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=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 CC531C43460 for ; Mon, 12 Apr 2021 10:21:46 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 5D02F61357 for ; Mon, 12 Apr 2021 10:21:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5D02F61357 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 4C1A16B0036; Mon, 12 Apr 2021 06:21:45 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 44B6D6B006C; Mon, 12 Apr 2021 06:21:45 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 29E126B006E; Mon, 12 Apr 2021 06:21:45 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0205.hostedemail.com [216.40.44.205]) by kanga.kvack.org (Postfix) with ESMTP id 067EF6B0036 for ; Mon, 12 Apr 2021 06:21:45 -0400 (EDT) Received: from smtpin11.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 9D1E81802A366 for ; Mon, 12 Apr 2021 10:21:44 +0000 (UTC) X-FDA: 78023323728.11.4F357AB Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf25.hostedemail.com (Postfix) with ESMTP id D23FD600010B for ; Mon, 12 Apr 2021 10:21:41 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id A9E95AFE2; Mon, 12 Apr 2021 10:21:42 +0000 (UTC) Subject: Re: [PATCH 2/9] mm/page_alloc: Add a bulk page allocator To: Mel Gorman , Andrew Morton Cc: Chuck Lever , Jesper Dangaard Brouer , Christoph Hellwig , Alexander Duyck , Matthew Wilcox , Ilias Apalodimas , LKML , Linux-Net , Linux-MM , Linux-NFS References: <20210325114228.27719-1-mgorman@techsingularity.net> <20210325114228.27719-3-mgorman@techsingularity.net> From: Vlastimil Babka Message-ID: <28729c76-4e09-f860-0db1-9c79c8220683@suse.cz> Date: Mon, 12 Apr 2021 12:21:42 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.1 MIME-Version: 1.0 In-Reply-To: <20210325114228.27719-3-mgorman@techsingularity.net> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: D23FD600010B X-Stat-Signature: x97ug9a5aq4hom7h9waygdmhbt58zz6f Received-SPF: none (suse.cz>: No applicable sender policy available) receiver=imf25; identity=mailfrom; envelope-from=""; helo=mx2.suse.de; client-ip=195.135.220.15 X-HE-DKIM-Result: none/none X-HE-Tag: 1618222901-355163 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 3/25/21 12:42 PM, Mel Gorman wrote: > This patch adds a new page allocator interface via alloc_pages_bulk, > and __alloc_pages_bulk_nodemask. A caller requests a number of pages > to be allocated and added to a list. > > The API is not guaranteed to return the requested number of pages and > may fail if the preferred allocation zone has limited free memory, the > cpuset changes during the allocation or page debugging decides to fail > an allocation. It's up to the caller to request more pages in batch > if necessary. > > Note that this implementation is not very efficient and could be improved > but it would require refactoring. The intent is to make it available early > to determine what semantics are required by different callers. Once the > full semantics are nailed down, it can be refactored. > > Signed-off-by: Mel Gorman > Acked-by: Vlastimil Babka > --- > include/linux/gfp.h | 11 +++++ > mm/page_alloc.c | 118 ++++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 129 insertions(+) > > diff --git a/include/linux/gfp.h b/include/linux/gfp.h > index 0a88f84b08f4..4a304fd39916 100644 > --- a/include/linux/gfp.h > +++ b/include/linux/gfp.h > @@ -518,6 +518,17 @@ static inline int arch_make_page_accessible(struct page *page) > struct page *__alloc_pages(gfp_t gfp, unsigned int order, int preferred_nid, > nodemask_t *nodemask); > > +int __alloc_pages_bulk(gfp_t gfp, int preferred_nid, > + nodemask_t *nodemask, int nr_pages, > + struct list_head *list); > + > +/* Bulk allocate order-0 pages */ > +static inline unsigned long > +alloc_pages_bulk(gfp_t gfp, unsigned long nr_pages, struct list_head *list) > +{ > + return __alloc_pages_bulk(gfp, numa_mem_id(), NULL, nr_pages, list); > +} > + > /* > * Allocate pages, preferring the node given as nid. The node must be valid and > * online. For more general interface, see alloc_pages_node(). > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 8a3e13277e22..eb547470a7e4 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -4965,6 +4965,124 @@ static inline bool prepare_alloc_pages(gfp_t gfp_mask, unsigned int order, > return true; > } > > +/* > + * __alloc_pages_bulk - Allocate a number of order-0 pages to a list > + * @gfp: GFP flags for the allocation > + * @preferred_nid: The preferred NUMA node ID to allocate from > + * @nodemask: Set of nodes to allocate from, may be NULL > + * @nr_pages: The number of pages desired on the list > + * @page_list: List to store the allocated pages > + * > + * This is a batched version of the page allocator that attempts to > + * allocate nr_pages quickly and add them to a list. > + * > + * Returns the number of pages on the list. > + */ > +int __alloc_pages_bulk(gfp_t gfp, int preferred_nid, > + nodemask_t *nodemask, int nr_pages, > + struct list_head *page_list) > +{ > + struct page *page; > + unsigned long flags; > + struct zone *zone; > + struct zoneref *z; > + struct per_cpu_pages *pcp; > + struct list_head *pcp_list; > + struct alloc_context ac; > + gfp_t alloc_gfp; > + unsigned int alloc_flags; Was going to complain that this is not set to ALLOC_WMARK_LOW. Must be faster next time... > + int allocated = 0; > + > + if (WARN_ON_ONCE(nr_pages <= 0)) > + return 0; > + > + /* Use the single page allocator for one page. */ > + if (nr_pages == 1) > + goto failed; > + > + /* May set ALLOC_NOFRAGMENT, fragmentation will return 1 page. */ I don't understand this comment. Only alloc_flags_nofragment() sets this flag and we don't use it here? > + gfp &= gfp_allowed_mask; > + alloc_gfp = gfp; > + if (!prepare_alloc_pages(gfp, 0, preferred_nid, nodemask, &ac, &alloc_gfp, &alloc_flags)) > + return 0; > + gfp = alloc_gfp; > + > + /* Find an allowed local zone that meets the high watermark. */ Should it say "low watermark"? Vlastimil