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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6AB69C61DA4 for ; Thu, 9 Feb 2023 15:34:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231342AbjBIPex (ORCPT ); Thu, 9 Feb 2023 10:34:53 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42450 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230470AbjBIPet (ORCPT ); Thu, 9 Feb 2023 10:34:49 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 12F5D5ACE9 for ; Thu, 9 Feb 2023 07:33:24 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1675956804; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: references:references; bh=0xpraGtvv+g3M3VM6y/rVH56xF8i4HGSirYhvlOx/70=; b=eFu4e4GvG0Uo7DgVB9GriV6abROJVR//AuPCtuhBgvAO5oaU+TzMaOfj9D9S4w2UA+WA05 YB+QCLZ2UhWicRIoHb5rrFsmtRSmutM1Et0/gZoWHGP0ViWs3aF+FnENcddF2dsnlqmOv2 huhVmeYeeujtsxognLot9EEyXDJKgd4= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-311-HYnLzgtyPPihlf6ibXjY4Q-1; Thu, 09 Feb 2023 10:33:19 -0500 X-MC-Unique: HYnLzgtyPPihlf6ibXjY4Q-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 963A72807D72; Thu, 9 Feb 2023 15:33:16 +0000 (UTC) Received: from tpad.localdomain (ovpn-112-3.gru2.redhat.com [10.97.112.3]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 6C910492B00; Thu, 9 Feb 2023 15:33:16 +0000 (UTC) Received: by tpad.localdomain (Postfix, from userid 1000) id 90B32403CC181; Thu, 9 Feb 2023 12:32:51 -0300 (-03) Message-ID: <20230209153204.929333982@redhat.com> User-Agent: quilt/0.67 Date: Thu, 09 Feb 2023 12:02:01 -0300 From: Marcelo Tosatti To: Christoph Lameter Cc: Aaron Tomlin , Frederic Weisbecker , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Marcelo Tosatti Subject: [PATCH v2 11/11] mm/vmstat: refresh stats remotely instead of via work item References: <20230209150150.380060673@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.9 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Refresh per-CPU stats remotely, instead of queueing work items, for the stat_refresh procfs method. This fixes sosreport hang (which uses vmstat_refresh) with spinning SCHED_FIFO process. Signed-off-by: Marcelo Tosatti Index: linux-2.6/mm/vmstat.c =================================================================== --- linux-2.6.orig/mm/vmstat.c +++ linux-2.6/mm/vmstat.c @@ -1865,11 +1865,21 @@ static DEFINE_PER_CPU(struct delayed_wor int sysctl_stat_interval __read_mostly = HZ; #ifdef CONFIG_PROC_FS + +#ifdef CONFIG_HAVE_CMPXCHG_LOCAL +static int refresh_all_vm_stats(void); +#else static void refresh_vm_stats(struct work_struct *work) { refresh_cpu_vm_stats(); } +static int refresh_all_vm_stats(void) +{ + return schedule_on_each_cpu(refresh_vm_stats); +} +#endif + int vmstat_refresh(struct ctl_table *table, int write, void *buffer, size_t *lenp, loff_t *ppos) { @@ -1889,7 +1899,7 @@ int vmstat_refresh(struct ctl_table *tab * transiently negative values, report an error here if any of * the stats is negative, so we know to go looking for imbalance. */ - err = schedule_on_each_cpu(refresh_vm_stats); + err = refresh_all_vm_stats(); if (err) return err; for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) { @@ -2009,7 +2019,7 @@ static DECLARE_DEFERRABLE_WORK(shepherd, #ifdef CONFIG_HAVE_CMPXCHG_LOCAL /* Flush counters remotely if CPU uses cmpxchg to update its per-CPU counters */ -static void vmstat_shepherd(struct work_struct *w) +static int refresh_all_vm_stats(void) { int cpu; @@ -2019,7 +2029,12 @@ static void vmstat_shepherd(struct work_ cond_resched(); } cpus_read_unlock(); + return 0; +} +static void vmstat_shepherd(struct work_struct *w) +{ + refresh_all_vm_stats(); schedule_delayed_work(&shepherd, round_jiffies_relative(sysctl_stat_interval)); }