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From: Jason Gunthorpe <jgg@ziepe.ca>
To: Michal Hocko <mhocko@suse.com>
Cc: Juergen Gross <jgross@suse.com>,
	linux-mm@kvack.org, lkml <linux-kernel@vger.kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>,
	Jerome Glisse <jglisse@redhat.com>
Subject: Re: blocking vs. non-blocking mmu notifiers
Date: Wed, 23 Mar 2022 14:04:04 -0300	[thread overview]
Message-ID: <20220323170404.GK64706@ziepe.ca> (raw)
In-Reply-To: <YjtPpxlE/zWwnJ0W@dhcp22.suse.cz>

On Wed, Mar 23, 2022 at 05:49:43PM +0100, Michal Hocko wrote:
> > The bug here is that prior to commit a81461b0546c ("xen/gntdev: update
> > to new mmu_notifier semantic") wired the mn_invl_range_start() which
> > takes a mutex to invalidate_page, which is defined to run in an atomic
> > context.
> 
> Yeah, we have already identified that but quickly realized that the
> whole mmu notifier overhaul which this fix depends on would be no no for
> backporting to our older code base. So we are trying to find our way
> around that.

IMHO you don't need everything, just commit 369ea8242c0f ("mm/rmap:
update to new mmu_notifier semantic v2") which adds the missing
start/end outside the lock for the page callbacks.

Then you can take safely a8146 into gntdev.

Jason


  reply	other threads:[~2022-03-23 17:04 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-23  8:43 Juergen Gross
2022-03-23  9:45 ` Michal Hocko
2022-03-23 16:31   ` Jason Gunthorpe
2022-03-23 16:49     ` Michal Hocko
2022-03-23 17:04       ` Jason Gunthorpe [this message]
2022-03-24 12:42         ` Michal Hocko

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