From mboxrd@z Thu Jan 1 00:00:00 1970 From: Julien Grall Subject: [PATCH v2 09/20] xen/biomerge: Don't allow biovec to be merge when Linux is not using 4KB page Date: Thu, 9 Jul 2015 21:42:21 +0100 Message-ID: <1436474552-31789-10-git-send-email-julien.grall@citrix.com> References: <1436474552-31789-1-git-send-email-julien.grall@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta5.messagelabs.com ([195.245.231.135]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1ZDIfX-0008Co-T5 for xen-devel@lists.xenproject.org; Thu, 09 Jul 2015 20:43:43 +0000 In-Reply-To: <1436474552-31789-1-git-send-email-julien.grall@citrix.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: xen-devel@lists.xenproject.org Cc: ian.campbell@citrix.com, stefano.stabellini@eu.citrix.com, linux-kernel@vger.kernel.org, Julien Grall , David Vrabel , Boris Ostrovsky , linux-arm-kernel@lists.infradead.org List-Id: xen-devel@lists.xenproject.org When Linux is using 64K page granularity, every page will be slipt in multiple non-contiguous 4K MFN (page granularity of Xen). I'm not sure how to handle efficiently the check to know whether we can merge 2 biovec with a such case. So for now, always says that biovec are not mergeable. Signed-off-by: Julien Grall Cc: Konrad Rzeszutek Wilk Cc: Boris Ostrovsky Cc: David Vrabel --- Changes in v2: - Remove the workaround and check if the Linux page granularity is the same as Xen or not --- drivers/xen/biomerge.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/xen/biomerge.c b/drivers/xen/biomerge.c index 0edb91c..571567c 100644 --- a/drivers/xen/biomerge.c +++ b/drivers/xen/biomerge.c @@ -6,10 +6,17 @@ bool xen_biovec_phys_mergeable(const struct bio_vec *vec1, const struct bio_vec *vec2) { +#if XEN_PAGE_SIZE == PAGE_SIZE unsigned long mfn1 = pfn_to_mfn(page_to_pfn(vec1->bv_page)); unsigned long mfn2 = pfn_to_mfn(page_to_pfn(vec2->bv_page)); return __BIOVEC_PHYS_MERGEABLE(vec1, vec2) && ((mfn1 == mfn2) || ((mfn1+1) == mfn2)); +#else + /* XXX: bio_vec are not mergeable when using different page size in + * Xen and Linux + */ + return 0; +#endif } EXPORT_SYMBOL(xen_biovec_phys_mergeable); -- 2.1.4