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Date:   Wed, 17 Oct 2018 13:09:52 +0200
From:   Michal Hocko <mhocko@kernel.org>
To:     John Hubbard <jhubbard@nvidia.com>
Cc:     Jan Kara <jack@suse.cz>, Dave Chinner <david@fromorbit.com>,
        Matthew Wilcox <willy@infradead.org>,
        Christopher Lameter <cl@linux.com>,
        Jason Gunthorpe <jgg@ziepe.ca>,
        Dan Williams <dan.j.williams@intel.com>, linux-mm@kvack.org,
        Andrew Morton <akpm@linux-foundation.org>,
        LKML <linux-kernel@vger.kernel.org>,
        linux-rdma <linux-rdma@vger.kernel.org>,
        linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 4/6] mm: introduce page->dma_pinned_flags, _count
Message-ID: <20181017110952.GN18839@dhcp22.suse.cz>
References: <20181012060014.10242-1-jhubbard@nvidia.com>
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 <20181013035516.GA18822@dastard>
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 <20181013230124.GB18822@dastard>
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On Tue 16-10-18 18:48:23, John Hubbard wrote:
[...]
> It's hard to say exactly what the active/inactive/unevictable list should
> be when DMA is done and put_user_page*() is called, because we don't know
> if some device read, wrote, or ignored any of those pages. Although if 
> put_user_pages_dirty() is called, that's an argument for "active", at least.

Any reason to not use putback_lru_page?

Please note I haven't really got through your patches to have a wider
picture of the change so this is just hint for the LRU part of the
issue.
-- 
Michal Hocko
SUSE Labs