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=-10.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY 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 05E10C433E6 for ; Tue, 1 Sep 2020 01:42:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E011220707 for ; Tue, 1 Sep 2020 01:42:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726102AbgIABmI (ORCPT ); Mon, 31 Aug 2020 21:42:08 -0400 Received: from out30-44.freemail.mail.aliyun.com ([115.124.30.44]:57547 "EHLO out30-44.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725941AbgIABmI (ORCPT ); Mon, 31 Aug 2020 21:42:08 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R511e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e07488;MF=richard.weiyang@linux.alibaba.com;NM=1;PH=DS;RN=6;SR=0;TI=SMTPD_---0U7Tly0l_1598924523; Received: from localhost(mailfrom:richard.weiyang@linux.alibaba.com fp:SMTPD_---0U7Tly0l_1598924523) by smtp.aliyun-inc.com(127.0.0.1); Tue, 01 Sep 2020 09:42:04 +0800 Date: Tue, 1 Sep 2020 09:42:03 +0800 From: Wei Yang To: Mike Kravetz Cc: Wei Yang , akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, bhe@redhat.com Subject: Re: [Patch v3 7/7] mm/hugetlb: take the free hpage during the iteration directly Message-ID: <20200901014203.GA29343@L-31X9LVDL-1304.local> Reply-To: Wei Yang References: <20200831022351.20916-1-richard.weiyang@linux.alibaba.com> <20200831022351.20916-8-richard.weiyang@linux.alibaba.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 31, 2020 at 04:06:54PM -0700, Mike Kravetz wrote: >On 8/30/20 7:23 PM, Wei Yang wrote: >> Function dequeue_huge_page_node_exact() iterates the free list and >> return the first valid free hpage. >> >> Instead of break and check the loop variant, we could return in the loop >> directly. This could reduce some redundant check. >> >> Signed-off-by: Wei Yang >> --- >> mm/hugetlb.c | 20 ++++++++------------ >> 1 file changed, 8 insertions(+), 12 deletions(-) >> >> diff --git a/mm/hugetlb.c b/mm/hugetlb.c >> index 7b3357c1dcec..709be7ab65af 100644 >> --- a/mm/hugetlb.c >> +++ b/mm/hugetlb.c >> @@ -1040,21 +1040,17 @@ static struct page *dequeue_huge_page_node_exact(struct hstate *h, int nid) >> if (nocma && is_migrate_cma_page(page)) >> continue; >> >> - if (!PageHWPoison(page)) >> + if (PageHWPoison(page)) >> break; > >Previously, when encountering a PageHWPoison(page) the loop would continue >and check the next page in the list. It now breaks the loop and returns >NULL. Is not this a change in behavior? Perhaps you want to change that >break to a continue. Or, restructure in some other way. Shame on me. You are right. I should change it to continue. Andrew, Sorry for the inconvenience. >-- >Mike Kravetz > >> + >> + list_move(&page->lru, &h->hugepage_activelist); >> + set_page_refcounted(page); >> + h->free_huge_pages--; >> + h->free_huge_pages_node[nid]--; >> + return page; >> } >> >> - /* >> - * if 'non-isolated free hugepage' not found on the list, >> - * the allocation fails. >> - */ >> - if (&h->hugepage_freelists[nid] == &page->lru) >> - return NULL; >> - list_move(&page->lru, &h->hugepage_activelist); >> - set_page_refcounted(page); >> - h->free_huge_pages--; >> - h->free_huge_pages_node[nid]--; >> - return page; >> + return NULL; >> } >> >> static struct page *dequeue_huge_page_nodemask(struct hstate *h, gfp_t gfp_mask, int nid, >> -- Wei Yang Help you, Help me