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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1D5A2C433EF for ; Fri, 22 Apr 2022 11:48:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1447136AbiDVLu7 (ORCPT ); Fri, 22 Apr 2022 07:50:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51642 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1380235AbiDVLu6 (ORCPT ); Fri, 22 Apr 2022 07:50:58 -0400 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 93E9D41FAA for ; Fri, 22 Apr 2022 04:48:04 -0700 (PDT) Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out2.suse.de (Postfix) with ESMTP id 4D8EB1F388; Fri, 22 Apr 2022 11:48:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1650628083; 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=NgFv0sENXvVUOYbTHjKFVYGjlYg+9hQjDCMXuvJ5JfM=; b=DwpVMrBR1w5g+T+TbhLjBoR3qPund5PzP/4AYuuLA6MgeeU5LvmArftpPqGysD33WsvxUS eMx5ACD1yTmnJq5WFlmqcQEUa6jjb8AXvjjlUzbU2xGmOyax5Dxest9GcvrDttW5KV5Rfc JsfqvZCHLNOSJBrnYTX3bJWJRGcftzs= Received: from suse.cz (unknown [10.100.201.86]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by relay2.suse.de (Postfix) with ESMTPS id E74642C145; Fri, 22 Apr 2022 11:48:01 +0000 (UTC) Date: Fri, 22 Apr 2022 13:48:00 +0200 From: Michal Hocko To: Miaohe Lin Cc: akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm/mempolicy: clean up the code logic in queue_pages_pte_range Message-ID: References: <20220419122234.45083-1-linmiaohe@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220419122234.45083-1-linmiaohe@huawei.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue 19-04-22 20:22:34, Miaohe Lin wrote: > Since commit e5947d23edd8 ("mm: mempolicy: don't have to split pmd for > huge zero page"), THP is never splited in queue_pages_pmd. Thus 2 is > never returned now. We can remove such unnecessary ret != 2 check and > clean up the relevant comment. Minor improvements in readability. > > Signed-off-by: Miaohe Lin Acked-by: Michal Hocko Thanks! > --- > mm/mempolicy.c | 12 +++--------- > 1 file changed, 3 insertions(+), 9 deletions(-) > > diff --git a/mm/mempolicy.c b/mm/mempolicy.c > index 75a8b247f631..3934476fb708 100644 > --- a/mm/mempolicy.c > +++ b/mm/mempolicy.c > @@ -441,12 +441,11 @@ static inline bool queue_pages_required(struct page *page, > } > > /* > - * queue_pages_pmd() has four possible return values: > + * queue_pages_pmd() has three possible return values: > * 0 - pages are placed on the right node or queued successfully, or > * special page is met, i.e. huge zero page. > * 1 - there is unmovable page, and MPOL_MF_MOVE* & MPOL_MF_STRICT were > * specified. > - * 2 - THP was split. > * -EIO - is migration entry or only MPOL_MF_STRICT was specified and an > * existing page was already on a node that does not follow the > * policy. > @@ -508,18 +507,13 @@ static int queue_pages_pte_range(pmd_t *pmd, unsigned long addr, > struct page *page; > struct queue_pages *qp = walk->private; > unsigned long flags = qp->flags; > - int ret; > bool has_unmovable = false; > pte_t *pte, *mapped_pte; > spinlock_t *ptl; > > ptl = pmd_trans_huge_lock(pmd, vma); > - if (ptl) { > - ret = queue_pages_pmd(pmd, ptl, addr, end, walk); > - if (ret != 2) > - return ret; > - } > - /* THP was split, fall through to pte walk */ > + if (ptl) > + return queue_pages_pmd(pmd, ptl, addr, end, walk); > > if (pmd_trans_unstable(pmd)) > return 0; > -- > 2.23.0 -- Michal Hocko SUSE Labs