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Date:   Thu, 16 May 2019 09:53:11 +0200
From:   Greg KH <greg@kroah.com>
To:     Michal Hocko <mhocko@kernel.org>
Cc:     Oleksandr Natalenko <oleksandr@redhat.com>,
        linux-kernel@vger.kernel.org, Kirill Tkhai <ktkhai@virtuozzo.com>,
        Vlastimil Babka <vbabka@suse.cz>,
        Matthew Wilcox <willy@infradead.org>,
        Pavel Tatashin <pasha.tatashin@soleen.com>,
        Timofey Titovets <nefelim4ag@gmail.com>,
        Aaron Tomlin <atomlin@redhat.com>,
        Grzegorz Halat <ghalat@redhat.com>, linux-mm@kvack.org,
        linux-api@vger.kernel.org, Hugh Dickins <hughd@google.com>,
        Suren Baghdasaryan <surenb@google.com>,
        Minchan Kim <minchan@kernel.org>
Subject: Re: [PATCH RFC v2 0/4] mm/ksm: add option to automerge VMAs
Message-ID: <20190516075311.GA10467@kroah.com>
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On Thu, May 16, 2019 at 09:47:13AM +0200, Michal Hocko wrote:
> On Wed 15-05-19 17:15:57, Greg KH wrote:
> > On Wed, May 15, 2019 at 04:51:51PM +0200, Michal Hocko wrote:
> > > [Cc Suren and Minchan - the email thread starts here 20190514131654.25463-1-oleksandr@redhat.com]
> > > 
> > > On Wed 15-05-19 08:53:11, Michal Hocko wrote:
> > > [...]
> > > > I will try to comment on the interface itself later. But I have to say
> > > > that I am not impressed. Abusing sysfs for per process features is quite
> > > > gross to be honest.
> > > 
> > > I have already commented on this in other email. I consider sysfs an
> > > unsuitable interface for per-process API.
> > 
> > Wait, what?  A new sysfs file/directory per process?  That's crazy, no
> > one must have benchmarked it :)
> 
> Just to clarify, that was not a per process file but rather per process API.
> Essentially echo $PID > $SYSFS_SPECIAL_FILE

Ick, no, that's not ok either.  sysfs files are not a replacement for
syscalls :)

thanks,

greg k-h