Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755001AbbGPQUb (ORCPT ); Thu, 16 Jul 2015 12:20:31 -0400 Received: from smtp.citrix.com ([66.165.176.89]:58894 "EHLO SMTP.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752203AbbGPQU3 (ORCPT ); Thu, 16 Jul 2015 12:20:29 -0400 X-IronPort-AV: E=Sophos;i="5.15,488,1432598400"; d="scan'208";a="281665749" Message-ID: <55A7D955.5090203@citrix.com> Date: Thu, 16 Jul 2015 17:18:29 +0100 From: Julien Grall User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Stefano Stabellini CC: , , David Vrabel , , Boris Ostrovsky , Subject: Re: [Xen-devel] [PATCH v2 13/20] xen/events: fifo: Make it running on 64KB granularity References: <1436474552-31789-1-git-send-email-julien.grall@citrix.com> <1436474552-31789-14-git-send-email-julien.grall@citrix.com> In-Reply-To: Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit X-DLP: MIA1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2304 Lines: 70 Hi Stefano, On 16/07/2015 16:43, Stefano Stabellini wrote: > On Thu, 9 Jul 2015, Julien Grall wrote: >> Only use the first 4KB of the page to store the events channel info. It >> means that we will wast 60KB every time we allocate page for: > ^ waste > >> * control block: a page is allocating per CPU >> * event array: a page is allocating everytime we need to expand it >> >> I think we can reduce the memory waste for the 2 areas by: >> >> * control block: sharing between multiple vCPUs. Although it will >> require some bookkeeping in order to not free the page when the CPU >> goes offline and the other CPUs sharing the page still there >> >> * event array: always extend the array event by 64K (i.e 16 4K >> chunk). That would require more care when we fail to expand the >> event channel. > > But this is not implemented in this series, right? Yes, it's some ideas to improve the code. > > >> Signed-off-by: Julien Grall >> Cc: Konrad Rzeszutek Wilk >> Cc: Boris Ostrovsky >> Cc: David Vrabel >> --- >> drivers/xen/events/events_base.c | 2 +- >> drivers/xen/events/events_fifo.c | 2 +- >> 2 files changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c >> index 96093ae..858d2f6 100644 >> --- a/drivers/xen/events/events_base.c >> +++ b/drivers/xen/events/events_base.c >> @@ -40,11 +40,11 @@ >> #include >> #include >> #include >> -#include >> #endif >> #include >> #include >> #include >> +#include >> >> #include >> #include > > Spurious change? No, xen/page.h was only included for x86 before. Now, it's included for every architecture. This is required in order to get XEN_PAGE_SIZE. Regards, -- Julien Grall -- 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/