From: Jerome Glisse <jglisse@redhat.com>
To: Ralph Campbell <rcampbell@nvidia.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
linux-rdma@vger.kernel.org, Leon Romanovsky <leonro@mellanox.com>,
Doug Ledford <dledford@redhat.com>,
Artemy Kovalyov <artemyko@mellanox.com>,
Moni Shoua <monis@mellanox.com>,
Mike Marciniszyn <mike.marciniszyn@intel.com>,
Kaike Wan <kaike.wan@intel.com>,
Dennis Dalessandro <dennis.dalessandro@intel.com>
Subject: Re: [PATCH v4 0/1] Use HMM for ODP v4
Date: Wed, 22 May 2019 18:06:49 -0400 [thread overview]
Message-ID: <20190522220649.GC20179@redhat.com> (raw)
In-Reply-To: <05e7f491-b8a4-4214-ab75-9ecf1128aaa6@nvidia.com>
On Wed, May 22, 2019 at 02:12:31PM -0700, Ralph Campbell wrote:
>
> On 5/22/19 1:12 PM, Jason Gunthorpe wrote:
> > On Wed, May 22, 2019 at 01:48:52PM -0400, Jerome Glisse wrote:
> >
> > > static void put_per_mm(struct ib_umem_odp *umem_odp)
> > > {
> > > struct ib_ucontext_per_mm *per_mm = umem_odp->per_mm;
> > > @@ -325,9 +283,10 @@ static void put_per_mm(struct ib_umem_odp *umem_odp)
> > > up_write(&per_mm->umem_rwsem);
> > > WARN_ON(!RB_EMPTY_ROOT(&per_mm->umem_tree.rb_root));
> > > - mmu_notifier_unregister_no_release(&per_mm->mn, per_mm->mm);
> > > + hmm_mirror_unregister(&per_mm->mirror);
> > > put_pid(per_mm->tgid);
> > > - mmu_notifier_call_srcu(&per_mm->rcu, free_per_mm);
> > > +
> > > + kfree(per_mm);
> >
> > Notice that mmu_notifier only uses SRCU to fence in-progress ops
> > callbacks, so I think hmm internally has the bug that this ODP
> > approach prevents.
> >
> > hmm should follow the same pattern ODP has and 'kfree_srcu' the hmm
> > struct, use container_of in the mmu_notifier callbacks, and use the
> > otherwise vestigal kref_get_unless_zero() to bail:
>
> You might also want to look at my patch where
> I try to fix some of these same issues (5/5).
>
> https://marc.info/?l=linux-mm&m=155718572908765&w=2
I need to review the patchset but i do not want to invert referencing
ie having mm hold reference on hmm. Will review tommorrow. I wanted to
do that today but did not had time.
next prev parent reply other threads:[~2019-05-22 22:06 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20190411181314.19465-1-jglisse@redhat.com>
[not found] ` <20190506195657.GA30261@ziepe.ca>
[not found] ` <20190521205321.GC3331@redhat.com>
[not found] ` <20190522005225.GA30819@ziepe.ca>
[not found] ` <20190522174852.GA23038@redhat.com>
2019-05-22 19:22 ` [PATCH v4 0/1] Use HMM for ODP v4 Jason Gunthorpe
2019-05-22 21:49 ` Jerome Glisse
2019-05-22 22:43 ` Jason Gunthorpe
2019-05-22 20:12 ` Jason Gunthorpe
2019-05-22 21:12 ` Ralph Campbell
2019-05-22 22:06 ` Jerome Glisse [this message]
2019-05-22 22:04 ` Jerome Glisse
2019-05-22 22:39 ` Jason Gunthorpe
2019-05-22 22:42 ` Jerome Glisse
2019-05-22 22:52 ` Jason Gunthorpe
[not found] ` <20190522235737.GD15389@ziepe.ca>
[not found] ` <20190523150432.GA5104@redhat.com>
[not found] ` <20190523154149.GB12159@ziepe.ca>
[not found] ` <20190523155207.GC5104@redhat.com>
[not found] ` <20190523163429.GC12159@ziepe.ca>
[not found] ` <20190523173302.GD5104@redhat.com>
[not found] ` <20190523175546.GE12159@ziepe.ca>
[not found] ` <20190523182458.GA3571@redhat.com>
[not found] ` <20190523191038.GG12159@ziepe.ca>
2019-05-24 6:40 ` Christoph Hellwig
2019-05-24 12:44 ` RFC: Run a dedicated hmm.git for 5.3 Jason Gunthorpe
2019-05-24 16:27 ` Daniel Vetter
2019-05-24 16:53 ` Jason Gunthorpe
2019-05-24 16:59 ` Daniel Vetter
2019-05-25 22:52 ` Andrew Morton
2019-05-27 19:12 ` Jason Gunthorpe
2019-06-06 15:25 ` Jason Gunthorpe
2019-06-06 19:53 ` Stephen Rothwell
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