| From | kan.liang@intel ... | Subject | [PATCH V5 07/17] perf mmap: introduce perf_mmap__read_done | Date | Thu, 18 Jan 2018 13:26:22 -0800 |
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From: Kan Liang <kan.liang@intel.com>
The direction of overwrite mode is backward. The last perf_mmap__read() will set tail to map->prev. Need to correct the map->prev to head which is the end of next read.
It will be used later.
Signed-off-by: Kan Liang <kan.liang@intel.com> --- tools/perf/util/mmap.c | 11 +++++++++++ tools/perf/util/mmap.h | 1 + 2 files changed, 12 insertions(+)
diff --git a/tools/perf/util/mmap.c b/tools/perf/util/mmap.c index 125bfda..4f59eae 100644 --- a/tools/perf/util/mmap.c +++ b/tools/perf/util/mmap.c @@ -338,3 +338,14 @@ int perf_mmap__push(struct perf_mmap *md, bool overwrite, out: return rc; } + +/* + * Mandatory for overwrite mode + * The direction of overwrite mode is backward. + * The last perf_mmap__read() will set tail to map->prev. + * Need to correct the map->prev to head which is the end of next read. + */ +void perf_mmap__read_done(struct perf_mmap *map) +{ + map->prev = perf_mmap__read_head(map); +} diff --git a/tools/perf/util/mmap.h b/tools/perf/util/mmap.h index 9ab2b48..95549d4 100644 --- a/tools/perf/util/mmap.h +++ b/tools/perf/util/mmap.h @@ -96,4 +96,5 @@ 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); +void perf_mmap__read_done(struct perf_mmap *map); #endif /*__PERF_MMAP_H */ -- 2.5.5
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