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From:   Andy Lutomirski <luto@kernel.org>
Date:   Wed, 30 Jun 2021 17:44:36 -0700
Message-ID: <CALCETrWsVw4+jT_Z1uxidRAZ0SQbngYe7E2m-8iyX6qRbug6zA@mail.gmail.com>
Subject: Re: [PATCH 1/1] mm: introduce process_reap system call
To:     Johannes Weiner <hannes@cmpxchg.org>
Cc:     Suren Baghdasaryan <surenb@google.com>,
        Andy Lutomirski <luto@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Michal Hocko <mhocko@kernel.org>,
        Michal Hocko <mhocko@suse.com>,
        David Rientjes <rientjes@google.com>,
        Matthew Wilcox <willy@infradead.org>,
        Roman Gushchin <guro@fb.com>, Rik van Riel <riel@surriel.com>,
        Minchan Kim <minchan@kernel.org>,
        Christian Brauner <christian@brauner.io>,
        Christoph Hellwig <hch@infradead.org>,
        Oleg Nesterov <oleg@redhat.com>,
        David Hildenbrand <david@redhat.com>,
        Jann Horn <jannh@google.com>,
        Shakeel Butt <shakeelb@google.com>,
        Tim Murray <timmurray@google.com>,
        Linux API <linux-api@vger.kernel.org>,
        Linux-MM <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Android Kernel Team <kernel-team@android.com>
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On Wed, Jun 30, 2021 at 2:45 PM Johannes Weiner <hannes@cmpxchg.org> wrote:
>
> On Wed, Jun 30, 2021 at 11:51:36AM -0700, Suren Baghdasaryan wrote:
> > On Wed, Jun 30, 2021 at 11:26 AM Andy Lutomirski <luto@kernel.org> wrote:
> > > Also, please consider removing all mention of the word "reap" from the
> > > user API.  For better or for worse, "reap" in UNIX refers to what
> > > happens when a dead task gets wait()ed.  I sincerely wish I could go
> > > back in time and gently encourage whomever invented that particular
> > > abomination to change their mind, but my time machine doesn't work.
> >
> > I see. Thanks for the note. How about process_mem_release() and
> > replacing reap with release everywhere?
>
> I don't quite understand the objection. This syscall works on tasks
> that are at the end of their life, right? Isn't something like
> process_mreap() establishing exactly the mental link we want here?
> Release is less descriptive for what this thing is to be used for.

For better or for worse, "reap" means to make a zombie pid go away.
From the description, this new operation takes a dying process (not
necessarily a zombie yet) and aggressively frees its memory.  This is
a different optioneration.

How about "free_dying_process_memory"?