From: Christian Brauner <christian.brauner@ubuntu.com> To: Minchan Kim <minchan@kernel.org> Cc: Kirill Tkhai <ktkhai@virtuozzo.com>, Michal Hocko <mhocko@suse.com>, Andrew Morton <akpm@linux-foundation.org>, LKML <linux-kernel@vger.kernel.org>, linux-mm <linux-mm@kvack.org>, linux-api@vger.kernel.org, oleksandr@redhat.com, Suren Baghdasaryan <surenb@google.com>, Tim Murray <timmurray@google.com>, Daniel Colascione <dancol@google.com>, Sandeep Patil <sspatil@google.com>, Sonny Rao <sonnyrao@google.com>, Brian Geffon <bgeffon@google.com>, Johannes Weiner <hannes@cmpxchg.org>, Shakeel Butt <shakeelb@google.com>, John Dias <joaodias@google.com> Subject: Re: [PATCH 2/4] mm: introduce external memory hinting API Date: Tue, 14 Jan 2020 20:22:50 +0100 [thread overview] Message-ID: <20200114192249.saweb3xxiex5h4ys@wittgenstein> (raw) In-Reply-To: <20200114185944.GA178589@google.com> On Tue, Jan 14, 2020 at 10:59:44AM -0800, Minchan Kim wrote: > Hi Christian, > > On Mon, Jan 13, 2020 at 08:10:47PM +0100, Christian Brauner wrote: > > On Mon, Jan 13, 2020 at 10:44:08AM -0800, Minchan Kim wrote: > > > On Mon, Jan 13, 2020 at 11:42:57AM +0100, Christian Brauner wrote: > > > > On Mon, Jan 13, 2020 at 11:47:11AM +0300, Kirill Tkhai wrote: > > > > > > < snip > > > > > > > > > > +SYSCALL_DEFINE5(process_madvise, int, pidfd, unsigned long, start, > > > > > > + size_t, len_in, int, behavior, unsigned long, flags) > > > > > > > > > > I don't like the interface. The fact we have pidfd does not mean, > > > > > we have to use it for new syscalls always. A user may want to set > > > > > madvise for specific pid from console and pass pid as argument. > > > > > pidfd would be an overkill in this case. > > > > > We usually call "kill -9 pid" from console. Why shouldn't process_madvise() > > > > > allow this? > > > > > > > > > > I suggent to extend first argument to work with both pid and pidfd. > > > > > Look at what we have for waitid(idtype, id_t id, ...) for example: > > > > > > > > > > idtype == P_PID > > > > > Wait for the child whose process ID matches id. > > > > > > > > > > idtype == P_PIDFD (since Linux 5.4) > > > > > Wait for the child referred to by the PID file descriptor specified in id. (See pidfd_open(2) for further information on > > > > > PID file descriptors.) > > > > > > > > > > We may use @flags argument for this. > > > > > > > > Sorry for chiming in just a comment. Overall, I don't particularly care > > > > how or if you integrate pidfd here. One thing I would like to point out > > > > is that we're working on a patch to place new features under pidfd > > > > specific flags. This e.g. means a pidfd would be only be able to be used > > > > for madvise operations (or getfd operations) if it was created with that > > > > specific flag set making it easier to share them with other processes. > > > > So if you integrate them here I would be quite thankful if you target > > > > the patchset for the v5.7 merge window, not for v5.6. > > > > > > Hi Christian, > > > Sorry but I couldn't understand your point. > > > Could you clarify what you meant? > > > > Hi Minchan, > > > > Sure. When you create a pidfd, e.g. with clone3() and you'd wanted to > > use it for madvise you'd need to set a flag like pidfd_cap_madvise or > > pidfd_feature_madvise when you create the pidfd. Only if the pidfd was > > created with that flag set could you use it with madvise (This does not > > affect the permission checking you're performing here.). This has come > > up a couple of times and becomes more relevant now that people keep > > adding new features on top of pidfd and is similar to what we are now > > doing with openat2(). > > Thanks for the explain. When I read discussion with you and Daniel, it's > still vague for me that what's the outcome so that it could land onto > v5.6.(If I miss something progress on other thread, sorry about that.) I'll try to post patches soon. > > I will keep Ccing you so that you may notice when this patchset could > be merged(Please Cc me when you send your patchset for me to notice) > So if we judge it's worth to integrate, maybe we could make a quick > patch to use it or postpone a cycle to intergrate it if we have more > time. Yeah, that would be great! It's unlikely that process_madvise() will land for v5.6 anyway since it's quite late in the cycle, so we should have some time to coordinate. Thanks! Christian
