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Thu, 8 Jul 2021 05:41:14 +0000 (UTC) Received: from oldenburg.str.redhat.com (ovpn-115-5.ams2.redhat.com [10.36.115.5]) by smtp.corp.redhat.com (Postfix) with ESMTPS id AB8CD5D9DD; Thu, 8 Jul 2021 05:41:00 +0000 (UTC) From: Florian Weimer To: Suren Baghdasaryan Cc: Andrew Morton , Michal Hocko , Michal Hocko , David Rientjes , Matthew Wilcox , Johannes Weiner , Roman Gushchin , Rik van Riel , Minchan Kim , Christian Brauner , Christoph Hellwig , Oleg Nesterov , David Hildenbrand , Jann Horn , Shakeel Butt , Tim Murray , Linux API , linux-mm , LKML , kernel-team Subject: Re: [PATCH 1/1] mm: introduce process_reap system call References: <20210623192822.3072029-1-surenb@google.com> <87sg0qa22l.fsf@oldenburg.str.redhat.com> Date: Thu, 08 Jul 2021 07:40:58 +0200 In-Reply-To: (Suren Baghdasaryan's message of "Wed, 7 Jul 2021 14:07:15 -0700") Message-ID: <87wnq1z7kl.fsf@oldenburg.str.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Stat-Signature: pgzhj69wq3ictq53k7aro4fnrowsabhr X-Rspamd-Queue-Id: B257A7000081 X-Rspamd-Server: rspam01 X-Rspam-User: nil Authentication-Results: imf27.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=DyWeTCs9; dmarc=pass (policy=none) header.from=redhat.com; spf=none (imf27.hostedemail.com: domain of fweimer@redhat.com has no SPF policy when checking 216.205.24.124) smtp.mailfrom=fweimer@redhat.com X-HE-Tag: 1625722881-716088 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: * Suren Baghdasaryan: > On Wed, Jul 7, 2021 at 2:47 AM Florian Weimer wrote: >> >> * Suren Baghdasaryan: >> >> > The API is as follows, >> > >> > int process_reap(int pidfd, unsigned int flags); >> > >> > DESCRIPTION >> > The process_reap() system call is used to free the memory of= a >> > dying process. >> > >> > The pidfd selects the process referred to by the PID file >> > descriptor. >> > (See pidofd_open(2) for further information) >> > >> > The flags argument is reserved for future use; currently, th= is >> > argument must be specified as 0. >> > >> > RETURN VALUE >> > On success, process_reap() returns 0. On error, -1 is return= ed >> > and errno is set to indicate the error. >> >> I think the manual page should mention what it means for a process to be >> =E2=80=9Cdying=E2=80=9D, and how to move a process to this state. > > Thanks for the suggestion, Florian! Would replacing "dying process" > with "process which was sent a SIGKILL signal" be sufficient? That explains very clearly the requirement, but it raises the question why this isn't an si_code flag for rt_sigqueueinfo, reusing the existing system call. Thanks, Florian