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Date:   Fri, 19 Mar 2021 14:47:45 +0100
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     Dmitry Osipenko <digetx@gmail.com>
Cc:     Minchan Kim <minchan@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        linux-mm <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>, joaodias@google.com,
        willy@infradead.org, david@redhat.com, surenb@google.com,
        John Hubbard <jhubbard@nvidia.com>,
        Nicolas Chauvet <kwizart@gmail.com>,
        "linux-tegra@vger.kernel.org" <linux-tegra@vger.kernel.org>
Subject: Re: [PATCH v4] mm: cma: support sysfs
Message-ID: <YFSrgfAyp+dYWi7k@kroah.com>
References: <20210309062333.3216138-1-minchan@kernel.org>
 <fead70a2-4330-79ff-e79a-d8511eab1256@gmail.com>
 <e8ae901d-9521-8de4-ee45-18cb55b8f29c@gmail.com>
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On Fri, Mar 19, 2021 at 04:45:21PM +0300, Dmitry Osipenko wrote:
> 19.03.2021 16:42, Greg Kroah-Hartman пишет:
> > On Fri, Mar 19, 2021 at 04:39:41PM +0300, Dmitry Osipenko wrote:
> >> 19.03.2021 15:44, Dmitry Osipenko пишет:
> >> ...
> >>>>  #include <linux/debugfs.h>
> >>>> +#include <linux/kobject.h>
> >>>> +
> >>>> +struct cma_stat {
> >>>> +	spinlock_t lock;
> >>>> +	/* the number of CMA page successful allocations */
> >>>> +	unsigned long nr_pages_succeeded;
> >>>> +	/* the number of CMA page allocation failures */
> >>>> +	unsigned long nr_pages_failed;
> >>>> +	struct kobject kobj;
> >>>> +};
> >>>>  
> >>>>  struct cma {
> >>>>  	unsigned long   base_pfn;
> >>>> @@ -16,6 +26,9 @@ struct cma {
> >>>>  	struct debugfs_u32_array dfs_bitmap;
> >>>>  #endif
> >>>>  	char name[CMA_MAX_NAME];
> >>>> +#ifdef CONFIG_CMA_SYSFS
> >>>> +	struct cma_stat	*stat;
> >>>> +#endif
> >>
> >> What is the point of allocating stat dynamically?
> > 
> > Because static kobjects make me cry.
> > 
> 
> I meant that it's already a part of struct cma, it looks like the stat
> could be embedded into struct cma and then kobj could be initialized
> separately.

But that structure is statically allocated, so it can not be.  This has
been discussed in the past threads for when this was reviewed if you are
curious :)

thanks,

greg k-h