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From:   Daniel Colascione <dancol@google.com>
Date:   Wed, 22 May 2019 08:17:23 -0700
Message-ID: <CAKOZueu837QGDAGat-tdA9J1qtKaeuQ5rg0tDyEjyvd_hjVc6g@mail.gmail.com>
Subject: Re: [RFC 0/7] introduce memory hinting API for external process
To:     Christian Brauner <christian@brauner.io>
Cc:     Minchan Kim <minchan@kernel.org>,
        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>,
        Shakeel Butt <shakeelb@google.com>,
        Sonny Rao <sonnyrao@google.com>,
        Brian Geffon <bgeffon@google.com>, Jann Horn <jannh@google.com>
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On Wed, May 22, 2019 at 7:52 AM Christian Brauner <christian@brauner.io> wrote:
> I'm not going to go into yet another long argument. I prefer pidfd_*.

Ok. We're each allowed our opinion.

> It's tied to the api, transparent for userspace, and disambiguates it
> from process_vm_{read,write}v that both take a pid_t.

Speaking of process_vm_readv and process_vm_writev: both have a
currently-unused flags argument. Both should grow a flag that tells
them to interpret the pid argument as a pidfd. Or do you support
adding pidfd_vm_readv and pidfd_vm_writev system calls? If not, why
should process_madvise be called pidfd_madvise while process_vm_readv
isn't called pidfd_vm_readv?