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Date:   Mon, 20 May 2019 18:44:52 -0700
From:   Matthew Wilcox <willy@infradead.org>
To:     Minchan Kim <minchan@kernel.org>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        LKML <linux-kernel@vger.kernel.org>,
        linux-mm <linux-mm@kvack.org>, Michal Hocko <mhocko@suse.com>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Tim Murray <timmurray@google.com>,
        Joel Fernandes <joel@joelfernandes.org>,
        Suren Baghdasaryan <surenb@google.com>,
        Daniel Colascione <dancol@google.com>,
        Shakeel Butt <shakeelb@google.com>,
        Sonny Rao <sonnyrao@google.com>,
        Brian Geffon <bgeffon@google.com>
Subject: Re: [RFC 0/7] introduce memory hinting API for external process
Message-ID: <20190521014452.GA6738@bombadil.infradead.org>
References: <20190520035254.57579-1-minchan@kernel.org>
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On Mon, May 20, 2019 at 12:52:47PM +0900, Minchan Kim wrote:
> IMHO we should spell it out that this patchset complements MADV_WONTNEED
> and MADV_FREE by adding non-destructive ways to gain some free memory
> space. MADV_COLD is similar to MADV_WONTNEED in a way that it hints the
> kernel that memory region is not currently needed and should be reclaimed
> immediately; MADV_COOL is similar to MADV_FREE in a way that it hints the
> kernel that memory region is not currently needed and should be reclaimed
> when memory pressure rises.

Do we tear down page tables for these ranges?  That seems like a good
way of reclaiming potentially a substantial amount of memory.