Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758050Ab3ENSVK (ORCPT ); Tue, 14 May 2013 14:21:10 -0400 Received: from mail-ve0-f175.google.com ([209.85.128.175]:38448 "EHLO mail-ve0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757923Ab3ENSUz (ORCPT ); Tue, 14 May 2013 14:20:55 -0400 From: Konrad Rzeszutek Wilk To: bob.liu@oracle.com, dan.magenheimer@oracle.com, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, linux-mm@kvack.org, xen-devel@lists.xensource.com Cc: Konrad Rzeszutek Wilk Subject: [PATCH 9/9] xen/tmem: Don't use self[ballooning|shrinking] if frontswap is off. Date: Tue, 14 May 2013 14:09:26 -0400 Message-Id: <1368554966-30469-10-git-send-email-konrad.wilk@oracle.com> X-Mailer: git-send-email 1.7.7.6 In-Reply-To: <1368554966-30469-1-git-send-email-konrad.wilk@oracle.com> References: <1368554966-30469-1-git-send-email-konrad.wilk@oracle.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3462 Lines: 80 There is no point. We would just squeeze the guest to put more and more pages in the swap disk without any purpose. The only time it makes sense to use the selfballooning and shrinking is when frontswap is being utilized. Signed-off-by: Konrad Rzeszutek Wilk --- Documentation/kernel-parameters.txt | 3 ++- drivers/xen/tmem.c | 8 ++++++++ drivers/xen/xen-selfballoon.c | 15 ++++++--------- 3 files changed, 16 insertions(+), 10 deletions(-) diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 3de01ed..6e3b18a 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -3014,7 +3014,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted. tmem.frontswap=0|1 [KNL, XEN] Default is on (1). Disable the usage of the frontswap - API to send swap pages to the hypervisor. + API to send swap pages to the hypervisor. If disabled + the selfballooning and selfshrinking are force disabled. tmem.selfballooning=0|1 [KNL, XEN] Default is on (1). Disable the driving of swap pages diff --git a/drivers/xen/tmem.c b/drivers/xen/tmem.c index c1df0ff..18e8bd8 100644 --- a/drivers/xen/tmem.c +++ b/drivers/xen/tmem.c @@ -403,6 +403,14 @@ static int xen_tmem_init(void) } #endif #ifdef CONFIG_XEN_SELFBALLOONING + /* + * There is no point of driving pages to the swap system if they + * aren't going anywhere in tmem universe. + */ + if (!frontswap) { + selfshrinking = false; + selfballooning = false; + } xen_selfballoon_init(selfballooning, selfshrinking); #endif return 0; diff --git a/drivers/xen/xen-selfballoon.c b/drivers/xen/xen-selfballoon.c index 5d637e2..f70984a8 100644 --- a/drivers/xen/xen-selfballoon.c +++ b/drivers/xen/xen-selfballoon.c @@ -53,15 +53,12 @@ * System configuration note: Selfballooning should not be enabled on * systems without a sufficiently large swap device configured; for best * results, it is recommended that total swap be increased by the size - * of the guest memory. Also, while technically not required to be - * configured, it is highly recommended that frontswap also be configured - * and enabled when selfballooning is running. So, selfballooning - * is disabled by default if frontswap is not configured and can only - * be enabled with the "tmem.selfballooning=1" kernel boot option; similarly - * selfballooning is enabled by default if frontswap is configured and - * can be disabled with the "tmem.selfballooning=0" kernel boot option. Finally, - * when frontswap is configured,frontswap-selfshrinking can be disabled - * with the "tmem.selfshrink=0" kernel boot option. + * of the guest memory. Note, that selfballooning should be disabled by default + * if frontswap is not configured. Similarly selfballooning should be enabled + * by default if frontswap is configured and can be disabled with the + * "tmem.selfballooning=0" kernel boot option. Finally, when frontswap is + * configured, frontswap-selfshrinking can be disabled with the + * "tmem.selfshrink=0" kernel boot option. * * Selfballooning is disallowed in domain0 and force-disabled. * -- 1.7.7.6 -- 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/