On Thu, Dec 21, 2017 at 10:08:44AM -0800, [email protected] wrote: > From: Kan Liang <[email protected]> > > The perf record has specific codes to calculate the ringbuffer position > for both overwrite and non-overwrite mode. > The perf top will support both modes later. > It is useful to make the specific codes generic. > > Introduce a new interface perf_mmap__read_init() to find ringbuffer > position. > Add a check for map->refcnt in perf_mmap__read_init(). > 'size' is needed for both perf_mmap__read_init() and perf_mmap__push(). > Have to calculate in each function.
it's 2 separate changes then plus 1 not mentioned in changelog.. could you please split this into separate patches: - Introduce a new interface perf_mmap__read_init ... - Add a check for map->refcnt in perf_mmap__read_init - add new EAGAIN return value logic thanks, jirka > > Signed-off-by: Kan Liang <[email protected]> > --- > tools/perf/util/mmap.c | 62 > ++++++++++++++++++++++++++++++++++---------------- > tools/perf/util/mmap.h | 2 ++ > 2 files changed, 45 insertions(+), 19 deletions(-) > > diff --git a/tools/perf/util/mmap.c b/tools/perf/util/mmap.c > index 05076e6..3fd4f3c 100644 > --- a/tools/perf/util/mmap.c > +++ b/tools/perf/util/mmap.c > @@ -267,41 +267,65 @@ static int overwrite_rb_find_range(void *buf, int mask, > u64 head, u64 *start, u6 > return -1; > } > > -int perf_mmap__push(struct perf_mmap *md, bool overwrite, > - void *to, int push(void *to, void *buf, size_t size)) > +/* > + * Report the start and end of the available data in ringbuffer > + */ > +int perf_mmap__read_init(struct perf_mmap *map, bool overwrite, > + u64 *start, u64 *end) > { > - u64 head = perf_mmap__read_head(md); > - u64 old = md->prev; > - u64 end = head, start = old; > - unsigned char *data = md->base + page_size; > + u64 head = perf_mmap__read_head(map); > + u64 old = map->prev; > + unsigned char *data = map->base + page_size; > unsigned long size; > - void *buf; > - int rc = 0; > > - start = overwrite ? head : old; > - end = overwrite ? old : head; > + /* > + * Check if event was unmapped due to a POLLHUP/POLLERR. > + */ > + if (!refcount_read(&map->refcnt)) > + return -EINVAL; > > - if (start == end) > - return 0; > + *start = overwrite ? head : old; > + *end = overwrite ? old : head; > > - size = end - start; > - if (size > (unsigned long)(md->mask) + 1) { > + if (*start == *end) > + return -EAGAIN; > + > + size = *end - *start; > + if (size > (unsigned long)(map->mask) + 1) { > if (!overwrite) { > WARN_ONCE(1, "failed to keep up with mmap data. (warn > only once)\n"); > > - md->prev = head; > - perf_mmap__consume(md, overwrite); > - return 0; > + map->prev = head; > + perf_mmap__consume(map, overwrite); > + return -EAGAIN; > } > > /* > * Backward ring buffer is full. We still have a chance to read > * most of data from it. > */ > - if (overwrite_rb_find_range(data, md->mask, head, &start, &end)) > - return -1; > + if (overwrite_rb_find_range(data, map->mask, head, start, end)) > + return -EINVAL; > } > > + return 0; > +} > + > +int perf_mmap__push(struct perf_mmap *md, bool overwrite, > + void *to, int push(void *to, void *buf, size_t size)) > +{ > + u64 head = perf_mmap__read_head(md); > + u64 end, start; > + unsigned char *data = md->base + page_size; > + unsigned long size; > + void *buf; > + int rc; > + > + rc = perf_mmap__read_init(md, overwrite, &start, &end); > + if (rc < 0) > + return (rc == -EAGAIN) ? 0 : -1; > + > + size = end - start; > if ((start & md->mask) + size != (end & md->mask)) { > buf = &data[start & md->mask]; > size = md->mask + 1 - (start & md->mask); > diff --git a/tools/perf/util/mmap.h b/tools/perf/util/mmap.h > index d640273..abe9b9f 100644 > --- a/tools/perf/util/mmap.h > +++ b/tools/perf/util/mmap.h > @@ -94,4 +94,6 @@ int perf_mmap__push(struct perf_mmap *md, bool backward, > > size_t perf_mmap__mmap_len(struct perf_mmap *map); > > +int perf_mmap__read_init(struct perf_mmap *map, bool overwrite, > + u64 *start, u64 *end); > #endif /*__PERF_MMAP_H */ > -- > 2.5.5 >
