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=-6.0 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,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 EABE6C07E95 for ; Sat, 10 Jul 2021 21:10:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C7AE761186 for ; Sat, 10 Jul 2021 21:10:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229714AbhGJVNN (ORCPT ); Sat, 10 Jul 2021 17:13:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42366 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229515AbhGJVNM (ORCPT ); Sat, 10 Jul 2021 17:13:12 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C2356C0613DD for ; Sat, 10 Jul 2021 14:10:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=3Fv3JaRsdV1s9RLb16qwGkvG9CqOP8qJx48U5nNcWB4=; b=Yp8zWtcy26W2BtPEMT2CjH4Gke Xn0rxqYx1pvRTOyswBT7QbQVhezMkXCivxY/pAHYdNfrYrXGkhi1bX6tAENIzIYRHlyqu/BhHNQdZ tDNNw6xlT1+HwBxBXpOclx21UHLponACB9rhAXi8Ed7DYAk/f/nlSrMW/VG4E7IBkwo6XFzPR15o8 ueSy/D43aRuxoGnBRt9q8nx6kGuIVvUq2lY4l42PlEIZgfQuWTSa/RwP6oEO57EeikrTk39qtHCrT Kndgc+qQP15tp+fsINoHMvLfqHkMJTO7u2bWVNeTeTgdUNjMa0xR1SdgHvYAax+G2+P5j/GL0NRFN 4itYNJYA==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1m2KEd-00FlRk-Rz; Sat, 10 Jul 2021 21:10:06 +0000 Date: Sat, 10 Jul 2021 22:10:03 +0100 From: Matthew Wilcox To: Andrew Morton Cc: qiang.zhang@windriver.com, mgorman@techsingularity.net, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm/page_alloc: avoid hard lockups in __alloc_pages_bulk() Message-ID: References: <20210710112929.232268-1-qiang.zhang@windriver.com> <20210710114613.0db3ac139a7b3102a6ca3ad4@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210710114613.0db3ac139a7b3102a6ca3ad4@linux-foundation.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Jul 10, 2021 at 11:46:13AM -0700, Andrew Morton wrote: > On Sat, 10 Jul 2021 19:29:29 +0800 qiang.zhang@windriver.com wrote: > > > From: Zqiang > > > > The __alloc_pages_bulk() mainly used for batch allocation of > > order-0 pages, in the case of holding pagesets.lock, if too > > many pages are required, maybe trigger hard lockup watchdog. > > Ouch. Has this been observed in testing? If so, can you please share > the kernel debug output from that event? This should be fixed in the caller by asking for fewer pages. The NFS and vmalloc cases have already been fixed for this.