From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-it0-f72.google.com (mail-it0-f72.google.com [209.85.214.72]) by kanga.kvack.org (Postfix) with ESMTP id 5A8FE6B0488 for ; Fri, 18 Nov 2016 17:47:12 -0500 (EST) Received: by mail-it0-f72.google.com with SMTP id o1so43902298ito.7 for ; Fri, 18 Nov 2016 14:47:12 -0800 (PST) Received: from userp1040.oracle.com (userp1040.oracle.com. [156.151.31.81]) by mx.google.com with ESMTPS id s74si3472425ita.89.2016.11.18.14.47.11 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 18 Nov 2016 14:47:11 -0800 (PST) Subject: Re: [PATCH v3 (re-send)] xen/gntdev: Use mempolicy instead of VM_IO flag to avoid NUMA balancing References: <1479413404-27332-1-git-send-email-boris.ostrovsky@oracle.com> <2bf041f3-8918-3c6f-8afb-c9edcc03dcd9@oracle.com> From: Boris Ostrovsky Message-ID: <05c24d23-0298-5b58-d0e8-095ba64cdf9b@oracle.com> Date: Fri, 18 Nov 2016 17:49:41 -0500 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable Sender: owner-linux-mm@kvack.org List-ID: To: Hugh Dickins Cc: 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 11/18/2016 05:27 PM, Hugh Dickins wrote: > 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 meani= ng >> ("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= =2E > A comment on why VM_MIXEDMAP is being used there would certainly be goo= d. > But I do find its use preferable to enlisting an unusual ->get_policy. OK, I'll set VM_MIXEDMAP then. I am still curious though why you feel get_policy is not appropriate here (beside the fact that so far it had limited use). It is essentially trying to say that the only policy to be consulted (in vma_policy_mof()) is of the vma itself and not of the task. -boris -- 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