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 C5DBCC433FE for ; Fri, 29 Oct 2021 07:49:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AEAEB60234 for ; Fri, 29 Oct 2021 07:49:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232323AbhJ2HwU (ORCPT ); Fri, 29 Oct 2021 03:52:20 -0400 Received: from smtp-out1.suse.de ([195.135.220.28]:42388 "EHLO smtp-out1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232302AbhJ2HwL (ORCPT ); Fri, 29 Oct 2021 03:52:11 -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-out1.suse.de (Postfix) with ESMTPS id 13B7921971; Fri, 29 Oct 2021 07:49:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1635493782; 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=cEHSevouYw8lnbcB9mvJJwAH561ddSGhR9uQkll/Ybg=; b=ZmMFSg7HmY3N5x7iTSAMm4Y3XP4uycpYHsJ/QcagIeHfvd81YwIObys7En+h15ENPVGFm3 oWCRhBglR/uMGpRzFe2Q/ZGTb/lHyzzufZBszoMQL5le4q4uYWgxPtsthnpAvypCTgPqgJ elxeVELo3y5KwimhI58Sg0m/AxIZTaM= 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 C937C13B27; Fri, 29 Oct 2021 07:49:41 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id HHUYL5Wne2GPfwAAMHmgww (envelope-from ); Fri, 29 Oct 2021 07:49:41 +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 v2] xen/balloon: add late_initcall_sync() for initial ballooning done Date: Fri, 29 Oct 2021 09:49:31 +0200 Message-Id: <20211029074931.20657-1-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: linux-kernel@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. Warn on console if ballooning stalls for more than 1 minute, panic() after stalling for more than 3 minutes. Cc: Reported-by: Marek Marczykowski-Górecki Signed-off-by: Juergen Gross --- V2: - add warning and panic() when stalling (Marek Marczykowski-Górecki) - don't wait if credit > 0 --- drivers/xen/balloon.c | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c index 3a50f097ed3e..c0c1c754e515 100644 --- a/drivers/xen/balloon.c +++ b/drivers/xen/balloon.c @@ -765,3 +765,38 @@ static int __init balloon_init(void) return 0; } subsys_initcall(balloon_init); + +static int __init balloon_wait_finish(void) +{ + long credit, last_credit = 0; + unsigned long last_changed; + + 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 ((credit = current_credit()) < 0) { + if (credit != last_credit) { + last_changed = jiffies; + last_credit = credit; + } + if (jiffies - last_changed >= HZ * 60) { + pr_warn_once("Initial ballooning stalling for 60s, %ld pages need to be freed.\n", + -credit); + } + if (jiffies - last_changed >= 3 * HZ * 60) + panic("Initial ballooning failed!\n"); + + schedule_timeout_interruptible(HZ / 10); + } + + pr_info("Initial ballooning down finished.\n"); + + return 0; +} +late_initcall_sync(balloon_wait_finish); -- 2.26.2