From: Minchan Kim <minchan@kernel.org>
To: Alexander Duyck <alexander.duyck@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
LKML <linux-kernel@vger.kernel.org>,
linux-mm <linux-mm@kvack.org>,
Linux API <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>, Michal Hocko <mhocko@suse.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Shakeel Butt <shakeelb@google.com>,
John Dias <joaodias@google.com>,
Joel Fernandes <joel@joelfernandes.org>
Subject: Re: [PATCH v3 5/5] mm: support both pid and pidfd for process_madvise
Date: Tue, 11 Feb 2020 13:11:49 -0800 [thread overview]
Message-ID: <20200211211149.GC185752@google.com> (raw)
In-Reply-To: <CAKgT0Ue9y=CL-f8xNXLo70nSk1wR_tG6TYXQUYpfk42PkHWeug@mail.gmail.com>
On Mon, Feb 10, 2020 at 03:12:52PM -0800, Alexander Duyck wrote:
> On Mon, Jan 27, 2020 at 4:17 PM Minchan Kim <minchan@kernel.org> wrote:
> >
> > There is a demand[1] to support pid as well pidfd for process_madvise
> > to reduce unncessary syscall to get pidfd if the user has control of
> > the targer process(ie, they could gaurantee the process is not gone
> > or pid is not reused. Or, it might be okay to give a hint to wrong
> > process).
>
> It looks like you misspelled several items in here including
> "unnecessary", "target", and "guarantee".
Thanks, will fix it.
>
> > This patch aims for supporting both options like waitid(2). So, the
> > syscall is currently,
> >
> > int process_madvise(int which, pid_t pid, void *addr,
> > size_t length, int advise, unsigned long flag);
> >
> > @which is actually idtype_t for userspace libray and currently,
> > it supports P_PID and P_PIDFD.
> >
> > [1] https://lore.kernel.org/linux-mm/9d849087-3359-c4ab-fbec-859e8186c509@virtuozzo.com/
> > Signed-off-by: Minchan Kim <minchan@kernel.org>
> > ---
> > include/linux/pid.h | 1 +
> > include/linux/syscalls.h | 3 ++-
> > kernel/exit.c | 17 -----------------
> > kernel/pid.c | 17 +++++++++++++++++
> > mm/madvise.c | 34 ++++++++++++++++++++++------------
> > 5 files changed, 42 insertions(+), 30 deletions(-)
> >
> > diff --git a/include/linux/pid.h b/include/linux/pid.h
> > index 998ae7d24450..023d9c3a8edc 100644
> > --- a/include/linux/pid.h
> > +++ b/include/linux/pid.h
> > @@ -75,6 +75,7 @@ extern const struct file_operations pidfd_fops;
> > struct file;
> >
> > extern struct pid *pidfd_pid(const struct file *file);
> > +extern struct pid *pidfd_get_pid(unsigned int fd);
> >
> > static inline struct pid *get_pid(struct pid *pid)
> > {
>
> So really this is two patches interleaved. You have the moving of the
> pidfd_get_pid function and the update of the syscall. Personally I
> would make the function move a separate patch and place it before you
> define the syscall and fold the syscall changes into your original
> patch.
>
> Doing that you wouldn't have to worry about the syscall changing in
> behavior midway through a bisect. It would either be there or it
> wouldn't.
Will try it.
Thanks!
next prev parent reply other threads:[~2020-02-11 21:11 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-28 0:16 [PATCH v3 0/5] introduce memory hinting API for external process Minchan Kim
2020-01-28 0:16 ` [PATCH v3 1/5] mm: factor out madvise's core functionality Minchan Kim
2020-02-10 23:00 ` Alexander Duyck
2020-02-11 21:08 ` Minchan Kim
2020-01-28 0:16 ` [PATCH v3 2/5] mm: introduce external memory hinting API Minchan Kim
2020-02-10 17:50 ` Suren Baghdasaryan
2020-02-10 21:27 ` Minchan Kim
2020-01-28 0:16 ` [PATCH v3 3/5] mm/madvise: employ mmget_still_valid for write lock Minchan Kim
2020-01-28 0:16 ` [PATCH v3 4/5] mm/madvise: allow KSM hints for remote API Minchan Kim
2020-01-28 0:16 ` [PATCH v3 5/5] mm: support both pid and pidfd for process_madvise Minchan Kim
2020-02-10 23:12 ` Alexander Duyck
2020-02-11 21:11 ` Minchan Kim [this message]
2020-02-10 21:29 ` [PATCH v3 0/5] introduce memory hinting API for external process Minchan Kim
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=20200211211149.GC185752@google.com \
--to=minchan@kernel.org \
--cc=akpm@linux-foundation.org \
--cc=alexander.duyck@gmail.com \
--cc=bgeffon@google.com \
--cc=dancol@google.com \
--cc=hannes@cmpxchg.org \
--cc=joaodias@google.com \
--cc=joel@joelfernandes.org \
--cc=linux-api@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mhocko@suse.com \
--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: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).