From: Peter Zijlstra <peterz@infradead.org>
To: kan.liang@linux.intel.com
Cc: tglx@linutronix.de, mingo@redhat.com, acme@kernel.org,
linux-kernel@vger.kernel.org, bp@alien8.de, ak@linux.intel.com,
eranian@google.com
Subject: Re: [PATCH 1/2] perf: Add munmap callback
Date: Thu, 25 Oct 2018 02:29:43 +0200 [thread overview]
Message-ID: <20181025002943.GT3109@worktop.c.hoisthospitality.com> (raw)
In-Reply-To: <20181024151116.30935-1-kan.liang@linux.intel.com>
On Wed, Oct 24, 2018 at 08:11:15AM -0700, kan.liang@linux.intel.com wrote:
> +void perf_event_munmap(void)
> +{
> + struct perf_cpu_context *cpuctx;
> + unsigned long flags;
> + struct pmu *pmu;
> +
> + local_irq_save(flags);
It is impossible to get here with IRQs already disabled.
> + list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
> + pmu = cpuctx->ctx.pmu;
> +
> + if (!pmu->munmap)
> + continue;
> +
> + perf_ctx_lock(cpuctx, cpuctx->task_ctx);
> + perf_pmu_disable(pmu);
> +
> + pmu->munmap();
> +
> + perf_pmu_enable(pmu);
> +
> + perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
> + }
> + local_irq_restore(flags);
> +}
> +
> static void perf_event_switch(struct task_struct *task,
> struct task_struct *next_prev, bool sched_in);
>
> diff --git a/mm/mmap.c b/mm/mmap.c
> index 5f2b2b184c60..61978ad8c480 100644
> --- a/mm/mmap.c
> +++ b/mm/mmap.c
> @@ -2777,6 +2777,7 @@ int do_munmap(struct mm_struct *mm, unsigned long start, size_t len,
> /*
> * Remove the vma's, and unmap the actual pages
> */
> + perf_event_munmap();
I think that if you add the munmap hook, you should do it right and at
least do it such that we can solve the other munmap problem.
> detach_vmas_to_be_unmapped(mm, vma, prev, end);
> unmap_region(mm, vma, prev, start, end);
>
> --
> 2.17.1
>
next prev parent reply other threads:[~2018-10-25 0:36 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-24 15:11 [PATCH 1/2] perf: Add munmap callback kan.liang
2018-10-24 15:11 ` [PATCH 2/2] perf/x86/intel: Fix missing physical address in large PEBS kan.liang
2018-10-24 16:23 ` [PATCH 1/2] perf: Add munmap callback Andi Kleen
2018-10-24 16:32 ` Arnaldo Carvalho de Melo
2018-10-24 18:12 ` Liang, Kan
2018-10-24 18:28 ` Andi Kleen
2018-10-25 0:31 ` Peter Zijlstra
2018-10-24 19:15 ` Arnaldo Carvalho de Melo
2018-10-24 19:30 ` Stephane Eranian
2018-10-25 0:23 ` Peter Zijlstra
2018-10-25 0:25 ` Stephane Eranian
2018-10-25 0:34 ` Peter Zijlstra
2018-10-25 0:44 ` Stephane Eranian
2018-11-01 14:09 ` Liang, Kan
2018-11-05 10:59 ` Stephane Eranian
2018-11-05 15:43 ` Liang, Kan
2018-11-06 15:00 ` Stephane Eranian
2018-11-06 16:47 ` Liang, Kan
2018-10-25 0:29 ` Peter Zijlstra [this message]
2018-10-25 14:00 ` Liang, Kan
2018-10-30 12:51 ` Peter Zijlstra
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