From patchwork Tue Jun 29 09:47:49 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luis Henriques X-Patchwork-Id: 12349599 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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY 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 5348AC11F69 for ; Tue, 29 Jun 2021 09:47:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3587561DCB for ; Tue, 29 Jun 2021 09:47:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232987AbhF2JuV (ORCPT ); Tue, 29 Jun 2021 05:50:21 -0400 Received: from smtp-out2.suse.de ([195.135.220.29]:56228 "EHLO smtp-out2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232673AbhF2JuT (ORCPT ); Tue, 29 Jun 2021 05:50:19 -0400 Received: from imap.suse.de (imap-alt.suse-dmz.suse.de [192.168.254.47]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 8192E203C5; Tue, 29 Jun 2021 09:47:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1624960071; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=vPX0Meh0V+vU/WN0+CnpfUFks6WEAxIlKLouk3smEHU=; b=JRk16IAbi/4Y3IWvG62/cNEPrbENe/I3rgwf0EIx+FiIRlUVPVJh5i8QzKlGdBCe+5o22g cuD073h0EYiPy7AaM1AgLY0ovLMiQ3ej3KlVfMJw5A56rfTO+WzaS4+c8VYmN6syiRiBlo N7fgsuDMslCVRDjjHDdIvLuZK4zEnDQ= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1624960071; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=vPX0Meh0V+vU/WN0+CnpfUFks6WEAxIlKLouk3smEHU=; b=h2f0iVXPi3yOt1lZtwyNCif1YVAuSjrl+kLEPjLdeqSqsbIVKIiuj/Gu0UHTU982fA9fQw aqL4N8ay9YJXUdBQ== Received: from imap3-int (imap-alt.suse-dmz.suse.de [192.168.254.47]) by imap.suse.de (Postfix) with ESMTP id 1155511906; Tue, 29 Jun 2021 09:47:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1624960071; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=vPX0Meh0V+vU/WN0+CnpfUFks6WEAxIlKLouk3smEHU=; b=JRk16IAbi/4Y3IWvG62/cNEPrbENe/I3rgwf0EIx+FiIRlUVPVJh5i8QzKlGdBCe+5o22g cuD073h0EYiPy7AaM1AgLY0ovLMiQ3ej3KlVfMJw5A56rfTO+WzaS4+c8VYmN6syiRiBlo N7fgsuDMslCVRDjjHDdIvLuZK4zEnDQ= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1624960071; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=vPX0Meh0V+vU/WN0+CnpfUFks6WEAxIlKLouk3smEHU=; b=h2f0iVXPi3yOt1lZtwyNCif1YVAuSjrl+kLEPjLdeqSqsbIVKIiuj/Gu0UHTU982fA9fQw aqL4N8ay9YJXUdBQ== Received: from director2.suse.de ([192.168.254.72]) by imap3-int with ESMTPSA id cJZNAUfs2mBqawAALh3uQQ (envelope-from ); Tue, 29 Jun 2021 09:47:51 +0000 Received: from localhost (brahms [local]) by brahms (OpenSMTPD) with ESMTPA id e3d81f62; Tue, 29 Jun 2021 09:47:49 +0000 (UTC) From: Luis Henriques To: Jeff Layton , Ilya Dryomov Cc: ceph-devel@vger.kernel.org, linux-kernel@vger.kernel.org, Luis Henriques , stable@vger.kernel.org Subject: [RFC PATCH v2 2/2] ceph: reduce contention in ceph_check_delayed_caps() Date: Tue, 29 Jun 2021 10:47:49 +0100 Message-Id: <20210629094749.25253-3-lhenriques@suse.de> In-Reply-To: <20210629094749.25253-1-lhenriques@suse.de> References: <20210629094749.25253-1-lhenriques@suse.