Re: [PATCH RESEND] perf/core: Fix installing cgroup event into cpu

[kbuild test robot]

Hi leilei.lin,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on tip/perf/core]
[also build test ERROR on v4.15-rc9 next-20180119]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/linxiulei-gmail-com/perf-core-Fix-installing-cgroup-event-into-cpu/20180126-083327
config: x86_64-randconfig-g0-01260853 (attached as .config)
compiler: gcc-4.9 (Debian 4.9.4-2) 4.9.4
reproduce:
        # save the attached .config to linux build tree
        make ARCH=x86_64 

All errors (new ones prefixed by >>):

   kernel//events/core.c: In function '__perf_install_in_context':
   kernel//events/core.c:2315:11: error: 'struct perf_event' has no member named 'cgrp'
     if (event->cgrp) {
              ^
>> kernel//events/core.c:2322:3: error: implicit declaration of function 'perf_cgroup_from_task' [-Werror=implicit-function-declaration]
      cgrp = perf_cgroup_from_task(current, ctx);
      ^
   kernel//events/core.c:2322:8: warning: assignment makes pointer from integer without a cast
      cgrp = perf_cgroup_from_task(current, ctx);
           ^
>> kernel//events/core.c:2323:33: error: dereferencing pointer to incomplete type
      if (!cgroup_is_descendant(cgrp->css.cgroup,
                                    ^
   kernel//events/core.c:2324:11: error: 'struct perf_event' has no member named 'cgrp'
         event->cgrp->css.cgroup))
              ^
   cc1: some warnings being treated as errors

vim +/perf_cgroup_from_task +2322 kernel//events/core.c

  2274	
  2275	/*
  2276	 * Cross CPU call to install and enable a performance event
  2277	 *
  2278	 * Very similar to remote_function() + event_function() but cannot assume that
  2279	 * things like ctx->is_active and cpuctx->task_ctx are set.
  2280	 */
  2281	static int  __perf_install_in_context(void *info)
  2282	{
  2283		struct perf_event *event = info;
  2284		struct perf_event_context *ctx = event->ctx;
  2285		struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
  2286		struct perf_event_context *task_ctx = cpuctx->task_ctx;
  2287		struct perf_cgroup *cgrp;
  2288		bool reprogram = true;
  2289		int ret = 0;
  2290	
  2291		raw_spin_lock(&cpuctx->ctx.lock);
  2292		if (ctx->task) {
  2293			raw_spin_lock(&ctx->lock);
  2294			task_ctx = ctx;
  2295	
  2296			reprogram = (ctx->task == current);
  2297	
  2298			/*
  2299			 * If the task is running, it must be running on this CPU,
  2300			 * otherwise we cannot reprogram things.
  2301			 *
  2302			 * If its not running, we don't care, ctx->lock will
  2303			 * serialize against it becoming runnable.
  2304			 */
  2305			if (task_curr(ctx->task) && !reprogram) {
  2306				ret = -ESRCH;
  2307				goto unlock;
  2308			}
  2309	
  2310			WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
  2311		} else if (task_ctx) {
  2312			raw_spin_lock(&task_ctx->lock);
  2313		}
  2314	
> 2315		if (event->cgrp) {
  2316			/*
  2317			 * Only care about cgroup events.
  2318			 *
  2319			 * If only the task belongs to cgroup of this event,
  2320			 * we will continue the installment
  2321			 */
> 2322			cgrp = perf_cgroup_from_task(current, ctx);
> 2323			if (!cgroup_is_descendant(cgrp->css.cgroup,
  2324						event->cgrp->css.cgroup))
  2325				goto unlock;
  2326		}
  2327	
  2328		if (reprogram) {
  2329			ctx_sched_out(ctx, cpuctx, EVENT_TIME);
  2330			add_event_to_ctx(event, ctx);
  2331			ctx_resched(cpuctx, task_ctx, get_event_type(event));
  2332		} else {
  2333			add_event_to_ctx(event, ctx);
  2334		}
  2335	
  2336	unlock:
  2337		perf_ctx_unlock(cpuctx, task_ctx);
  2338	
  2339		return ret;
  2340	}
  2341	

---
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