnaldo
