From patchwork Thu May 14 17:00:56 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Julien Grall X-Patchwork-Id: 6408271 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id F0846C0432 for ; Thu, 14 May 2015 17:28:35 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 14C62203E9 for ; Thu, 14 May 2015 17:28:35 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 2FE83203DA for ; Thu, 14 May 2015 17:28:34 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1YswsX-0000WY-BV; Thu, 14 May 2015 17:25:01 +0000 Received: from smtp.citrix.com ([66.165.176.89]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1YswmD-0002vF-Qp for linux-arm-kernel@lists.infradead.org; Thu, 14 May 2015 17:18:32 +0000 X-IronPort-AV: E=Sophos;i="5.13,430,1427760000"; d="scan'208";a="262772965" From: Julien Grall To: Subject: [RFC 16/23] xen/events: fifo: Make it running on 64KB granularity Date: Thu, 14 May 2015 18:00:56 +0100 Message-ID: <1431622863-28575-17-git-send-email-julien.grall@citrix.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1431622863-28575-1-git-send-email-julien.grall@citrix.com> References: <1431622863-28575-1-git-send-email-julien.grall@citrix.com> MIME-Version: 1.0 X-DLP: MIA2 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20150514_101830_129265_AA8F1922 X-CRM114-Status: GOOD ( 10.85 ) X-Spam-Score: -5.0 (-----) Cc: ian.campbell@citrix.com, stefano.stabellini@eu.citrix.com, Konrad Rzeszutek Wilk , tim@xen.org, linux-kernel@vger.kernel.org, Julien Grall , David Vrabel , Boris Ostrovsky , linux-arm-kernel@lists.infradead.org X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 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: * 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. Signed-off-by: Julien Grall Cc: Konrad Rzeszutek Wilk Cc: Boris Ostrovsky Cc: David Vrabel Reviewed-by: 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 704d36e..24b97bd 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 diff --git a/drivers/xen/events/events_fifo.c b/drivers/xen/events/events_fifo.c index ed673e1..d53c297 100644 --- a/drivers/xen/events/events_fifo.c +++ b/drivers/xen/events/events_fifo.c @@ -54,7 +54,7 @@ #include "events_internal.h" -#define EVENT_WORDS_PER_PAGE (PAGE_SIZE / sizeof(event_word_t)) +#define EVENT_WORDS_PER_PAGE (XEN_PAGE_SIZE / sizeof(event_word_t)) #define MAX_EVENT_ARRAY_PAGES (EVTCHN_FIFO_NR_CHANNELS / EVENT_WORDS_PER_PAGE) struct evtchn_fifo_queue {