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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9E18AC43334 for ; Fri, 24 Jun 2022 08:52:37 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 27C066B0170; Fri, 24 Jun 2022 04:52:37 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 2039C6B0171; Fri, 24 Jun 2022 04:52:37 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0A5B48E0204; Fri, 24 Jun 2022 04:52:37 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id EB6EA6B0170 for ; Fri, 24 Jun 2022 04:52:36 -0400 (EDT) Received: from smtpin17.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay13.hostedemail.com (Postfix) with ESMTP id C36F96024C for ; Fri, 24 Jun 2022 08:52:36 +0000 (UTC) X-FDA: 79612513512.17.3C169DF Received: from out30-43.freemail.mail.aliyun.com (out30-43.freemail.mail.aliyun.com [115.124.30.43]) by imf06.hostedemail.com (Postfix) with ESMTP id 2872818002E for ; Fri, 24 Jun 2022 08:52:34 +0000 (UTC) X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R951e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018046059;MF=baolin.wang@linux.alibaba.com;NM=1;PH=DS;RN=5;SR=0;TI=SMTPD_---0VHGcxXq_1656060747; Received: from 30.97.49.29(mailfrom:baolin.wang@linux.alibaba.com fp:SMTPD_---0VHGcxXq_1656060747) by smtp.aliyun-inc.com; Fri, 24 Jun 2022 16:52:28 +0800 Message-ID: Date: Fri, 24 Jun 2022 16:52:34 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.10.0 Subject: Re: [RFC PATCH v2 2/3] mm: Add PUD level pagetable account To: Matthew Wilcox , Mike Rapoport Cc: akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: From: Baolin Wang In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1656060756; a=rsa-sha256; cv=none; b=oe5vQDLjBYCDiLLuTfILsCdKaPB6W9FYaAMjusmvybbqFgS0d317Ay8GYhXG7uHcZeo96H gF87MEokBBd3LcCk2EMQYsvt+NKh3VlP1C1pLwSIofajAcVBXC9XDfEtZbycUnOehS42jB SM4k/k1dz43rZvTqrZhvIy5jlWZRyiA= ARC-Authentication-Results: i=1; imf06.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=alibaba.com; spf=pass (imf06.hostedemail.com: domain of baolin.wang@linux.alibaba.com designates 115.124.30.43 as permitted sender) smtp.mailfrom=baolin.wang@linux.alibaba.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1656060756; h=from:from:sender: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=ApOczrdcyxWxPo2CGena+ZbmdZhXz0PWrGu8KADosNE=; b=e0CeVALbWAQOzo1f4M7rvJ6yhkALYfxBLoq5und/ZcSr+3PR21+kpI/C/rrPM3QkOOSJDV vY/DoxOZvl+idtAjnpLFSKwyd+tygnLTdTQkYJADzyXk3t7bKQk77NLzvoijxhWFFkJOsa 6GysPBoOMgFQ8buQJ5t/UIZUCdxrT3Q= X-Rspam-User: X-Stat-Signature: zkixu7oqgnj9htt6jysijwidy5iqa1ga X-Rspamd-Queue-Id: 2872818002E Authentication-Results: imf06.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=alibaba.com; spf=pass (imf06.hostedemail.com: domain of baolin.wang@linux.alibaba.com designates 115.124.30.43 as permitted sender) smtp.mailfrom=baolin.wang@linux.alibaba.com X-Rspamd-Server: rspam03 X-HE-Tag: 1656060754-254844 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 6/23/2022 9:28 PM, Matthew Wilcox wrote: > On Wed, Jun 22, 2022 at 09:38:30AM -0500, Mike Rapoport wrote: >> On Wed, Jun 22, 2022 at 04:58:53PM +0800, Baolin Wang wrote: >>> +++ b/arch/loongarch/include/asm/pgalloc.h >>> @@ -89,10 +89,15 @@ static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long address) >>> static inline pud_t *pud_alloc_one(struct mm_struct *mm, unsigned long address) >>> { >>> pud_t *pud; >>> + struct page *pg; >> >> struct page *page; >> >> looks better IMO. >> >>> + >>> + pg = alloc_pages(GFP_KERNEL & ~__GFP_HIGHMEM, PUD_ORDER); > > GFP_KERNEL does not include __GFP_HIGHMEM, so you can just use > GFP_KERNEL here. Yes. Thanks. > >>> + if (!pg) >>> + return NULL; >>> >>> - pud = (pud_t *) __get_free_pages(GFP_KERNEL, PUD_ORDER); >>> - if (pud) >>> - pud_init((unsigned long)pud, (unsigned long)invalid_pmd_table); >>> + pgtable_set_and_inc(pg); >>> + pud = (pud_t *)page_address(pg); >> >> I don't think __get_free_pages() should be replaced with alloc_pages() >> here, just call pgtable_set_and_inc() with virt_to_page(pud). > > I don't understand why you want that. Take a look at the implementation > of __get_free_pages(). Converting back to a struct page after calling > that seems like a real waste of time to me. IMO I have no strong preference. The code can be simpler with using __get_free_pages(), however like Matthew said it will add more conversion.