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 A17B0C46467 for ; Fri, 20 Jan 2023 05:43:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230061AbjATFnz (ORCPT ); Fri, 20 Jan 2023 00:43:55 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53240 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229490AbjATFny (ORCPT ); Fri, 20 Jan 2023 00:43:54 -0500 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 75865A4 for ; Thu, 19 Jan 2023 21:43:51 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=7mSwR5Y0cDoaofS+SYCx3DCXdbofPPtO+Pvvj0DejHE=; b=AAtbPr4IEovx1NM4Zm0y0jAFzL Z8avf6ODlkJKEU4jPCCpel0dRxZSdJLgNT0I46T8QP3zGnudyX2VngP7EslecHtQdeKpP33HmXJ5Y lLDwlkomFaPm/jTrXxtyOddMPcYqSujrc05vdj/+L5djti7+lkuLa9byohNDIqqiE2vNimGYvix/K /Xbb8MKggofUU986rMpYfZ5CrFEz3j5AT36KRON41EPX0/+vYqp9umduGUQQFR+zO62tXPlHCJ5mz 9FOuHjU+NmzmB05o0DvJBrORXay5w5PTS4fcRl8GLPyQxW1FjLsHCE0rjIbGM5+IiqKoT4zccBuue UPTfDcPQ==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1pIkBk-001hds-Qp; Fri, 20 Jan 2023 05:43:44 +0000 Date: Fri, 20 Jan 2023 05:43:44 +0000 From: Matthew Wilcox To: Sidhartha Kumar Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, akpm@linux-foundation.org, songmuchun@bytedance.com, mike.kravetz@oracle.com, jhubbard@nvidia.com Subject: Re: [PATCH 2/9] mm/hugetlb: convert hugetlbfs_pagecache_present() to folios Message-ID: References: <20230119211446.54165-1-sidhartha.kumar@oracle.com> <20230119211446.54165-3-sidhartha.kumar@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230119211446.54165-3-sidhartha.kumar@oracle.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 19, 2023 at 01:14:39PM -0800, Sidhartha Kumar wrote: > +++ b/mm/hugetlb.c > @@ -5653,15 +5653,15 @@ static bool hugetlbfs_pagecache_present(struct hstate *h, > { > struct address_space *mapping; > pgoff_t idx; > - struct page *page; > + struct folio *folio; > > mapping = vma->vm_file->f_mapping; > idx = vma_hugecache_offset(h, vma, address); > > - page = find_get_page(mapping, idx); > - if (page) > - put_page(page); > - return page != NULL; > + folio = filemap_get_folio(mapping, idx); > + if (folio) > + folio_put(folio); > + return folio != NULL; > } Seems to me this function could be ... struct address_space *mapping = vma->vm_file->f_mapping; pgoff_t index = vma_hugecache_offset(h, vma, address); bool present; rcu_read_lock(); present = page_cache_next_miss(mapping, index, 1) != index; rcu_read_unlock(); return present; No need to get/drop a refcount on the folio. It's a bit similar to filemap_range_has_page(), but the API is wrong. Maybe there's room for a little refactoring here.