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Date:   Mon, 23 Mar 2020 10:49:46 +0100
From:   Greg KH <gregkh@linuxfoundation.org>
To:     Jaewon Kim <jaewon31.kim@samsung.com>
Cc:     leon@kernel.org, vbabka@suse.cz, adobriyan@gmail.com,
        akpm@linux-foundation.org, labbott@redhat.com,
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        sergey.senozhatsky.work@gmail.com, kasong@redhat.com,
        bhe@redhat.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        jaewon31.kim@gmail.com, linux-api@vger.kernel.org,
        kexec@lists.infradead.org
Subject: Re: [RFC PATCH v2 3/3] android: ion: include system heap size in
 meminfo extra
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On Mon, Mar 23, 2020 at 05:05:03PM +0900, Jaewon Kim wrote:
> In Android system ion system heap size is huge like hundreds of MB. To
> know overal system memory usage, include ion system heap size in
> proc/meminfo_extra.
> 
> To include heap size, use register_meminfo_extra introduced in previous
> patch.
> 
> Prior to register we need to add stats to show the ion heap usage. Add
> total_allocated into ion heap and count it on allocation and freeing. In
> a ion heap using ION_HEAP_FLAG_DEFER_FREE, a buffer can be freed from
> user but still live on deferred free list. Keep stats until the buffer
> is finally freed so that we can cover situation of deferred free thread
> stuck problem.
> 
> i.e) cat /proc/meminfo_extra | grep IonSystemHeap
> IonSystemHeap:    242620 kB
> 
> i.e.) show_mem on oom
> <6>[  420.856428]  Mem-Info:
> <6>[  420.856433]  IonSystemHeap:32813kB
> 
> Signed-off-by: Jaewon Kim <jaewon31.kim@samsung.com>
> ---
>  drivers/staging/android/ion/ion.c             | 2 ++
>  drivers/staging/android/ion/ion.h             | 1 +
>  drivers/staging/android/ion/ion_system_heap.c | 2 ++
>  3 files changed, 5 insertions(+)

Does this really give the proper granularity that ion users have?  I
thought they wanted to know what each heap was doing.

Also, this code should be deleted really soon now, so I would not make
any core changes to the kernel based on it at all.

thanks,

greg k-h