From: Suren Baghdasaryan <surenb@google.com>
To: David Hildenbrand <david@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>,
Shakeel Butt <shakeelb@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
David Rientjes <rientjes@google.com>,
Matthew Wilcox <willy@infradead.org>,
Johannes Weiner <hannes@cmpxchg.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>, Jann Horn <jannh@google.com>,
Andy Lutomirski <luto@kernel.org>,
Christian Brauner <christian.brauner@ubuntu.com>,
Florian Weimer <fweimer@redhat.com>,
Jan Engelhardt <jengelh@inai.de>,
Tim Murray <timmurray@google.com>,
Linux API <linux-api@vger.kernel.org>,
Linux MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
kernel-team <kernel-team@android.com>
Subject: Re: [PATCH v3 1/2] mm: introduce process_mrelease system call
Date: Fri, 23 Jul 2021 01:18:56 -0700 [thread overview]
Message-ID: <CAJuCfpFSi2eLQL1YkHOubX+53Aa1ngZ1hS2+QervFnt5dLEQSw@mail.gmail.com> (raw)
In-Reply-To: <23ed1d8d-fe55-fdbc-ca33-01a3ce392dff@redhat.com>
On Fri, Jul 23, 2021 at 1:15 AM David Hildenbrand <david@redhat.com> wrote:
>
> On 23.07.21 10:11, Suren Baghdasaryan wrote:
> >
> >
> > On Thu, Jul 22, 2021, 11:20 PM Michal Hocko <mhocko@suse.com
> > <mailto:mhocko@suse.com>> wrote:
> >
> > On Thu 22-07-21 21:47:56, Suren Baghdasaryan wrote:
> > > On Thu, Jul 22, 2021, 7:04 PM Shakeel Butt <shakeelb@google.com
> > <mailto:shakeelb@google.com>> wrote:
> > >
> > > > On Thu, Jul 22, 2021 at 6:14 PM Suren Baghdasaryan
> > <surenb@google.com <mailto:surenb@google.com>>
> > > > wrote:
> > > > >
> > > > [...]
> > > > > +
> > > > > + mmap_read_lock(mm);
> > > >
> > > > How about mmap_read_trylock(mm) and return -EAGAIN on failure?
> > > >
> > >
> > > That sounds like a good idea. Thanks! I'll add that in the next
> > respin.
> >
> > Why is that a good idea? Can you do anything meaningful about the
> > failure other than immediately retry the syscall and hope for the best?
> >
> >
> > I was thinking if this syscall implements "best effort without blocking"
> > approach then for a more strict usage user can simply retry. However
> > retrying means issuing another syscall, so additional overhead...
> > I guess such "best effort" approach would be unusual for a syscall, so
> > maybe we can keep it as it is now and if such "do not block" mode is
> > needed we can use flags to implement it later?
>
> The process is dying, so I am not sure what we are trying to optimize
> here in respect to locking ...
Trying not to block the caller, which is likely a system health
monitoring process. However, if not blocking is important, it can
issue this syscall from a separate thread... Let's scratch that "do
not block" mode and keep it simple as it is now.
>
>
> --
> Thanks,
>
> David / dhildenb
>
> --
> To unsubscribe from this group and stop receiving emails from it, send an email to kernel-team+unsubscribe@android.com.
>
next prev parent reply other threads:[~2021-07-23 8:19 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-23 1:14 [PATCH v3 1/2] mm: introduce process_mrelease system call Suren Baghdasaryan
2021-07-23 1:14 ` [PATCH v3 2/2] mm: wire up syscall process_mrelease Suren Baghdasaryan
2021-07-23 2:03 ` [PATCH v3 1/2] mm: introduce process_mrelease system call Shakeel Butt
[not found] ` <CAJuCfpFZeQez77CB7odfaSpi3JcLQ_Nz0WvDTsra1VPoA-j7sg@mail.gmail.com>
2021-07-23 6:20 ` Michal Hocko
[not found] ` <CAJuCfpGSZwVgZ=FxhCV-uC_mzC7O-v-3k3tm-F6kOB7WM9t9tw@mail.gmail.com>
2021-07-23 8:15 ` David Hildenbrand
2021-07-23 8:18 ` Suren Baghdasaryan [this message]
2021-07-23 8:53 ` Michal Hocko
2021-07-23 13:46 ` Shakeel Butt
2021-07-23 16:08 ` Suren Baghdasaryan
2021-07-23 17:00 ` Shakeel Butt
2021-07-26 7:27 ` Michal Hocko
2021-07-26 13:43 ` Shakeel Butt
2021-08-02 19:53 ` Suren Baghdasaryan
2021-08-02 20:05 ` Shakeel Butt
2021-08-02 20:08 ` Suren Baghdasaryan
2021-08-02 22:16 ` Suren Baghdasaryan
2021-07-23 13:40 ` Shakeel Butt
2021-07-26 8:20 ` Michal Hocko
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=CAJuCfpFSi2eLQL1YkHOubX+53Aa1ngZ1hS2+QervFnt5dLEQSw@mail.gmail.com \
--to=surenb@google.com \
--cc=akpm@linux-foundation.org \
--cc=christian.brauner@ubuntu.com \
--cc=christian@brauner.io \
--cc=david@redhat.com \
--cc=fweimer@redhat.com \
--cc=guro@fb.com \
--cc=hannes@cmpxchg.org \
--cc=hch@infradead.org \
--cc=jannh@google.com \
--cc=jengelh@inai.de \
--cc=kernel-team@android.com \
--cc=linux-api@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=luto@kernel.org \
--cc=mhocko@suse.com \
--cc=minchan@kernel.org \
--cc=oleg@redhat.com \
--cc=riel@surriel.com \
--cc=rientjes@google.com \
--cc=shakeelb@google.com \
--cc=timmurray@google.com \
--cc=willy@infradead.org \
/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).