From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id ED743C2D0B1 for ; Thu, 6 Feb 2020 08:52:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C1D8521741 for ; Thu, 6 Feb 2020 08:52:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728132AbgBFIwN (ORCPT ); Thu, 6 Feb 2020 03:52:13 -0500 Received: from mga03.intel.com ([134.134.136.65]:9873 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727778AbgBFIwM (ORCPT ); Thu, 6 Feb 2020 03:52:12 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga103.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 06 Feb 2020 00:52:12 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,409,1574150400"; d="scan'208";a="264531173" Received: from devel-ww.sh.intel.com ([10.239.48.128]) by fmsmga002.fm.intel.com with ESMTP; 06 Feb 2020 00:52:10 -0800 From: Wei Wang To: linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org Cc: tysand@google.com, mst@redhat.com, david@redhat.com, alexander.h.duyck@linux.intel.com, rientjes@google.com, mhocko@kernel.org, namit@vmware.com, penguin-kernel@I-love.SAKURA.ne.jp, wei.w.wang@intel.com Subject: [PATCH RFC] virtio_balloon: conservative balloon page shrinking Date: Thu, 6 Feb 2020 16:01:47 +0800 Message-Id: <1580976107-16013-1-git-send-email-wei.w.wang@intel.com> X-Mailer: git-send-email 2.7.4 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org There are cases that users want to shrink balloon pages after the pagecache depleted. The conservative_shrinker lets the shrinker shrink balloon pages when all the pagecache has been reclaimed. Signed-off-by: Wei Wang --- drivers/virtio/virtio_balloon.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c index 93f995f6cf36..b4c5bb13a867 100644 --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -42,6 +42,10 @@ static struct vfsmount *balloon_mnt; #endif +static bool conservative_shrinker = true; +module_param(conservative_shrinker, bool, 0644); +MODULE_PARM_DESC(conservative_shrinker, "conservatively shrink balloon pages"); + enum virtio_balloon_vq { VIRTIO_BALLOON_VQ_INFLATE, VIRTIO_BALLOON_VQ_DEFLATE, @@ -796,6 +800,10 @@ static unsigned long shrink_balloon_pages(struct virtio_balloon *vb, { unsigned long pages_freed = 0; + /* Balloon pages only gets shrunk when the pagecache depleted */ + if (conservative_shrinker && global_node_page_state(NR_FILE_PAGES)) + return 0; + /* * One invocation of leak_balloon can deflate at most * VIRTIO_BALLOON_ARRAY_PFNS_MAX balloon pages, so we call it @@ -837,7 +845,11 @@ static unsigned long virtio_balloon_shrinker_count(struct shrinker *shrinker, struct virtio_balloon, shrinker); unsigned long count; - count = vb->num_pages / VIRTIO_BALLOON_PAGES_PER_PAGE; + if (conservative_shrinker && global_node_page_state(NR_FILE_PAGES)) + count = 0; + else + count = vb->num_pages / VIRTIO_BALLOON_PAGES_PER_PAGE; + count += vb->num_free_page_blocks * VIRTIO_BALLOON_HINT_BLOCK_PAGES; return count; -- 2.17.1