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Date:   Thu, 18 Aug 2022 10:11:23 +0530
From:   Ritesh Harjani <ritesh.list@gmail.com>
To:     Alexander Atanasov <alexander.atanasov@virtuozzo.com>
Cc:     Michael Ellerman <mpe@ellerman.id.au>,
        Nicholas Piggin <npiggin@gmail.com>,
        Christophe Leroy <christophe.leroy@csgroup.eu>,
        Nadav Amit <namit@vmware.com>,
        VMware PV-Drivers Reviewers <pv-drivers@vmware.com>,
        Arnd Bergmann <arnd@arndb.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "Michael S. Tsirkin" <mst@redhat.com>,
        David Hildenbrand <david@redhat.com>,
        Jason Wang <jasowang@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>, kernel@openvz.org,
        linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
        virtualization@lists.linux-foundation.org, linux-mm@kvack.org
Subject: Re: [PATCH v2 1/4] Make place for common balloon code
Message-ID: <20220818044123.q5yzdaszcxl7mcl6@riteshh-domain>
References: <20220816094117.3144881-1-alexander.atanasov@virtuozzo.com>
 <20220816094117.3144881-2-alexander.atanasov@virtuozzo.com>
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On 22/08/16 12:41PM, Alexander Atanasov wrote:
> File already contains code that is common along balloon
> drivers so rename it to reflect its contents.
> mm/balloon_compaction.c -> mm/balloon_common.c
>
> Signed-off-by: Alexander Atanasov <alexander.atanasov@virtuozzo.com>
> ---
>  MAINTAINERS                                              | 4 ++--
>  arch/powerpc/platforms/pseries/cmm.c                     | 2 +-
>  drivers/misc/vmw_balloon.c                               | 2 +-
>  drivers/virtio/virtio_balloon.c                          | 2 +-
>  include/linux/{balloon_compaction.h => balloon_common.h} | 2 +-
>  mm/Makefile                                              | 2 +-
>  mm/{balloon_compaction.c => balloon_common.c}            | 4 ++--

>  mm/migrate.c                                             | 2 +-
>  mm/vmscan.c                                              | 2 +-
I think we don't need balloon headers in above two files at all.
I don't see any references of balloon functions in them.

I guess this commit removed it -

commit b1123ea6d3b3da25af5c8a9d843bd07ab63213f4
Author: Minchan Kim <minchan@kernel.org>
Date:   Tue Jul 26 15:23:09 2016 -0700

    mm: balloon: use general non-lru movable page feature

    Now, VM has a feature to migrate non-lru movable pages so balloon
    doesn't need custom migration hooks in migrate.c and compaction.c.

    Instead, this patch implements the page->mapping->a_ops->
    {isolate|migrate|putback} functions.

    With that, we could remove hooks for ballooning in general migration
    functions and make balloon compaction simple.

Since I don't often look into this side of code, it's better to confirm :)

-ritesh