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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F0E9FC433EF for ; Thu, 28 Oct 2021 10:59:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DA357610FC for ; Thu, 28 Oct 2021 10:59:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230059AbhJ1LCY (ORCPT ); Thu, 28 Oct 2021 07:02:24 -0400 Received: from smtp-out2.suse.de ([195.135.220.29]:47378 "EHLO smtp-out2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230093AbhJ1LCY (ORCPT ); Thu, 28 Oct 2021 07:02:24 -0400 Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 454D91FD4B; Thu, 28 Oct 2021 10:59:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1635418796; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=zbNYXie6Hzu/qw+CQlU1pNMVLlxvFSRFIIQVne0mm/A=; b=bNz1I6ZABAMt8Dl4G3Tn26G74FtY89yFKIs9oSYIAdBladlFdguRX8/jVEu3rN725BrO4C aqnV6fskaxOVK3L71kMUr+uMwiA7gKJQBRpXB4MDDNsPpBtRipv/LEPd1uw9yowq6PUP08 2lKgmbDSHONB5ZySGN9l0z4USVQIkKg= Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 07D4713C5C; Thu, 28 Oct 2021 10:59:56 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id opa6AKyCemGQNgAAMHmgww (envelope-from ); Thu, 28 Oct 2021 10:59:56 +0000 From: Juergen Gross To: xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org Cc: Juergen Gross , Boris Ostrovsky , Stefano Stabellini , stable@vger.kernel.org, =?UTF-8?q?Marek=20Marczykowski-G=C3=B3recki?= Subject: [PATCH] xen/balloon: add late_initcall_sync() for initial ballooning done Date: Thu, 28 Oct 2021 12:59:52 +0200 Message-Id: <20211028105952.10011-1-jgross@suse.com> X-Mailer: git-send-email 2.26.2 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org When running as PVH or HVM guest with actual memory < max memory the hypervisor is using "populate on demand" in order to allow the guest to balloon down from its maximum memory size. For this to work correctly the guest must not touch more memory pages than its target memory size as otherwise the PoD cache will be exhausted and the guest is crashed as a result of that. In extreme cases ballooning down might not be finished today before the init process is started, which can consume lots of memory. In order to avoid random boot crashes in such cases, add a late init call to wait for ballooning down having finished for PVH/HVM guests. Cc: Reported-by: Marek Marczykowski-Górecki Signed-off-by: Juergen Gross --- drivers/xen/balloon.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c index 3a50f097ed3e..d19b851c3d3b 100644 --- a/drivers/xen/balloon.c +++ b/drivers/xen/balloon.c @@ -765,3 +765,23 @@ static int __init balloon_init(void) return 0; } subsys_initcall(balloon_init); + +static int __init balloon_wait_finish(void) +{ + if (!xen_domain()) + return -ENODEV; + + /* PV guests don't need to wait. */ + if (xen_pv_domain() || !current_credit()) + return 0; + + pr_info("Waiting for initial ballooning down having finished.\n"); + + while (current_credit()) + schedule_timeout_interruptible(HZ / 10); + + pr_info("Initial ballooning down finished.\n"); + + return 0; +} +late_initcall_sync(balloon_wait_finish); -- 2.26.2