David Carrillo-Cisneros 864c2357ca perf/core: Do not set cpuctx->cgrp for unscheduled cgroups ... Commit: db4a835601 ("perf/core: Set cgroup in CPU contexts for new cgroup events") failed to verify that event->cgrp is actually the scheduled cgroup in a CPU before setting cpuctx->cgrp. This patch fixes that. Now that there is a different path for scheduled and unscheduled cgroup, add a warning to catch when cpuctx->cgrp is still set after the last cgroup event has been unsheduled. To verify the bug: # Create 2 cgroups. mkdir /dev/cgroups/devices/g1 mkdir /dev/cgroups/devices/g2 # launch a task, bind it to a cpu and move it to g1 CPU=2 while :; do : ; done & P=$! taskset -pc $CPU $P echo $P > /dev/cgroups/devices/g1/tasks # monitor g2 (it runs no tasks) and observe output perf stat -e cycles -I 1000 -C $CPU -G g2 # time counts unit events 1.000091408 7,579,527 cycles g2 2.000350111 <not counted> cycles g2 3.000589181 <not counted> cycles g2 4.000771428 <not counted> cycles g2 # note first line that displays that a task run in g2, despite # g2 having no tasks. This is because cpuctx->cgrp was wrongly # set when context of new event was installed. # After applying the fix we obtain the right output: perf stat -e cycles -I 1000 -C $CPU -G g2 # time counts unit events 1.000119615 <not counted> cycles g2 2.000389430 <not counted> cycles g2 3.000590962 <not counted> cycles g2 Signed-off-by: David Carrillo-Cisneros <davidcc@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Kan Liang <kan.liang@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nilay Vaish <nilayvaish@gmail.com> Cc: Paul Turner <pjt@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vegard Nossum <vegard.nossum@gmail.com> Link: http://lkml.kernel.org/r/1478026378-86083-1-git-send-email-davidcc@google.com Signed-off-by: Ingo Molnar <mingo@kernel.org>		2016-11-15 14:18:22 +01:00
..
callchain.c	perf core: Per event callchain limit	2016-05-30 12:41:44 -03:00
core.c	perf/core: Do not set cpuctx->cgrp for unscheduled cgroups	2016-11-15 14:18:22 +01:00
hw_breakpoint.c	perf: Collapse and fix event_function_call() users	2016-01-21 18:54:24 +01:00
internal.h	bpf, events: fix offset in skb copy handler	2016-07-25 10:34:11 -07:00
Makefile
ring_buffer.c	perf/core: Fix aux_mmap_count vs aux_refcount order	2016-09-10 11:15:36 +02:00
uprobes.c	mm: replace get_user_pages_remote() write/force parameters with gup_flags	2016-10-19 08:12:02 -07:00