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From:   Liang Li <liliang324@gmail.com>
Date:   Mon, 4 Jan 2021 21:45:17 +0800
Message-ID: <CA+2MQi9900FU9+=j7EM2YEH5=Dg0wH9-GvfZDhop6kGO_=a2Pw@mail.gmail.com>
Subject: Re: [RFC v2 PATCH 0/4] speed up page allocation for __GFP_ZERO
To:     Michal Hocko <mhocko@suse.com>
Cc:     Matthew Wilcox <willy@infradead.org>,
        Alexander Duyck <alexander.h.duyck@linux.intel.com>,
        Mel Gorman <mgorman@techsingularity.net>,
        Andrew Morton <akpm@linux-foundation.org>,
        Andrea Arcangeli <aarcange@redhat.com>,
        Dan Williams <dan.j.williams@intel.com>,
        "Michael S. Tsirkin" <mst@redhat.com>,
        David Hildenbrand <david@redhat.com>,
        Jason Wang <jasowang@redhat.com>,
        Dave Hansen <dave.hansen@intel.com>,
        Liang Li <liliangleo@didiglobal.com>,
        linux-mm <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>,
        virtualization@lists.linux-foundation.org
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> > Win or not depends on its effect. For our case, it solves the issue
> > that we faced, so it can be thought as a win for us.  If others don't
> > have the issue we faced, the result will be different, maybe they will
> > be affected by the side effect of this feature. I think this is your
> > concern behind the question. right? I will try to do more tests and
> > provide more benchmark performance data.
>
> Yes, zeroying memory does have a noticeable overhead but we cannot
> simply allow tasks to spil over this overhead to all other users by
> default. So if anything this would need to be an opt-in feature
> configurable by administrator.
> --
> Michal Hocko
> SUSE Labs

I know the overhead, so I add a switch in /sys/ to enable or disable
it dynamically.

Thanks
Liang