From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753315Ab3CRLDh (ORCPT ); Mon, 18 Mar 2013 07:03:37 -0400 Received: from cantor2.suse.de ([195.135.220.15]:34499 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752030Ab3CRLDf (ORCPT ); Mon, 18 Mar 2013 07:03:35 -0400 Date: Mon, 18 Mar 2013 12:03:34 +0100 From: Michal Hocko To: "K. Y. Srinivasan" Cc: gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, devel@linuxdriverproject.org, olaf@aepfle.de, apw@canonical.com, andi@firstfloor.org, akpm@linux-foundation.org, linux-mm@kvack.org, kamezawa.hiroyuki@gmail.com, hannes@cmpxchg.org, yinghan@google.com Subject: Re: [PATCH 1/2] mm: Export split_page() Message-ID: <20130318110334.GI10192@dhcp22.suse.cz> References: <1363470088-24565-1-git-send-email-kys@microsoft.com> <1363470125-24606-1-git-send-email-kys@microsoft.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1363470125-24606-1-git-send-email-kys@microsoft.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat 16-03-13 14:42:04, K. Y. Srinivasan wrote: > The split_page() function will be very useful for balloon drivers. On Hyper-V, > it will be very efficient to use 2M allocations in the guest as this (a) makes > the ballooning protocol with the host that much more efficient and (b) moving > memory in 2M chunks minimizes fragmentation in the host. Export the split_page() > function to let the guest allocations be in 2M chunks while the host is free to > return this memory at arbitrary granularity. > > Signed-off-by: K. Y. Srinivasan I do not have any objections to exporting the symbol (at least we prevent drivers code from inventing their own split_page) but the Hyper-V specific description should go into Hyper-V patch IMO. So for the export with a short note that the symbol will be used by Hyper-V Acked-by: Michal Hocko > --- > mm/page_alloc.c | 1 + > 1 files changed, 1 insertions(+), 0 deletions(-) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 6cacfee..7e0ead6 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -1404,6 +1404,7 @@ void split_page(struct page *page, unsigned int order) > for (i = 1; i < (1 << order); i++) > set_page_refcounted(page + i); > } > +EXPORT_SYMBOL_GPL(split_page); > > static int __isolate_free_page(struct page *page, unsigned int order) > { > -- > 1.7.4.1 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- Michal Hocko SUSE Labs