linux-kernel - Re: [PATCH v4 RESEND 3/5] perf/x86/lbr: Move cpuc->lbr

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Message-ID: <CAM9d7ci7qj47xDC3z2AzYGjnFdPRNsuEPGivZ1_re-XGhoBwMg@mail.gmail.com>
Date:   Wed, 24 Mar 2021 10:32:41 +0900
From:   Namhyung Kim <namhyung@...nel.org>
To:     Like Xu <like.xu@...ux.intel.com>
Cc:     Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Borislav Petkov <bp@...en8.de>,
        Kan Liang <kan.liang@...ux.intel.com>, x86@...nel.org,
        linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v4 RESEND 3/5] perf/x86/lbr: Move cpuc->lbr_xsave
 allocation out of sleeping region

Hello,

On Mon, Mar 22, 2021 at 3:14 PM Like Xu <like.xu@...ux.intel.com> wrote:
> +void reserve_lbr_buffers(struct perf_event *event)
> +{
> +       struct kmem_cache *kmem_cache = x86_get_pmu()->task_ctx_cache;
> +       struct cpu_hw_events *cpuc;
> +       int cpu;
> +
> +       if (!static_cpu_has(X86_FEATURE_ARCH_LBR))
> +               return;
> +
> +       for_each_possible_cpu(cpu) {
> +               cpuc = per_cpu_ptr(&cpu_hw_events, cpu);
> +               if (kmem_cache && !cpuc->lbr_xsave && !event->attr.precise_ip)
> +                       cpuc->lbr_xsave = kmem_cache_alloc(kmem_cache, GFP_KERNEL);
> +       }
> +}

I think we should use kmem_cache_alloc_node().

Thanks,
Namhyung