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From:   Andy Shevchenko <andy.shevchenko@gmail.com>
Date:   Sun, 6 Jun 2021 23:31:29 +0300
Message-ID: <CAHp75VdM0aziN4zHaf6=z6D0Nb=+GTbjV1pdTpRZ=yxGDZRkhw@mail.gmail.com>
Subject: Re: [PATCH v10] mm: slub: move sysfs slab alloc/free interfaces to debugfs
To:     Faiyaz Mohammed <faiyazm@codeaurora.org>
Cc:     Christoph Lameter <cl@linux.com>,
        Pekka Enberg <penberg@kernel.org>,
        David Rientjes <rientjes@google.com>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Vlastimil Babka <vbabka@suse.cz>,
        linux-mm <linux-mm@kvack.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Greg KH <greg@kroah.com>, glittao@gmail.com,
        vinmenon@codeaurora.org
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On Sun, Jun 6, 2021 at 7:16 PM Faiyaz Mohammed <faiyazm@codeaurora.org> wrote:
>
> alloc_calls and free_calls implementation in sysfs have two issues,
> one is PAGE_SIZE limitiation of sysfs and other is it does not adhere

limitation

> to "one value per file" rule.
>
> To overcome this issues, move the alloc_calls and free_calls implemeation

implementation

> to debugfs.
>
> Debugfs cache will be created if SLAB_STORE_USER flag is set.
>
> Rename the alloc_calls/free_calls to alloc_traces/free_traces,
> to be inline with what it does.

...

> +#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_SLUB_DEBUG)
> +void debugfs_slab_release(struct kmem_cache *);
> +#else

> +static inline void debugfs_slab_release(struct kmem_cache *s)
> +{
> +}

It can be one line.

> +#endif

...


> +               if (l->sum_time != l->min_time) {
> +                       seq_printf(seq, " age=%ld/%ld/%ld",
> +                               l->min_time,

> +                               (long)div_u64(l->sum_time, l->count),

Hmm... Why is the cast needed here?

> +                               l->max_time);
> +               } else
> +                       seq_printf(seq, " age=%ld",
> +                               l->min_time);

...

> +               if (num_online_cpus() > 1 &&
> +                               !cpumask_empty(to_cpumask(l->cpus)))

One line?

...

> +static const struct seq_operations slab_debugfs_sops = {
> +       .start  = slab_debugfs_start,
> +       .next   = slab_debugfs_next,
> +       .stop   = slab_debugfs_stop,

> +       .show   = slab_debugfs_show

Leave a comma here. It might not be the last one in the future.

> +};

+ blank line?

> +static int slab_debug_trace_open(struct inode *inode, struct file *filep)
> +{

...

> +static const struct file_operations slab_debugfs_fops = {
> +       .open    = slab_debug_trace_open,
> +       .read    = seq_read,
> +       .llseek  = seq_lseek,
> +       .release = slab_debug_trace_release,
> +};
> +
> +

One blank line is enough.

...

> +       debugfs_remove_recursive(debugfs_lookup(s->name,
> +                                       slab_debugfs_root));

One line?

-- 
With Best Regards,
Andy Shevchenko