From: Matthew Wilcox <willy@infradead.org>
To: Jason Gunthorpe <jgg@ziepe.ca>
Cc: linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org,
linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org
Subject: Re: Freeing page tables through RCU
Date: Fri, 26 Feb 2021 16:03:54 +0000 [thread overview]
Message-ID: <20210226160354.GE2723601@casper.infradead.org> (raw)
In-Reply-To: <20210226144200.GV2643399@ziepe.ca>
On Fri, Feb 26, 2021 at 10:42:00AM -0400, Jason Gunthorpe wrote:
> On Thu, Feb 25, 2021 at 08:58:20PM +0000, Matthew Wilcox wrote:
>
> > I'd like to hear better ideas than this.
>
> You didn't like my suggestion to put a sleepable lock around the
> freeing of page tables during flushing?
>
> I still don't see how you convert the sleepable page walkers to use
> rcu??
I don't want to convert the sleepable ones to use RCU ... I want to
convert the non-sleeping ones to use RCU. A page_table_free_lock might
work, but it might have its own problems later (eg a sleeping lock can't
be acquired under RCU or spinlock, and it can't be a spinlock because
it'd have to be held while we wait for IPIs).
I think it would solve my immediate problem, and I wonder if it might
solve some other problems ...
next prev parent reply other threads:[~2021-02-26 16:04 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-25 20:58 Freeing page tables through RCU Matthew Wilcox
2021-02-26 14:42 ` Jason Gunthorpe
2021-02-26 16:03 ` Matthew Wilcox [this message]
2021-02-26 16:21 ` Jason Gunthorpe
2021-02-26 16:12 ` Gerald Schaefer
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