WARNING: multiple messages have this Message-ID (diff)
From: Christian Brauner <christian.brauner-GeWIH/nMZzLQT0dZR+AlfA@public.gmane.org> To: Minchan Kim <minchan-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> Cc: Kirill Tkhai <ktkhai-5HdwGun5lf+gSpxsJD1C4w@public.gmane.org>, Michal Hocko <mhocko-IBi9RG/b67k@public.gmane.org>, Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>, LKML <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, linux-mm <linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org>, linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, oleksandr-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, Suren Baghdasaryan <surenb-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>, Tim Murray <timmurray-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>, Daniel Colascione <dancol-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>, Sandeep Patil <sspatil-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>, Sonny Rao <sonnyrao-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>, Brian Geffon <bgeffon-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>, Johannes Weiner <hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>, Shakeel Butt <shakeelb-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>, John Dias <joaodias-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org> Subject: Re: [PATCH 2/4] mm: introduce external memory hinting API Date: Tue, 14 Jan 2020 20:22:50 +0100 [thread overview] Message-ID: <20200114192249.saweb3xxiex5h4ys@wittgenstein> (raw) In-Reply-To: <20200114185944.GA178589-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org> On Tue, Jan 14, 2020 at 10:59:44AM -0800, Minchan Kim wrote: > Hi Christian, > > On Mon, Jan 13, 2020 at 08:10:47PM +0100, Christian Brauner wrote: > > On Mon, Jan 13, 2020 at 10:44:08AM -0800, Minchan Kim wrote: > > > On Mon, Jan 13, 2020 at 11:42:57AM +0100, Christian Brauner wrote: > > > > On Mon, Jan 13, 2020 at 11:47:11AM +0300, Kirill Tkhai wrote: > > > > > > < snip > > > > > > > > > > +SYSCALL_DEFINE5(process_madvise, int, pidfd, unsigned long, start, > > > > > > + size_t, len_in, int, behavior, unsigned long, flags) > > > > > > > > > > I don't like the interface. The fact we have pidfd does not mean, > > > > > we have to use it for new syscalls always. A user may want to set > > > > > madvise for specific pid from console and pass pid as argument. > > > > > pidfd would be an overkill in this case. > > > > > We usually call "kill -9 pid" from console. Why shouldn't process_madvise() > > > > > allow this? > > > > > > > > > > I suggent to extend first argument to work with both pid and pidfd. > > > > > Look at what we have for waitid(idtype, id_t id, ...) for example: > > > > > > > > > > idtype == P_PID > > > > > Wait for the child whose process ID matches id. > > > > > > > > > > idtype == P_PIDFD (since Linux 5.4) > > > > > Wait for the child referred to by the PID file descriptor specified in id. (See pidfd_open(2) for further information on > > > > > PID file descriptors.) > > > > > > > > > > We may use @flags argument for this. > > > > > > > > Sorry for chiming in just a comment. Overall, I don't particularly care > > > > how or if you integrate pidfd here. One thing I would like to point out > > > > is that we're working on a patch to place new features under pidfd > > > > specific flags. This e.g. means a pidfd would be only be able to be used > > > > for madvise operations (or getfd operations) if it was created with that > > > > specific flag set making it easier to share them with other processes. > > > > So if you