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,DKIMWL_WL_HIGH, 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 CA25FC433E6 for ; Mon, 15 Feb 2021 16:16:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9B11364DF0 for ; Mon, 15 Feb 2021 16:16:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230383AbhBOQP7 (ORCPT ); Mon, 15 Feb 2021 11:15:59 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:29896 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231948AbhBOQMR (ORCPT ); Mon, 15 Feb 2021 11:12:17 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1613405450; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=wGz5aMZ2jUE7VsZQ0p6DHdAUwcF8yoK7x2FH4KaV5ws=; b=NKYlTdy8uzaenOkMO2jRgxysmPl2yrK9ctqnsV3+EALcZtFKgyVuu7mLaoFDpXYmZGoPzt MeeVMSjaOg7dxoTV7Gffd93nPgBu6V2kcmK5qQ126yFKWEKC4x6ou9qhSsNrvBgAPidnWr hfFhm9/PeEl2Lv6zhhGm/yI8ZQq4q7g= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-286-QWwqF1qcM4as0fDR0HtNpg-1; Mon, 15 Feb 2021 11:10:46 -0500 X-MC-Unique: QWwqF1qcM4as0fDR0HtNpg-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 0B02B801962; Mon, 15 Feb 2021 16:10:45 +0000 (UTC) Received: from carbon (unknown [10.36.110.45]) by smtp.corp.redhat.com (Postfix) with ESMTP id 498B45D9C0; Mon, 15 Feb 2021 16:10:39 +0000 (UTC) Date: Mon, 15 Feb 2021 17:10:38 +0100 From: Jesper Dangaard Brouer To: Mel Gorman Cc: Chuck Lever , Mel Gorman , Linux NFS Mailing List , "linux-mm@kvack.org" , Jakub Kicinski , brouer@redhat.com Subject: Re: alloc_pages_bulk() Message-ID: <20210215171038.42f62438@carbon> In-Reply-To: <20210215120056.GD3697@techsingularity.net> References: <2A0C36E7-8CB0-486F-A8DB-463CA28C5C5D@oracle.com> <20210209113108.1ca16cfa@carbon> <20210210084155.GA3697@techsingularity.net> <20210210124103.56ed1e95@carbon> <20210210130705.GC3629@suse.de> <20210211091235.GC3697@techsingularity.net> <20210211132628.1fe4f10b@carbon> <20210215120056.GD3697@techsingularity.net> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org On Mon, 15 Feb 2021 12:00:56 +0000 Mel Gorman wrote: > On Thu, Feb 11, 2021 at 01:26:28PM +0100, Jesper Dangaard Brouer wrote: [...] > > > I also suggest the API can return less pages than requested. Because I > > want to to "exit"/return if it need to go into an expensive code path > > (like buddy allocator or compaction). I'm assuming we have a flags to > > give us this behavior (via gfp_flags or alloc_flags)? > > > > The API returns the number of pages returned on a list so policies > around how aggressive it should be allocating the requested number of > pages could be adjusted without changing the API. Passing in policy > requests via gfp_flags may be problematic as most (all?) bits are > already used. Well, I was just thinking that I would use GFP_ATOMIC instead of GFP_KERNEL to "communicate" that I don't want this call to take too long (like sleeping). I'm not requesting any fancy policy :-) For page_pool use case we use (GFP_ATOMIC | __GFP_NOWARN) flags. static inline struct page *page_pool_dev_alloc_pages(struct page_pool *pool) { gfp_t gfp = (GFP_ATOMIC | __GFP_NOWARN); return page_pool_alloc_pages(pool, gfp); } -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer