From ef824fa129b7579f56b92d466ecda2e378879806 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Mon, 8 Apr 2013 19:00:38 -0700 Subject: perf: make perf_event cgroup hierarchical perf_event is one of a couple remaining cgroup controllers with broken hierarchy support. Converting it to support hierarchy is almost trivial. The only thing necessary is to consider a task belonging to a descendant cgroup as a match. IOW, if the cgroup of the currently executing task (@cpuctx->cgrp) equals or is a descendant of the event's cgroup (@event->cgrp), then the event should be enabled. Implement hierarchy support and remove .broken_hierarchy tag along with the incorrect comment on what needs to be done for hierarchy support. Signed-off-by: Tejun Heo Cc: Peter Zijlstra Cc: Paul Mackerras Cc: Ingo Molnar Cc: Arnaldo Carvalho de Melo Cc: Stephane Eranian Cc: Namhyung Kim --- kernel/events/core.c | 24 ++++++++++++++++-------- 1 file changed, 16 insertions(+), 8 deletions(-) (limited to 'kernel/events') diff --git a/kernel/events/core.c b/kernel/events/core.c index b0cd86501c30..310ec19d968a 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -251,7 +251,22 @@ perf_cgroup_match(struct perf_event *event) struct perf_event_context *ctx = event->ctx; struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); - return !event->cgrp || event->cgrp == cpuctx->cgrp; + /* @event doesn't care about cgroup */ + if (!event->cgrp) + return true; + + /* wants specific cgroup scope but @cpuctx isn't associated with any */ + if (!cpuctx->cgrp) + return false; + + /* + * Cgroup scoping is recursive. An event enabled for a cgroup is + * also enabled for all its descendant cgroups. If @cpuctx's + * cgroup is a descendant of @event's (the test covers identity + * case), it's a match. + */ + return cgroup_is_descendant(cpuctx->cgrp->css.cgroup, + event->cgrp->css.cgroup); } static inline bool perf_tryget_cgroup(struct perf_event *event) @@ -7509,12 +7524,5 @@ struct cgroup_subsys perf_subsys = { .css_free = perf_cgroup_css_free, .exit = perf_cgroup_exit, .attach = perf_cgroup_attach, - - /* - * perf_event cgroup doesn't handle nesting correctly. - * ctx->nr_cgroups adjustments should be propagated through the - * cgroup hierarchy. Fix it and remove the following. - */ - .broken_hierarchy = true, }; #endif /* CONFIG_CGROUP_PERF */ -- cgit v1.2.3-70-g09d2