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From:   Joonsoo Kim <js1304@gmail.com>
Date:   Tue, 7 Apr 2020 09:42:54 +0900
Message-ID: <CAAmzW4NxHW5boy6OiPcwzamwrJGXnEVNgn27ACtfDCoqQ3F24w@mail.gmail.com>
Subject: Re: [PATCH v5 05/10] mm/swap: charge the page when adding to the swap cache
To:     Hillf Danton <hdanton@sina.com>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Linux Memory Management List <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Michal Hocko <mhocko@kernel.org>,
        Hugh Dickins <hughd@google.com>,
        Minchan Kim <minchan@kernel.org>,
        Vlastimil Babka <vbabka@suse.cz>,
        Mel Gorman <mgorman@techsingularity.net>
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2020=EB=85=84 4=EC=9B=94 6=EC=9D=BC (=EC=9B=94) =EC=98=A4=ED=9B=84 8:58, Hi=
llf Danton <hdanton@sina.com>=EB=8B=98=EC=9D=B4 =EC=9E=91=EC=84=B1:
>
>
> On Fri,  3 Apr 2020 14:40:43 +0900 Joonsoo Kim wrote:
> >
> > @@ -153,11 +165,16 @@ int add_to_swap_cache(struct page *page, swp_entr=
y_t entry,
> >               xas_unlock_irq(&xas);
> >       } while (xas_nomem(&xas, gfp));
> >
> > -     if (!xas_error(&xas))
> > +     if (!xas_error(&xas)) {
> > +             mem_cgroup_commit_charge(page, memcg, false, compound);
>
> Add a tp
>                 trace_mm_add_to_swap_cache(page);

Please let me know the reason of this comment. IMO, adding a tracepoint isn=
't
good idea until it is really necessary since it is considered as
kernel ABI and it
cannot be changed easily.

Thanks.