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Date:   Wed, 22 Jan 2020 17:43:16 -0800
From:   Minchan Kim <minchan@kernel.org>
To:     Oleksandr Natalenko <oleksandr@redhat.com>
Cc:     "Kirill A. Shutemov" <kirill@shutemov.name>,
        Michal Hocko <mhocko@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        LKML <linux-kernel@vger.kernel.org>,
        linux-mm <linux-mm@kvack.org>, linux-api@vger.kernel.org,
        Suren Baghdasaryan <surenb@google.com>,
        Tim Murray <timmurray@google.com>,
        Daniel Colascione <dancol@google.com>,
        Sandeep Patil <sspatil@google.com>,
        Sonny Rao <sonnyrao@google.com>,
        Brian Geffon <bgeffon@google.com>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Shakeel Butt <shakeelb@google.com>,
        John Dias <joaodias@google.com>, ktkhai@virtuozzo.com,
        christian.brauner@ubuntu.com, sjpark@amazon.de
Subject: Re: [PATCH v2 2/5] mm: introduce external memory hinting API
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On Wed, Jan 22, 2020 at 11:44:24AM +0100, Oleksandr Natalenko wrote:
> Hello.
> 
> On Tue, Jan 21, 2020 at 10:11:13AM -0800, Minchan Kim wrote:
> > > > I also think people don't want to give an KSM hint to non-mergeable area.
> > > 
> > > And how the manager knows which data is mergable?
> > 
> > Oleksandr, could you say your thought why you need address range based
> > API?
> 
> It seems I've overlooked an important piece of this submission: one
> cannot apply the hint to all the anonymous mapping regardless of address
> range. For KSM I'd rather either have a possibility to hint all the
> anonymous mappings, or, as it was suggested previously, be able to iterate
> over existing mappings using some (fd-based?) API.

Thing is how you could identify a certan range is better for KSM than
others from external process?