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From: Nilay Vaish <nilayvaish@gmail.com>
Date: Mon, 10 Oct 2016 12:51:57 -0500
Message-ID: <CACbG30-oZNg4r3+24hb_iOSRo_gCrYYQXbN74G0W12u9vJ3j9Q@mail.gmail.com>
Subject: Re: [PATCH v3 13/18] x86/intel_rdt: Add mkdir to resctrl file system
To: Fenghua Yu <fenghua.yu@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
        "H. Peter Anvin" <h.peter.anvin@intel.com>,
        Ingo Molnar <mingo@elte.hu>, Tony Luck <tony.luck@intel.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Stephane Eranian <eranian@google.com>, Borislav Petkov <bp@suse.de>,
        Dave Hansen <dave.hansen@intel.com>, Shaohua Li <shli@fb.com>,
        David Carrillo-Cisneros <davidcc@google.com>,
        Ravi V Shankar <ravi.v.shankar@intel.com>,
        Sai Prakhya <sai.praneeth.prakhya@intel.com>,
        Vikas Shivappa <vikas.shivappa@linux.intel.com>,
        linux-kernel <linux-kernel@vger.kernel.org>, x86 <x86@kernel.org>
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Sender: linux-kernel-owner@vger.kernel.org
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On 7 October 2016 at 21:45, Fenghua Yu <fenghua.yu@intel.com> wrote:
> From: Fenghua Yu <fenghua.yu@intel.com>
> diff --git a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
> index 28df92e..efcbfe7 100644
> --- a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
> +++ b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
> @@ -36,6 +36,52 @@ struct kernfs_root *rdt_root;
>  struct rdtgroup rdtgroup_default;
>  LIST_HEAD(rdt_all_groups);
>
> +/*
> + * Trivial allocator for CLOSIDs. Since h/w only supports
> + * a small number, we can keep a bitmap of free CLOSIDs in
> + * a single integer.
> + */
> +static int closid_free_map;
> +
> +static void closid_init(void)
> +{
> +       closid_free_map = BIT_MASK(rdt_max_closid) - 1;
> +
> +       /* CLOSID 0 is always reserved for the default group */
> +       closid_free_map &= ~1;
> +}
> +
> +int closid_alloc(void)
> +{
> +       int closid = ffs(closid_free_map);
> +
> +       if (closid == 0)
> +               return -ENOSPC;
> +       closid--;
> +       closid_free_map &= ~(1 << closid);
> +
> +       return closid;
> +}
> +
> +static void closid_free(int closid)
> +{
> +       closid_free_map |= 1 << closid;
> +}
> +
> +static struct rdtgroup *rdtgroup_alloc(void)
> +{
> +       struct rdtgroup *rdtgrp;
> +
> +       rdtgrp = kzalloc(sizeof(*rdtgrp), GFP_KERNEL);
> +
> +       return rdtgrp;
> +}
> +
> +static void rdtgroup_free(struct rdtgroup *rdtgroup)
> +{
> +       kfree(rdtgroup);
> +}

Any reason why you defined the above two functions?  Why not call
kzalloc() and kfree() directly?

--
Nilay