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Subject: Re: [RFC PATCH 3/4] mm: add sys fs configuration for page reporting
To:     Mel Gorman <mgorman@techsingularity.net>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org,
        Andrea Arcangeli <aarcange@redhat.com>,
        Dan Williams <dan.j.williams@intel.com>,
        Dave Hansen <dave.hansen@intel.com>,
        David Hildenbrand <david@redhat.com>,
        Michal Hocko <mhocko@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Alex Williamson <alex.williamson@redhat.com>
References: <20200412090919.GA19580@open-light-1.localdomain>
From:   Alexander Duyck <alexander.h.duyck@linux.intel.com>
Message-ID: <64985d09-d11e-5fc0-64b0-b56ef514448a@linux.intel.com>
Date:   Mon, 13 Apr 2020 08:02:35 -0700
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On 4/12/2020 2:09 AM, liliangleo wrote:
> This patch add 'delay_millisecs', 'mini_order', 'batch_size',
> in '/sys/kernel/mm/page_report/'. Usage:
> 
> "delay_millisecs":
> Time delay interval between page free and work start to run.
> 
> "mini_order":
> Only pages with order equal or greater than mini_order will be
> reported.
> 
> "batch_size"
> Wake up the worker only when free pages total size are greater
> than 'batch_size'.
> 
> Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com>
> Cc: Mel Gorman <mgorman@techsingularity.net>
> Cc: Andrea Arcangeli <aarcange@redhat.com>
> Cc: Dan Williams <dan.j.williams@intel.com>
> Cc: Dave Hansen <dave.hansen@intel.com>
> Cc: David Hildenbrand <david@redhat.com>
> Cc: Michal Hocko <mhocko@kernel.org>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Alex Williamson <alex.williamson@redhat.com>
> Signed-off-by: liliangleo <liliangleo@didiglobal.com>

I am not really a fan of making these configurable globally. Especially 
since the existing virtio-balloon is relying on some of this being 
configured the way it is.

It would make much more sense to push these configuration options out to 
the registration interface so that the thing that is registering for 
page reporting can configure them when it is registered.