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: ceph-devel@vger.kernel.org Function ceph_check_delayed_caps() is called from the mdsc->delayed_work workqueue and it can be kept looping for quite some time if caps keep being added back to the mdsc->cap_delay_list. This may result in the watchdog tainting the kernel with the softlockup flag. This patch breaks this loop if the caps have been recently (i.e. during the loop execution). Any new caps added to the list will be handled in the next run. Cc: stable@vger.kernel.org Link: https://tracker.ceph.com/issues/46284 Signed-off-by: Luis Henriques --- fs/ceph/caps.c | 17 ++++++++++++++++- fs/ceph/mds_client.c | 7 ++++--- fs/ceph/super.h | 2 +- 3 files changed, 21 insertions(+), 5 deletions(-) diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c index a5e93b185515..c79b8dff25d7 100644 --- a/fs/ceph/caps.c +++ b/fs/ceph/caps.c @@ -4224,11 +4224,19 @@ void ceph_handle_caps(struct ceph_mds_session *session, /* * Delayed work handler to process end of delayed cap release LRU list. + * + * If new caps are added to the list while processing it, these won't get + * processed in this run. In this case, the ci->i_hold_caps_max will be + * returned so that the work can be scheduled accordingly. */ -void ceph_check_delayed_caps(struct ceph_mds_client *mdsc) +unsigned long ceph_check_delayed_caps(struct ceph_mds_client *mdsc) { struct inode *inode; struct ceph_inode_info *ci; + struct ceph_mount_options *opt = mdsc->fsc->mount_options; + unsigned long delay_max = opt->caps_wanted_delay_max * HZ; + unsigned long loop_start = jiffies; + unsigned long delay = 0; dout("check_delayed_caps\n"); spin_lock(&mdsc->cap_delay_lock); @@ -4236,6 +4244,11 @@ void ceph_check_delayed_caps(struct ceph_mds_client *mdsc) ci = list_first_entry(&mdsc->cap_delay_list, struct ceph_inode_info, i_cap_delay_list); + if (time_before(loop_start, ci->i_hold_caps_max - delay_max)) { + dout("%s caps added recently. Exiting loop", __func__); + delay = ci->i_hold_caps_max; + break; + } if ((ci->i_ceph_flags & CEPH_I_FLUSH) == 0 && time_before(jiffies, ci->i_hold_caps_max)) break; @@ -4252,6 +4265,8 @@ void ceph_check_delayed_caps(struct ceph_mds_client *mdsc) } } spin_unlock(&mdsc->cap_delay_lock); + + return delay; } /* diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c index 08c76bf57fb1..5f1bd7f9dce1 100644 --- a/fs/ceph/mds_client.c +++ b/fs/ceph/mds_client.c @@ -4518,11 +4518,12 @@ static void schedule_delayed(struct ceph_mds_client *mdsc, unsigned long delay) static void delayed_work(struct work_struct *work) { - int i; struct ceph_mds_client *mdsc = container_of(work, struct ceph_mds_client, delayed_work.work); + unsigned long delay; int renew_interval; int renew_caps; + int i; dout("mdsc delayed_work\n"); @@ -4562,7 +4563,7 @@ static void delayed_work(struct work_struct *work) } mutex_unlock(&mdsc->mutex); - ceph_check_delayed_caps(mdsc); + delay = ceph_check_delayed_caps(mdsc); ceph_queue_cap_reclaim_work(mdsc); @@ -4570,7 +4571,7 @@ static void delayed_work(struct work_struct *work) maybe_recover_session(mdsc); - schedule_delayed(mdsc, 0); + schedule_delayed(mdsc, delay); } int ceph_mdsc_init(struct ceph_fs_client *fsc) diff --git a/fs/ceph/super.h b/fs/ceph/super.h index 839e6b0239ee..3b5207c82767 100644 --- a/fs/ceph/super.h +++ b/fs/ceph/super.h @@ -1170,7 +1170,7 @@ extern void ceph_flush_snaps(struct ceph_inode_info *ci, extern bool __ceph_should_report_size(struct ceph_inode_info *ci); extern void ceph_check_caps(struct ceph_inode_info *ci, int flags, struct ceph_mds_session *session); -extern void ceph_check_delayed_caps(struct ceph_mds_client *mdsc); +extern unsigned long ceph_check_delayed_caps(struct ceph_mds_client *mdsc); extern void ceph_flush_dirty_caps(struct ceph_mds_client *mdsc); extern int ceph_drop_caps_for_unlink(struct inode *inode); extern int ceph_encode_inode_release(void **p, struct inode *inode,