From: Minchan Kim <minchan@kernel.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Alexander Duyck <alexander.h.duyck@linux.intel.com>,
Jens Axboe <axboe@kernel.dk>, Brian Geffon <bgeffon@google.com>,
Christian Brauner <christian.brauner@ubuntu.com>,
Christian Brauner <christian@brauner.io>,
Daniel Colascione <dancol@google.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Jann Horn <jannh@google.com>, John Dias <joaodias@google.com>,
Joel Fernandes <joel@joelfernandes.org>,
Kirill Tkhai <ktkhai@virtuozzo.com>,
linux-man <linux-man@vger.kernel.org>,
Linux-MM <linux-mm@kvack.org>, Michal Hocko <mhocko@suse.com>,
mm-commits@vger.kernel.org,
Oleksandr Natalenko <oleksandr@redhat.com>,
David Rientjes <rientjes@google.com>,
Shakeel Butt <shakeelb@google.com>,
sj38.park@gmail.com, sjpark@amazon.de,
Sonny Rao <sonnyrao@google.com>,
Sandeep Patil <sspatil@google.com>,
Suren Baghdasaryan <surenb@google.com>,
Tim Murray <timmurray@google.com>,
Vlastimil Babka <vbabka@suse.cz>
Subject: Re: [patch 18/39] mm/madvise: check fatal signal pending of target process
Date: Fri, 14 Aug 2020 21:59:00 -0700 [thread overview]
Message-ID: <20200815045900.GA2936603@google.com> (raw)
In-Reply-To: <CAHk-=wgZ6ZgRWRm0rGgLkYR-_XwKeuWxwbkBWxmCOzt7dGxWpg@mail.gmail.com>
On Fri, Aug 14, 2020 at 07:53:09PM -0700, Linus Torvalds wrote:
> On Fri, Aug 14, 2020 at 5:31 PM Andrew Morton <akpm@linux-foundation.org> wrote:
> >
> > From: Minchan Kim <minchan@kernel.org>
> > Subject: mm/madvise: check fatal signal pending of target process
> >
> > Bail out to prevent unnecessary CPU overhead if target process has pending
> > fatal signal during (MADV_COLD|MADV_PAGEOUT) operation.
>
> This seems bogus.
>
> Returning -EINTR when *SOMEBODY ELSE* has a signal is crazy talk.
It doesn't propagate -EINTR to the user but just aiming for canceling
the entire operation.
>
> It also seems to be the reason for the previous patches inexplicably
> passing in the task pointer.
>
> Finally, it has absolutely no explanations for why this would matter,
> and why it's magically and suddenly an issue for process_madvise(),
> when in the history of the *real* madvise() this hasn't been an issue
> for "current".
Currently, madvise(MADV_COLD|PAGEOUT) already have done it. I just wanted
to sync with it with process_madvise. Ting was process_madvise couldn't
get target task while madvise could get it easily.
>
> I'm dropping the madvise() series.
>
> If the issue is that you can generate a long series or areas with that
> iovec, maybe the code should re-consider. Or maybe the signal pending
> case should be done there, not passing down an odd task pointer to the
> low-level madvise code.
Do you mean you want to drop target signal check madvise as well as
process_madvise?
next prev parent reply other threads:[~2020-08-15 22:04 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20200814172939.55d6d80b6e21e4241f1ee1f3@linux-foundation.org>
2020-08-15 0:30 ` [patch 15/39] mm/madvise: pass task and mm to do_madvise Andrew Morton
2020-08-15 0:30 ` [patch 16/39] pid: move pidfd_get_pid() to pid.c Andrew Morton
2020-08-15 0:30 ` [patch 17/39] mm/madvise: introduce process_madvise() syscall: an external memory hinting API Andrew Morton
2020-08-16 8:12 ` Christian Brauner
2020-08-17 15:10 ` Minchan Kim
2020-08-15 0:31 ` [patch 18/39] mm/madvise: check fatal signal pending of target process Andrew Morton
2020-08-15 2:53 ` Linus Torvalds
2020-08-15 4:59 ` Minchan Kim [this message]
2020-08-15 14:57 ` Linus Torvalds
2020-08-15 18:34 ` Minchan Kim
2020-08-16 1:43 ` Linus Torvalds
2020-08-16 5:58 ` Minchan Kim
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