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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 B937DC433E8 for ; Mon, 22 Mar 2021 14:36:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 91C886197F for ; Mon, 22 Mar 2021 14:36:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230452AbhCVOgA (ORCPT ); Mon, 22 Mar 2021 10:36:00 -0400 Received: from mx2.suse.de ([195.135.220.15]:40490 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229771AbhCVOf1 (ORCPT ); Mon, 22 Mar 2021 10:35:27 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1616423726; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=ka7o8YzjuihRvqSaAHVBlNM4iZuzXnEWVNYaDHEt30s=; b=GsJ4VZ8ch9CqRDYUamqSvXfTADUchqiUp0ZGbfgY38XyC6G9M+qr/s72nDN88PGa3HNYR5 7K9yw3l9nCL2UkCkB2dK+T9geEcMlPuaheGoomXCXjb6umrBmsz6YGbL4+0+Qm81qfsAWY 9Hw3Jxm9ZX6Z1dMYd20+UqMQKMlqksc= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id EB4A5AC1F; Mon, 22 Mar 2021 14:35:25 +0000 (UTC) Date: Mon, 22 Mar 2021 15:35:25 +0100 From: Michal Hocko To: Mike Kravetz Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Shakeel Butt , Oscar Salvador , David Hildenbrand , Muchun Song , David Rientjes , Miaohe Lin , Peter Zijlstra , Matthew Wilcox , HORIGUCHI NAOYA , "Aneesh Kumar K . V" , Waiman Long , Peter Xu , Mina Almasry , Andrew Morton Subject: Re: [RFC PATCH 6/8] hugetlb: make free_huge_page irq safe Message-ID: References: <20210319224209.150047-1-mike.kravetz@oracle.com> <20210319224209.150047-7-mike.kravetz@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210319224209.150047-7-mike.kravetz@oracle.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri 19-03-21 15:42:07, Mike Kravetz wrote: > Commit c77c0a8ac4c5 ("mm/hugetlb: defer freeing of huge pages if in > non-task context") was added to address the issue of free_huge_page > being called from irq context. That commit hands off free_huge_page > processing to a workqueue if !in_task. However, as seen in [1] this > does not cover all cases. Instead, make the locks taken in the > free_huge_page irq safe. > > This patch does the following: > - Make hugetlb_lock irq safe. This is mostly a simple process of > changing spin_*lock calls to spin_*lock_irq* calls. > - Make subpool lock irq safe in a similar manner. > - Revert the !in_task check and workqueue handoff. This is not sufficient (and 0day bot has captured that already). You cannot call update_and_free_page from the same context. -- Michal Hocko SUSE Labs