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=-11.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 3757DC433E1 for ; Tue, 14 Jul 2020 09:13:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 192D92145D for ; Tue, 14 Jul 2020 09:13:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726851AbgGNJNQ (ORCPT ); Tue, 14 Jul 2020 05:13:16 -0400 Received: from mx2.suse.de ([195.135.220.15]:56228 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725833AbgGNJNQ (ORCPT ); Tue, 14 Jul 2020 05:13:16 -0400 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 1BAC0AAC7; Tue, 14 Jul 2020 09:13:17 +0000 (UTC) Subject: Re: [PATCH] mm/hugetlb: hide nr_nodes in the internal of for_each_node_mask_to_[alloc|free] To: Wei Yang , mike.kravetz@oracle.com, akpm@linux-foundation.org Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20200714073404.84863-1-richard.weiyang@linux.alibaba.com> From: Vlastimil Babka Message-ID: Date: Tue, 14 Jul 2020 11:13:14 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20200714073404.84863-1-richard.weiyang@linux.alibaba.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 7/14/20 9:34 AM, Wei Yang wrote: > The second parameter of for_each_node_mask_to_[alloc|free] is a loop > variant, which is not used outside of loop iteration. > > Let's hide this. > > Signed-off-by: Wei Yang > --- > mm/hugetlb.c | 38 ++++++++++++++++++++------------------ > 1 file changed, 20 insertions(+), 18 deletions(-) > > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > index 57ece74e3aae..9c3d15fb317e 100644 > --- a/mm/hugetlb.c > +++ b/mm/hugetlb.c > @@ -1196,17 +1196,19 @@ static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed) > return nid; > } > > -#define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask) \ > - for (nr_nodes = nodes_weight(*mask); \ > - nr_nodes > 0 && \ > +#define for_each_node_mask_to_alloc(hs, node, mask) \ > + int __nr_nodes; \ > + for (__nr_nodes = nodes_weight(*mask); \ The problem with this is that if I use the macro twice in the same block, this will redefine __nr_nodes and fail to compile, no? In that case it's better to avoid setting up this trap, IMHO. > + __nr_nodes > 0 && \ > ((node = hstate_next_node_to_alloc(hs, mask)) || 1); \ > - nr_nodes--) > + __nr_nodes--) > > -#define for_each_node_mask_to_free(hs, nr_nodes, node, mask) \ > - for (nr_nodes = nodes_weight(*mask); \ > - nr_nodes > 0 && \ > +#define for_each_node_mask_to_free(hs, node, mask) \ > + int __nr_nodes; \ > + for (__nr_nodes = nodes_weight(*mask); \ > + __nr_nodes > 0 && \ > ((node = hstate_next_node_to_free(hs, mask)) || 1); \ > - nr_nodes--) > + __nr_nodes--) > > #ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE > static void destroy_compound_gigantic_page(struct page *page, > @@ -1403,7 +1405,7 @@ static void __free_huge_page(struct page *page) > * reservation. If the page was associated with a subpool, there > * would have been a page reserved in the subpool before allocation > * via hugepage_subpool_get_pages(). Since we are 'restoring' the > - * reservtion, do not call hugepage_subpool_put_pages() as this will > + * reservation, do not call hugepage_subpool_put_pages() as this will > * remove the reserved page from the subpool. > */ > if (!restore_reserve) { > @@ -1760,10 +1762,10 @@ static int alloc_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed, > nodemask_t *node_alloc_noretry) > { > struct page *page; > - int nr_nodes, node; > + int node; > gfp_t gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE; > > - for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) { > + for_each_node_mask_to_alloc(h, node, nodes_allowed) { > page = alloc_fresh_huge_page(h, gfp_mask, node, nodes_allowed, > node_alloc_noretry); > if (page) > @@ -1787,10 +1789,10 @@ static int alloc_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed, > static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed, > bool acct_surplus) > { > - int nr_nodes, node; > + int node; > int ret = 0; > > - for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) { > + for_each_node_mask_to_free(h, node, nodes_allowed) { > /* > * If we're returning unused surplus pages, only examine > * nodes with surplus pages. > @@ -2481,9 +2483,9 @@ int alloc_bootmem_huge_page(struct hstate *h) > int __alloc_bootmem_huge_page(struct hstate *h) > { > struct huge_bootmem_page *m; > - int nr_nodes, node; > + int node; > > - for_each_node_mask_to_alloc(h, nr_nodes, node, &node_states[N_MEMORY]) { > + for_each_node_mask_to_alloc(h, node, &node_states[N_MEMORY]) { > void *addr; > > addr = memblock_alloc_try_nid_raw( > @@ -2662,17 +2664,17 @@ static inline void try_to_free_low(struct hstate *h, unsigned long count, > static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed, > int delta) > { > - int nr_nodes, node; > + int node; > > VM_BUG_ON(delta != -1 && delta != 1); > > if (delta < 0) { > - for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) { > + for_each_node_mask_to_alloc(h, node, nodes_allowed) { > if (h->surplus_huge_pages_node[node]) > goto found; > } > } else { > - for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) { > + for_each_node_mask_to_free(h, node, nodes_allowed) { > if (h->surplus_huge_pages_node[node] < > h->nr_huge_pages_node[node]) > goto found; >