From: Hugh Dickins <hughd@google.com>
To: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Hugh Dickins <hughd@google.com>,
Mel Gorman <mgorman@techsingularity.net>,
david.vrabel@citrix.com, jgross@suse.com,
xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, olaf@aepfle.de
Subject: Re: [PATCH v3 (re-send)] xen/gntdev: Use mempolicy instead of VM_IO flag to avoid NUMA balancing
Date: Fri, 18 Nov 2016 14:27:12 -0800 (PST) [thread overview]
Message-ID: <alpine.LSU.2.11.1611181421470.10145@eggly.anvils> (raw)
In-Reply-To: <2bf041f3-8918-3c6f-8afb-c9edcc03dcd9@oracle.com>
On Fri, 18 Nov 2016, Boris Ostrovsky wrote:
> On 11/18/2016 04:51 PM, Hugh Dickins wrote:
> > Hmm, sorry, but this seems overcomplicated to me: ingenious, but an
> > unusual use of the ->get_policy method, which is a little worrying,
> > since it has only been used for shmem (+ shm and kernfs) until now.
> >
> > Maybe I'm wrong, but wouldn't substituting VM_MIXEDMAP for VM_IO
> > solve the problem more simply?
>
> It would indeed. I didn't want to use it because it has specific meaning
> ("Can contain "struct page" and pure PFN pages") and that didn't seem
> like the right flag to describe this vma.
It is okay if it contains 0 pure PFN pages; and no worse than VM_IO was.
A comment on why VM_MIXEDMAP is being used there would certainly be good.
But I do find its use preferable to enlisting an unusual ->get_policy.
Hugh
next prev parent reply other threads:[~2016-11-18 22:27 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-17 20:10 Boris Ostrovsky
2016-11-18 7:59 ` Olaf Hering
2016-11-18 21:51 ` Hugh Dickins
2016-11-18 22:14 ` Boris Ostrovsky
2016-11-18 22:27 ` Hugh Dickins [this message]
2016-11-18 22:49 ` Boris Ostrovsky
2016-11-18 23:27 ` Hugh Dickins
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