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perf trace: Provide a better explanation when mmap fails
If we ask for a mmap lenght than the max configured via the relevant sysctl, provide a better warning, instead of just expanding the EPERM returned: [acme@ssdandy ~]$ trace -m 256 -e nanosleep sleep 2 Error: Operation not permitted. Hint: Check /proc/sys/kernel/perf_event_mlock_kb (516 kB) setting. Hint: Tried using 1028 kB. Hint: Try using a bigger -m/--mmap-pages value. [acme@ssdandy ~]$ trace -m 128 -e nanosleep sleep 2 2001.280 (2000.403 ms): nanosleep(rqtp: 0x7fff89a8a7f0) = 0 [acme@ssdandy ~]$ An upcoming patch will autotune the request for non-root users when -m is not used. Cc: Adrian Hunter <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: David Ahern <[email protected]> Cc: Don Zickus <[email protected]> Cc: Frederic Weisbecker <[email protected]> Cc: Jiri Olsa <[email protected]> Cc: Mike Galbraith <[email protected]> Cc: Namhyung Kim <[email protected]> Cc: Paul Mackerras <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Stephane Eranian <[email protected]> Link: http://lkml.kernel.org/n/[email protected] Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
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