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 B8E39EE01FF for ; Wed, 13 Sep 2023 17:56:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231630AbjIMR4v (ORCPT ); Wed, 13 Sep 2023 13:56:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37594 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229468AbjIMR4t (ORCPT ); Wed, 13 Sep 2023 13:56:49 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7E01419AF; Wed, 13 Sep 2023 10:56:45 -0700 (PDT) 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=j6TR8SsaVNvXoZXM4p/X/ufLRTS7CLck9GylhLcr1pc=; b=QeAR9aJryEAZJrtFCudhXKDxSz H5VXRj/oxyS2qFjva1YVKSyydJvO/mb6S6E89Zcl5M0wGSgx0a/Mr9Aes8l0gqhFXtfdLqSxBPpLz pY4zFybsnQ7KsMfP2uHON558nFCdGHpl53X5MKFQbDywZIytry2FDPvi/ynDYoqf+c3l6USNb4iiK X//XRYh2fRmoJF3Nl2BfH/LQQAoIaxF5skuRyXOVR5oW9cR2F4hGw/zdue20NPVABOZD1uhDUGNxx RgOlO3y1xYLFGel/VHJRUyWj3XDXt/jcrbC0VM9bfXWH80InfSRLuaHuZQ1Sjr7g9eyln5CaMyWyY pUii1Ipw==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1qgU5s-00FIt1-Ok; Wed, 13 Sep 2023 17:56:04 +0000 Date: Wed, 13 Sep 2023 18:56:04 +0100 From: Matthew Wilcox To: Sourav Panda Cc: corbet@lwn.net, gregkh@linuxfoundation.org, rafael@kernel.org, akpm@linux-foundation.org, mike.kravetz@oracle.com, muchun.song@linux.dev, rppt@kernel.org, david@redhat.com, rdunlap@infradead.org, chenlinxuan@uniontech.com, yang.yang29@zte.com.cn, tomas.mudrunka@gmail.com, bhelgaas@google.com, ivan@cloudflare.com, pasha.tatashin@soleen.com, yosryahmed@google.com, hannes@cmpxchg.org, shakeelb@google.com, kirill.shutemov@linux.intel.com, wangkefeng.wang@huawei.com, adobriyan@gmail.com, vbabka@suse.cz, Liam.Howlett@oracle.com, surenb@google.com, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH v1 1/1] mm: report per-page metadata information Message-ID: References: <20230913173000.4016218-1-souravpanda@google.com> <20230913173000.4016218-2-souravpanda@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230913173000.4016218-2-souravpanda@google.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Sep 13, 2023 at 10:30:00AM -0700, Sourav Panda wrote: > @@ -387,8 +390,12 @@ static int alloc_vmemmap_page_list(unsigned long start, unsigned long end, > > while (nr_pages--) { > page = alloc_pages_node(nid, gfp_mask, 0); > - if (!page) > + if (!page) { > goto out; > + } else { > + __mod_node_page_state(NODE_DATA(page_to_nid(page)), > + NR_PAGE_METADATA, 1); > + } > list_add_tail(&page->lru, list); What a strange way of writing this. Why not simply: if (!page) goto out; + __mod_node_page_state(NODE_DATA(page_to_nid(page)), + NR_PAGE_METADATA, 1); list_add_tail(&page->lru, list); > @@ -314,6 +319,10 @@ static void free_page_ext(void *addr) > BUG_ON(PageReserved(page)); > kmemleak_free(addr); > free_pages_exact(addr, table_size); > + > + __mod_node_page_state(NODE_DATA(page_to_nid(page)), NR_PAGE_METADATA, > + (long)-1 * (PAGE_ALIGN(table_size) >> PAGE_SHIFT)); Why not spell that as "-1L"? And while I'm asking questions, why NODE_DATA(page_to_nid(page)) instead of page_pgdat(page)? > @@ -2274,4 +2275,24 @@ static int __init extfrag_debug_init(void) > } > > module_init(extfrag_debug_init); > + > +// Page metadata size (struct page and page_ext) in pages Don't use // comments. > +void __init writeout_early_perpage_metadata(void) "writeout" is something swap does. I'm sure this has a better name, though I can't think what it might be. > +{ > + int nid; > + struct pglist_data *pgdat; > + > + for_each_online_pgdat(pgdat) { > + nid = pgdat->node_id; > + __mod_node_page_state(NODE_DATA(nid), NR_PAGE_METADATA, > + early_perpage_metadata[nid]); > + } > +} > #endif > -- > 2.42.0.283.g2d96d420d3-goog >