Messages in this thread Patch in this message | | | From | linxiulei@gmail ... | Subject | [PATCH v2] perf/core: Fix installing cgroup event into cpu | Date | Wed, 24 Jan 2018 15:50:10 +0800 |
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From: "leilei.lin" <leilei.lin@alibaba-inc.com>
Do not install cgroup event into the CPU context if the cgroup is not running on this CPU
While there is no task of cgroup running specified CPU, current kernel still install cgroup event into CPU context, that causes another cgroup event can't be installed into this CPU.
Signed-off-by: leilei.lin <leilei.lin@alibaba-inc.com> --- kernel/events/core.c | 44 +++++++++++++++++++++++++++++++------------- 1 file changed, 31 insertions(+), 13 deletions(-)
diff --git a/kernel/events/core.c b/kernel/events/core.c index 4df5b69..f766b60 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -933,31 +933,36 @@ list_update_cgroup_event(struct perf_event *event, { struct perf_cpu_context *cpuctx; struct list_head *cpuctx_entry; + struct perf_cgroup *cgrp; if (!is_cgroup_event(event)) return; - if (add && ctx->nr_cgroups++) - return; - else if (!add && --ctx->nr_cgroups) - return; /* * Because cgroup events are always per-cpu events, * this will always be called from the right CPU. */ cpuctx = __get_cpu_context(ctx); - cpuctx_entry = &cpuctx->cgrp_cpuctx_entry; - /* cpuctx->cgrp is NULL unless a cgroup event is active in this CPU .*/ - if (add) { - struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx); + cgrp = perf_cgroup_from_task(current, ctx); - list_add(cpuctx_entry, this_cpu_ptr(&cgrp_cpuctx_list)); - if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup)) + /* cpuctx->cgrp is NULL unless a cgroup event is running in this CPU .*/ + if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup)) { + if (add) cpuctx->cgrp = cgrp; - } else { - list_del(cpuctx_entry); - cpuctx->cgrp = NULL; + else + cpuctx->cgrp = NULL; } + + if (add && ctx->nr_cgroups++) + return; + else if (!add && --ctx->nr_cgroups) + return; + + cpuctx_entry = &cpuctx->cgrp_cpuctx_entry; + if (add) + list_add(cpuctx_entry, this_cpu_ptr(&cgrp_cpuctx_list)); + else + list_del(cpuctx_entry); } #else /* !CONFIG_CGROUP_PERF */ @@ -2284,6 +2289,7 @@ static int __perf_install_in_context(void *info) struct perf_event_context *ctx = event->ctx; struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); struct perf_event_context *task_ctx = cpuctx->task_ctx; + struct perf_cgroup *cgrp; bool reprogram = true; int ret = 0; @@ -2311,6 +2317,18 @@ static int __perf_install_in_context(void *info) raw_spin_lock(&task_ctx->lock); } + if (is_cgroup_event(event)) { + /* + * Only care about cgroup events. + * + * If only the task belongs to cgroup of this event, + * we will continue the installment + */ + cgrp = perf_cgroup_from_task(current, ctx); + reprogram = cgroup_is_descendant(cgrp->css.cgroup, + event->cgrp->css.cgroup); + } + if (reprogram) { ctx_sched_out(ctx, cpuctx, EVENT_TIME); add_event_to_ctx(event, ctx); -- 2.8.4.31.g9ed660f
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