From: Kan Liang <[email protected]> The new function perf_mmap__read_init() is factored out from perf_mmap__push().
It is to calculate the 'start' and 'end' of the available data in ringbuffer. No functional change. Signed-off-by: Kan Liang <[email protected]> --- tools/perf/util/mmap.c | 37 +++++++++++++++++++++++++++---------- tools/perf/util/mmap.h | 2 ++ 2 files changed, 29 insertions(+), 10 deletions(-) diff --git a/tools/perf/util/mmap.c b/tools/perf/util/mmap.c index fbbbe87..c19a4e6 100644 --- a/tools/perf/util/mmap.c +++ b/tools/perf/util/mmap.c @@ -267,24 +267,24 @@ 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 *md, bool overwrite, + u64 *startp, u64 *endp) { u64 head = perf_mmap__read_head(md); u64 old = md->prev; - u64 end, start; unsigned char *data = md->base + page_size; unsigned long size; - void *buf; - int rc = 0; - start = overwrite ? head : old; - end = overwrite ? old : head; + *startp = overwrite ? head : old; + *endp = overwrite ? old : head; - if (start == end) + if (*startp == *endp) return 0; - size = end - start; + size = *endp - *startp; if (size > (unsigned long)(md->mask) + 1) { if (!overwrite) { WARN_ONCE(1, "failed to keep up with mmap data. (warn only once)\n"); @@ -298,10 +298,27 @@ int perf_mmap__push(struct perf_mmap *md, bool overwrite, * 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)) + if (overwrite_rb_find_range(data, md->mask, head, startp, endp)) return -1; } + return 1; +} + +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 = 0; + + rc = perf_mmap__read_init(md, overwrite, &start, &end); + if (rc < 1) + return rc; + size = end - start; if ((start & md->mask) + size != (end & md->mask)) { diff --git a/tools/perf/util/mmap.h b/tools/perf/util/mmap.h index e43d7b5..9ab2b48 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 *md, bool overwrite, + u64 *startp, u64 *endp); #endif /*__PERF_MMAP_H */ -- 2.5.5
