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=-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 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 8AA08C433DB for ; Wed, 17 Mar 2021 14:27:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2B00864F4D for ; Wed, 17 Mar 2021 14:27:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230516AbhCQO1O (ORCPT ); Wed, 17 Mar 2021 10:27:14 -0400 Received: from mx2.suse.de ([195.135.220.15]:45876 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231854AbhCQO0v (ORCPT ); Wed, 17 Mar 2021 10:26:51 -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=1615991210; 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=ExqOnSIQiOaoWEYvwSez5xa/aq9YCVfc0lV3CL7i3iQ=; b=lFvXnQ53BOyeeG3ZK3sWgW7KPIFDixu0NEYiqeDN5ysIU0KPLSc4c83s0m3OkkjkRQxnBA Oz2ZTPv+COXa/ooVO0HYH3Nuqu6K6BO/fhzMWUPV/dU3qacvDfs0HxIKJn+o36Gb3pj+1H yrYwvUbenlh32OItwJOvu6FNnipE1iE= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id BF1A5AD74; Wed, 17 Mar 2021 14:26:50 +0000 (UTC) Date: Wed, 17 Mar 2021 15:26:50 +0100 From: Michal Hocko To: Oscar Salvador Cc: Andrew Morton , Vlastimil Babka , David Hildenbrand , Muchun Song , Mike Kravetz , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v5 4/5] mm: Make alloc_contig_range handle in-use hugetlb pages Message-ID: References: <20210317111251.17808-1-osalvador@suse.de> <20210317111251.17808-5-osalvador@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210317111251.17808-5-osalvador@suse.de> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 17-03-21 12:12:50, Oscar Salvador wrote: > alloc_contig_range() will fail if it finds a HugeTLB page within the range, > without a chance to handle them. Since HugeTLB pages can be migrated as any > LRU or Movable page, it does not make sense to bail out without trying. > Enable the interface to recognize in-use HugeTLB pages so we can migrate > them, and have much better chances to succeed the call. > > Signed-off-by: Oscar Salvador > Reviewed-by: Mike Kravetz Acked-by: Michal Hocko I am still not entirely happy about this > @@ -2347,7 +2351,19 @@ int isolate_or_dissolve_huge_page(struct page *page) > if (hstate_is_gigantic(h)) > return -ENOMEM; > > - return alloc_and_dissolve_huge_page(h, head); > +retry: > + if (page_count(head) && isolate_huge_page(head, list)) { > + ret = 0; > + } else if (!page_count(head)) { > + ret = alloc_and_dissolve_huge_page(h, head); > + > + if (ret == -EBUSY && try_again) { > + try_again = false; > + goto retry; > + } > + } > + > + return ret; > } it would be imho better to retry inside alloc_and_dissolve_huge_page because it already has its retry logic implemented. But not something I will insist on. -- Michal Hocko SUSE Labs