From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754735AbcARLLK (ORCPT ); Mon, 18 Jan 2016 06:11:10 -0500 Received: from smtp.citrix.com ([66.165.176.89]:4603 "EHLO SMTP.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754375AbcARLLJ (ORCPT ); Mon, 18 Jan 2016 06:11:09 -0500 X-IronPort-AV: E=Sophos;i="5.22,312,1449532800"; d="scan'208";a="325853946" Message-ID: <569CC84A.1000401@citrix.com> Date: Mon, 18 Jan 2016 11:11:06 +0000 From: David Vrabel User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Icedove/31.8.0 MIME-Version: 1.0 To: Boris Ostrovsky , , CC: , Subject: Re: [Xen-devel] [PATCH] xen/gntdev: Don't allocate struct gntdev_copy_batch on stack References: <1452887025-27285-1-git-send-email-boris.ostrovsky@oracle.com> In-Reply-To: <1452887025-27285-1-git-send-email-boris.ostrovsky@oracle.com> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit X-DLP: MIA2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 15/01/16 19:43, Boris Ostrovsky wrote: > struct gntdev_copy_batch is over 1300 bytes in size, we shouldn't > put it on stack. > > Some compilers (e.g. 5.2.1) complain: > drivers/xen/gntdev.c: In function ‘gntdev_ioctl_grant_copy.isra.5’: > drivers/xen/gntdev.c:949:1: warning: the frame size of 1416 bytes > is larger than 1024 bytes [-Wframe-larger-than=] I thought I'd already reduced the size of this enough (from a batch size of 32 to 24) but this obviously isn't enough for 64-bit platforms. In the absence of any performance data on the best approach I would prefer just reducing the batch size to 16. David