• Arnaldo Carvalho de Melo's avatar
    perf evlist: Drop redundant evsel->overwrite indicator · 32a951b4
    Arnaldo Carvalho de Melo authored
    evsel->overwrite indicator means an event should be put into
    overwritable ring buffer. In current implementation, it equals to
    evsel->attr.write_backward. To reduce compliexity, remove
    evsel->overwrite, use evsel->attr.write_backward instead.
    
    In addition, in __perf_evsel__open(), if kernel doesn't support
    write_backward and user explicitly set it in evsel, don't fallback
    like other missing feature, since it is meaningless to fall back to
    a forward ring buffer in this case: we are unable to stably read
    from an forward overwritable ring buffer.
    
    Cc: He Kuang <hekuang@huawei.com>
    Cc: Jiri Olsa <jolsa@kernel.org>
    Cc: Masami Hiramatsu <mhiramat@kernel.org>
    Cc: Namhyung Kim <namhyung@kernel.org>
    Cc: Nilay Vaish <nilayvaish@gmail.com>
    Cc: Wang Nan <wangnan0@huawei.com>
    Cc: Zefan Li <lizefan@huawei.com>
    Cc: pi3orama@163.com
    Link: http://lkml.kernel.org/r/1468485287-33422-2-git-send-email-wangnan0@huawei.comSigned-off-by: default avatarWang Nan <wangnan0@huawei.com>
    Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
    32a951b4
backward-ring-buffer.c 3.37 KB