Re: [PATCH 2/2] perf record: wrong size in perf_record_mmap for last kernel module

[Arnaldo Carvalho de Melo <acme@kernel.org>]

Em Mon, Jul 24, 2017 at 03:20:07PM -0300, Arnaldo Carvalho de Melo escreveu:
> Em Mon, Jul 24, 2017 at 04:35:14PM +0200, Thomas Richter escreveu:
> > +++ b/tools/perf/util/machine.c
> > @@ -20,6 +20,7 @@
> > +#include <sys/user.h>

no need for this header, see below.

> > -static int machine__create_module(void *arg, const char *name, u64 start)
> > +static int machine__create_module(void *arg, const char *name, u64 start, u64 size)
> >  {
> > @@ -1148,6 +1149,7 @@ static int machine__create_module(void *arg, const char *name, u64 start)
> >  	map = machine__findnew_module_map(machine, start, name);
> >  	if (map == NULL)
> >  		return -1;
> > +	map->end = roundup(start + size, PAGE_SIZE);

We have the page_size variable, that gets its value at:

tools/perf/perf.c:	page_size = sysconf(_SC_PAGE_SIZE);

always available, determined at run time.

Also, what is the reason for the roundup?

> >  	dso__kernel_module_get_build_id(map->dso, machine->root_dir);

- Arnaldo