integrate them here I would be quite thankful if you target > > > > the patchset for the v5.7 merge window, not for v5.6. > > > > > > Hi Christian, > > > Sorry but I couldn't understand your point. > > > Could you clarify what you meant? > > > > Hi Minchan, > > > > Sure. When you create a pidfd, e.g. with clone3() and you'd wanted to > > use it for madvise you'd need to set a flag like pidfd_cap_madvise or > > pidfd_feature_madvise when you create the pidfd. Only if the pidfd was > > created with that flag set could you use it with madvise (This does not > > affect the permission checking you're performing here.). This has come > > up a couple of times and becomes more relevant now that people keep > > adding new features on top of pidfd and is similar to what we are now > > doing with openat2(). > > Thanks for the explain. When I read discussion with you and Daniel, it's > still vague for me that what's the outcome so that it could land onto > v5.6.(If I miss something progress on other thread, sorry about that.) I'll try to post patches soon. > > I will keep Ccing you so that you may notice when this patchset could > be merged(Please Cc me when you send your patchset for me to notice) > So if we judge it's worth to integrate, maybe we could make a quick > patch to use it or postpone a cycle to intergrate it if we have more > time. Yeah, that would be great! It's unlikely that process_madvise() will land for v5.6 anyway since it's quite late in the cycle, so we should have some time to coordinate. Thanks! Christian
next prev parent reply other threads:[~2020-01-14 19:22 UTC|newest] Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-01-10 21:34 [PATCH 0/4] introduce memory hinting API for external process Minchan Kim 2020-01-10 21:34 ` [PATCH 1/4] mm: factor out madvise's core functionality Minchan Kim 2020-01-11 7:37 ` SeongJae Park 2020-01-11 7:37 ` SeongJae Park 2020-01-13 18:11 ` Minchan Kim 2020-01-13 18:22 ` SeongJae Park 2020-01-10 21:34 ` [PATCH 2/4] mm: introduce external memory hinting API Minchan Kim 2020-01-11 7:34 ` SeongJae Park 2020-01-11 7:34 ` SeongJae Park 2020-01-13 18:02 ` Minchan Kim 2020-01-13 8:47 ` Kirill Tkhai 2020-01-13 8:47 ` Kirill Tkhai 2020-01-13 10:42 ` Christian Brauner 2020-01-13 10:42 ` Christian Brauner 2020-01-13 18:44 ` Minchan Kim 2020-01-13 18:44 ` Minchan Kim 2020-01-13 19:10 ` Christian Brauner 2020-01-13 19:27 ` Daniel Colascione 2020-01-13 19:27 ` Daniel Colascione 2020-01-13 19:27 ` Daniel Colascione 2020-01-13 20:42 ` Christian Brauner 2020-01-13 21:04 ` Daniel Colascione 2020-01-13 21:04 ` Daniel Colascione 2020-01-13 21:04 ` Daniel Colascione 2020-01-14 19:20 ` Christian Brauner 2020-01-14 18:59 ` Minchan Kim 2020-01-14 18:59 ` Minchan Kim 2020-01-14 19:22 ` Christian Brauner [this message] 2020-01-14 19:22 ` Christian Brauner 2020-01-13 18:39 ` Minchan Kim 2020-01-13 19:18 ` Daniel Colascione 2020-01-13 19:18 ` Daniel Colascione 2020-01-13 19:18 ` Daniel Colascione 2020-01-14 8:39 ` Kirill Tkhai 2020-01-14 8:39 ` Kirill Tkhai 2020-01-14 19:12 ` Minchan Kim 2020-01-15 9:38 ` Kirill Tkhai 2020-01-10 21:34 ` [PATCH 3/4] mm/madvise: employ mmget_still_valid for write lock Minchan Kim 2020-01-10 21:34 ` [PATCH 4/4] mm/madvise: allow KSM hints for remote API Minchan Kim 2020-01-10 21:34 ` Minchan Kim 2020-01-11 7:42 ` SeongJae Park
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20200114192249.saweb3xxiex5h4ys@wittgenstein \ --to=christian.brauner@ubuntu.com \ --cc=akpm@linux-foundation.org \ --cc=bgeffon@google.com \ --cc=dancol@google.com \ --cc=hannes@cmpxchg.org \ --cc=joaodias@google.com \ --cc=ktkhai@virtuozzo.com \ --cc=linux-api@vger.kernel.org \ --cc=linux-kernel@vger.kernel.org \ --cc=linux-mm@kvack.org \ --cc=mhocko@suse.com \ --cc=minchan@kernel.org \ --cc=oleksandr@redhat.com \ --cc=shakeelb@google.com \ --cc=sonnyrao@google.com \ --cc=sspatil@google.com \ --cc=surenb@google.com \ --cc=timmurray@google.com \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.