From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f71.google.com (mail-pg0-f71.google.com [74.125.83.71]) by kanga.kvack.org (Postfix) with ESMTP id EA2C66B0487 for ; Fri, 18 Nov 2016 17:27:20 -0500 (EST) Received: by mail-pg0-f71.google.com with SMTP id f188so270946746pgc.1 for ; Fri, 18 Nov 2016 14:27:20 -0800 (PST) Received: from mail-pg0-x22c.google.com (mail-pg0-x22c.google.com. [2607:f8b0:400e:c05::22c]) by mx.google.com with ESMTPS id f192si10103499pfa.60.2016.11.18.14.27.20 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 18 Nov 2016 14:27:20 -0800 (PST) Received: by mail-pg0-x22c.google.com with SMTP id 3so107247849pgd.0 for ; Fri, 18 Nov 2016 14:27:20 -0800 (PST) Date: Fri, 18 Nov 2016 14:27:12 -0800 (PST) From: Hugh Dickins Subject: Re: [PATCH v3 (re-send)] xen/gntdev: Use mempolicy instead of VM_IO flag to avoid NUMA balancing In-Reply-To: <2bf041f3-8918-3c6f-8afb-c9edcc03dcd9@oracle.com> Message-ID: References: <1479413404-27332-1-git-send-email-boris.ostrovsky@oracle.com> <2bf041f3-8918-3c6f-8afb-c9edcc03dcd9@oracle.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Boris Ostrovsky Cc: Hugh Dickins , Mel Gorman , david.vrabel@citrix.com, jgross@suse.com, xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, olaf@aepfle.de 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 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org