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Date:   Fri, 5 Feb 2021 16:13:51 -0500
To:     Chuck Lever <chuck.lever@oracle.com>
Cc:     Neil Brown <neilb@suse.de>,
        Linux NFS Mailing List <linux-nfs@vger.kernel.org>
Subject: Re: releasing result pages in svc_xprt_release()
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From:   bfields@fieldses.org (J. Bruce Fields)
Precedence: bulk

On Fri, Feb 05, 2021 at 08:20:28PM +0000, Chuck Lever wrote:
> Baby steps.
> 
> Because I'm perverse I started with bulk page freeing. In the course
> of trying to invent a new API, I discovered there already is a batch
> free_page() function called release_pages().
> 
> It seems to work as advertised for pages that are truly no longer
> in use (ie RPC/RDMA pages) but not for pages that are still in flight
> but released (ie TCP pages).
> 
> release_pages() chains the pages in the passed-in array onto a list
> by their page->lru fields. This seems to be a problem if a page
> is still in use.

I thought I remembered reading an lwn article about bulk page
allocation.  Looking around now all I can see is

	https://lwn.net/Articles/684616/
	https://lwn.net/Articles/711075/

and I can't tell if any of that work was ever finished.

--b.