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=-6.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 53AE5C433E1 for ; Fri, 21 Aug 2020 00:42:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 349DD20FC3 for ; Fri, 21 Aug 2020 00:42:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597970534; bh=VNwKEvb37hsvn1VTMYx2hDqpxy7g2QUUmUb4/3hoNVA=; h=Date:From:To:Subject:In-Reply-To:Reply-To:List-ID:From; b=yeO/ornujeMfOHIr5rjR1VbJ8U9yLWTcJ+6Ngv2ZQgnp+kCwOT6IASzjALGM8ONG3 8da5KpwAWts6mcpXR20QjjiJimOgRsvvGWywO1tHyHUv1aqXWK3czY95GJsvgnCtDz i3GFZHFWAIg9Pjiar5wnsRd/r8dNMRTZUsUKNgC4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727024AbgHUAmN (ORCPT ); Thu, 20 Aug 2020 20:42:13 -0400 Received: from mail.kernel.org ([198.145.29.99]:35328 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726938AbgHUAmG (ORCPT ); Thu, 20 Aug 2020 20:42:06 -0400 Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id CEA70207BB; Fri, 21 Aug 2020 00:42:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597970526; bh=VNwKEvb37hsvn1VTMYx2hDqpxy7g2QUUmUb4/3hoNVA=; h=Date:From:To:Subject:In-Reply-To:From; b=U0cwWhjxeL5oYwkOro+OZgJixZmkY5yldxoffTCTmZ8vuyDqJgZPpW/Y2RLTq7IqX iel6GQ4PDd/BhBnHzBGaF8DhtJ0N1vHUxc4cm4AApCOmxqcXFighHnkrTEWPXWUq2G XZ6neg0SBLMLkTLc7VQhRtOYZk/QZD0+uDpraFdY= Date: Thu, 20 Aug 2020 17:42:05 -0700 From: Andrew Morton To: akpm@linux-foundation.org, aneesh.kumar@linux.ibm.com, harish@linux.ibm.com, linux-mm@kvack.org, mm-commits@vger.kernel.org, stable@vger.kernel.org, torvalds@linux-foundation.org Subject: [patch 04/11] mm/vunmap: add cond_resched() in vunmap_pmd_range Message-ID: <20200821004205.P4PRreiY4%akpm@linux-foundation.org> In-Reply-To: <20200820174132.67fd4a7a9359048f807a533b@linux-foundation.org> User-Agent: s-nail v14.8.16 Sender: mm-commits-owner@vger.kernel.org Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org From: "Aneesh Kumar K.V" Subject: mm/vunmap: add cond_resched() in vunmap_pmd_range Like zap_pte_range add cond_resched so that we can avoid softlockups as reported below. On non-preemptible kernel with large I/O map region (like the one we get when using persistent memory with sector mode), an unmap of the namespace can report below softlockups. 22724.027334] watchdog: BUG: soft lockup - CPU#49 stuck for 23s! [ndctl:50777] NIP [c0000000000dc224] plpar_hcall+0x38/0x58 LR [c0000000000d8898] pSeries_lpar_hpte_invalidate+0x68/0xb0 Call Trace: [c0000004e87a7780] [c0000004fb197c00] 0xc0000004fb197c00 (unreliable) [c0000004e87a7810] [c00000000007f4e4] flush_hash_page+0x114/0x200 [c0000004e87a7890] [c0000000000833cc] hpte_need_flush+0x2dc/0x540 [c0000004e87a7950] [c0000000003f5798] vunmap_page_range+0x538/0x6f0 [c0000004e87a7a70] [c0000000003f76d0] free_unmap_vmap_area+0x30/0x70 [c0000004e87a7aa0] [c0000000003f7a6c] remove_vm_area+0xfc/0x140 [c0000004e87a7ad0] [c0000000003f7dd8] __vunmap+0x68/0x270 [c0000004e87a7b50] [c000000000079de4] __iounmap.part.0+0x34/0x60 [c0000004e87a7bb0] [c000000000376394] memunmap+0x54/0x70 [c0000004e87a7bd0] [c000000000881d7c] release_nodes+0x28c/0x300 [c0000004e87a7c40] [c00000000087a65c] device_release_driver_internal+0x16c/0x280 [c0000004e87a7c80] [c000000000876fc4] unbind_store+0x124/0x170 [c0000004e87a7cd0] [c000000000875be4] drv_attr_store+0x44/0x60 [c0000004e87a7cf0] [c00000000057c734] sysfs_kf_write+0x64/0x90 [c0000004e87a7d10] [c00000000057bc10] kernfs_fop_write+0x1b0/0x290 [c0000004e87a7d60] [c000000000488e6c] __vfs_write+0x3c/0x70 [c0000004e87a7d80] [c00000000048c868] vfs_write+0xd8/0x260 [c0000004e87a7dd0] [c00000000048ccac] ksys_write+0xdc/0x130 [c0000004e87a7e20] [c00000000000b588] system_call+0x5c/0x70 Link: http://lkml.kernel.org/r/20200807075933.310240-1-aneesh.kumar@linux.ibm.com Signed-off-by: Aneesh Kumar K.V Reported-by: Harish Sriram Reviewed-by: Andrew Morton Cc: Signed-off-by: Andrew Morton --- mm/vmalloc.c | 2 ++ 1 file changed, 2 insertions(+) --- a/mm/vmalloc.c~mm-vunmap-add-cond_resched-in-vunmap_pmd_range +++ a/mm/vmalloc.c @@ -104,6 +104,8 @@ static void vunmap_pmd_range(pud_t *pud, if (pmd_none_or_clear_bad(pmd)) continue; vunmap_pte_range(pmd, addr, next, mask); + + cond_resched(); } while (pmd++, addr = next, addr != end); } _