From: Michal Hocko <mhocko@suse.com>
To: Jason Gunthorpe <jgg@ziepe.ca>
Cc: "Sean Christopherson" <seanjc@google.com>,
"Andrew Morton" <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
"David Rientjes" <rientjes@google.com>,
"Ben Gardon" <bgardon@google.com>,
"Jérôme Glisse" <jglisse@redhat.com>,
"Andrea Arcangeli" <aarcange@redhat.com>,
"Johannes Weiner" <hannes@cmpxchg.org>,
"Dimitri Sivanich" <dimitri.sivanich@hpe.com>
Subject: Re: [PATCH] mm/oom_kill: Ensure MMU notifier range_end() is paired with range_start()
Date: Thu, 11 Mar 2021 17:20:25 +0100 [thread overview]
Message-ID: <YEpDJ/pPioG9ndYX@dhcp22.suse.cz> (raw)
In-Reply-To: <20210311002807.GQ444867@ziepe.ca>
On Wed 10-03-21 20:28:07, Jason Gunthorpe wrote:
> On Wed, Mar 10, 2021 at 01:31:17PM -0800, Sean Christopherson wrote:
> > Invoke the MMU notifier's .invalidate_range_end() callbacks even if one
> > of the .invalidate_range_start() callbacks failed. If there are multiple
> > notifiers, the notifier that did not fail may have performed actions in
> > its ...start() that it expects to unwind via ...end(). Per the
> > mmu_notifier_ops documentation, ...start() and ...end() must be paired.
>
> No this is not OK, if invalidate_start returns EBUSY invalidate_end
> should *not* be called.
Yes, this is what I remember when introducing nonblock interface. So I
agree with Jason this patch is not correct. The interface is subtle but
I remember we couldn't come up with something more robust and still
memory with notifiers to be reapable.
--
Michal Hocko
SUSE Labs
prev parent reply other threads:[~2021-03-11 16:21 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-10 21:31 [PATCH] mm/oom_kill: Ensure MMU notifier range_end() is paired with range_start() Sean Christopherson
2021-03-11 0:06 ` Andrew Morton
2021-03-11 0:28 ` Jason Gunthorpe
2021-03-11 1:20 ` Sean Christopherson
2021-03-11 1:50 ` Jason Gunthorpe
2021-03-11 7:22 ` Sean Christopherson
2021-03-11 16:20 ` Michal Hocko [this message]
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=YEpDJ/pPioG9ndYX@dhcp22.suse.cz \
--to=mhocko@suse.com \
--cc=aarcange@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=bgardon@google.com \
--cc=dimitri.sivanich@hpe.com \
--cc=hannes@cmpxchg.org \
--cc=jgg@ziepe.ca \
--cc=jglisse@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=rientjes@google.com \
--cc=seanjc@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).