Hi Arnaldo,
On Fri, Oct 02, 2015 at 03:44:33PM -0300, Arnaldo Carvalho de Melo wrote:
> Em Fri, Oct 02, 2015 at 02:18:43PM +0900, Namhyung Kim escreveu:
> > It is more convenient saving mmap length rather than (bit) mask. With
> > this patch, we can eliminate dependency to perf_evlist other than
> > getting mmap_desc for dealing with mmaps. The mask and length can be
> > converted using perf_evlist__mmap_mask/len().
> >
> > Cc: Jiri Olsa <jo...@redhat.com>
> > Cc: Adrian Hunter <adrian.hun...@intel.com>
> > Signed-off-by: Namhyung Kim <namhy...@kernel.org>
> > ---
> > tools/perf/util/evlist.c | 31 +++++++++++++++++++++++++------
> > 1 file changed, 25 insertions(+), 6 deletions(-)
> >
> > diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
> > index c5180a29db1b..e46adcd5b408 100644
> > --- a/tools/perf/util/evlist.c
> > +++ b/tools/perf/util/evlist.c
> > @@ -29,6 +29,8 @@
> >
> > static void perf_evlist__mmap_put(struct perf_evlist *evlist, int idx);
> > static void __perf_evlist__munmap(struct perf_evlist *evlist, int idx);
> > +static size_t perf_evlist__mmap_mask(size_t len);
> > +static size_t perf_evlist__mmap_len(size_t mask);
>
> Are these "perf_evlist" methods? I don't think so, those are related to
> "perf_mmap".
Agreed.
>
> > #define FD(e, x, y) (*(int *)xyarray__entry(e->fd, x, y))
> > #define SID(e, x, y) xyarray__entry(e->sample_id, x, y)
> > @@ -871,7 +873,9 @@ void __weak auxtrace_mmap_params__set_idx(
> > static void __perf_evlist__munmap(struct perf_evlist *evlist, int idx)
> > {
> > if (evlist->mmap[idx].base != NULL) {
> > - munmap(evlist->mmap[idx].base, evlist->mmap_len);
> > + size_t mmap_len = perf_evlist__mmap_len(evlist->mmap[idx].mask);
>
> I.e. here you could have it as:
>
> size_t mmap_len = perf_mmap__len(evlist->mmap[idx]);
OK.
>
> > +
> > + munmap(evlist->mmap[idx].base, mmap_len);
> > evlist->mmap[idx].base = NULL;
> > atomic_set(&evlist->mmap[idx].refcnt, 0);
> > }
> > @@ -901,8 +905,8 @@ static int perf_evlist__alloc_mmap(struct perf_evlist
> > *evlist)
> > }
> >
> > struct mmap_params {
> > - int prot;
> > - int mask;
> > + int prot;
> > + size_t len;
> > struct auxtrace_mmap_params auxtrace_mp;
> > };
> >
> > @@ -924,8 +928,8 @@ static int __perf_evlist__mmap(struct perf_evlist
> > *evlist, int idx,
> > */
> > atomic_set(&evlist->mmap[idx].refcnt, 2);
> > evlist->mmap[idx].prev = 0;
> > - evlist->mmap[idx].mask = mp->mask;
> > - evlist->mmap[idx].base = mmap(NULL, evlist->mmap_len, mp->prot,
> > + evlist->mmap[idx].mask = perf_evlist__mmap_mask(mp->len);
>
> Here, since you're not using a perf_mmap instance, but the calculation
> is relative to a perf_mmap property, we would use:
>
> evlist->mmap[idx].mask = __perf_mmap__mask(mp->len);
Will change.
Thanks,
Namhyung
>
>
> > + evlist->mmap[idx].base = mmap(NULL, mp->len, mp->prot,
> > MAP_SHARED, fd, 0);
> > if (evlist->mmap[idx].base == MAP_FAILED) {
> > pr_debug2("failed to mmap perf event ring buffer, error %d\n",
> > @@ -1071,6 +1075,21 @@ static size_t perf_evlist__mmap_size(unsigned long
> > pages)
> > return (pages + 1) * page_size;
> > }
> >
> > +static size_t perf_evlist__mmap_mask(size_t len)
> > +{
> > + BUG_ON(len <= page_size);
> > + BUG_ON((len % page_size) != 0);
> > +
> > + return len - page_size - 1;
> > +}
> > +
> > +static size_t perf_evlist__mmap_len(size_t mask)
> > +{
> > + BUG_ON(((mask + 1) % page_size) != 0);
> > +
> > + return mask + 1 + page_size;
> > +}
> > +
> > static long parse_pages_arg(const char *str, unsigned long min,
> > unsigned long max)
> > {
> > @@ -1176,7 +1195,7 @@ int perf_evlist__mmap_ex(struct perf_evlist *evlist,
> > unsigned int pages,
> > evlist->overwrite = overwrite;
> > evlist->mmap_len = perf_evlist__mmap_size(pages);
> > pr_debug("mmap size %zuB\n", evlist->mmap_len);
> > - mp.mask = evlist->mmap_len - page_size - 1;
> > + mp.len = evlist->mmap_len;
> >
> > auxtrace_mmap_params__init(&mp.auxtrace_mp, evlist->mmap_len,
> > auxtrace_pages, auxtrace_overwrite);
> > --
> > 2.6.0
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