From nobody Sun Feb 8 17:43:09 2026 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0FD00172BB3 for ; Mon, 25 Mar 2024 14:57:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711378662; cv=none; b=oIDe2p2Jz3Bl2rinGiWUG19A0de9yYs2aMZNopaVt1NbcQdR5xWRvxYu+YSB7wGS9M0jGZLAdjgbFlPdF26m1A4wNeFUhERGDcFUG16a2FgPAAFhHjbXkCpRMR7KaJ0R5QkiH5VM3rHmS8Kly1R8qIu2V68f24tURtHCG8M/jTE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711378662; c=relaxed/simple; bh=/T0vBiojUllP7pC9C+2rZRG/biMsPIykoiuiXxoG924=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-type; b=eKzPJQxNJD0aW/RGYpgNOgeUj6bDnWpphLdgMfHOTNqWKQDVWLmo3Cl+6EA12QeamtxnbeY7+1cjk5nowoKNOe5eHJApbWpbK9WlSrKXk8vZq724OPk+JNpT0WjU4YQCcSD8COoQ3KCeDiM9gwvqFDEgGEQrIPOnKZ3u4H9JBI8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=GVPaaVJq; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="GVPaaVJq" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1711378660; h=from:from: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=5tjcWip8Jh3x6TpRu3FCVwM3jxp/f+pF40FWxJhLLRM=; b=GVPaaVJqcmQSv8r2ReNTkvsmjvpuQJNb6P+zUyaMMlaI1A3uPOW5BVUwhGIWSvuvbdNZvf oIJbk8HvUeN5nLhx1poE7JzySlOWAHZL6K6Ksvg2Bli4E4Pi+8fwjnUV5rpTk3Yph3B2Ys btjvIlrE/eWLbW2qtrJDZdAbaMnzUVo= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-184-pzvsJf6aPruLJH2f2paQ0g-1; Mon, 25 Mar 2024 10:57:33 -0400 X-MC-Unique: pzvsJf6aPruLJH2f2paQ0g-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id C6BF53811F22; Mon, 25 Mar 2024 14:57:32 +0000 (UTC) Received: from MiWiFi-R3L-srv.redhat.com (unknown [10.72.116.12]) by smtp.corp.redhat.com (Postfix) with ESMTP id C39653C20; Mon, 25 Mar 2024 14:57:29 +0000 (UTC) From: Baoquan He To: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, x86@kernel.org, linuxppc-dev@lists.ozlabs.org, akpm@linux-foundation.org, rppt@kernel.org, Baoquan He Subject: [PATCH v2 4/6] mm/mm_init.c: remove meaningless calculation of zone->managed_pages in free_area_init_core() Date: Mon, 25 Mar 2024 22:56:44 +0800 Message-ID: <20240325145646.1044760-5-bhe@redhat.com> In-Reply-To: <20240325145646.1044760-1-bhe@redhat.com> References: <20240325145646.1044760-1-bhe@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.1 Content-Type: text/plain; charset="utf-8" Currently, in free_area_init_core(), when initialize zone's field, a rough value is set to zone->managed_pages. That value is calculated by (zone->present_pages - memmap_pages). In the meantime, add the value to nr_all_pages and nr_kernel_pages which represent all free pages of system (only low memory or including HIGHMEM memory separately). Both of them are gonna be used in alloc_large_system_hash(). However, the rough calculation and setting of zone->managed_pages is meaningless because a) memmap pages are allocated on units of node in sparse_init() or alloc_node_mem_map(pgdat); The simple (zone->present_pages - memmap_pages) is too rough to make sense for zone; b) the set zone->managed_pages will be zeroed out and reset with acutal value in mem_init() via memblock_free_all(). Before the resetting, no buddy allocation request is issued. Here, remove the meaningless and complicated calculation of (zone->present_pages - memmap_pages), initialize zone->managed_pages as 0 which reflect its actual value because no any page is added into buddy system right now. It will be reset in mem_init(). And also remove the assignment of nr_all_pages and nr_kernel_pages in free_area_init_core(). Instead, call the newly added calc_nr_kernel_pages() to count up all free but not reserved memory in memblock and assign to nr_all_pages and nr_kernel_pages. The counting excludes memmap_pages, and other kernel used data, which is more accurate than old way and simpler, and can also cover the ppc required arch_reserved_kernel_pages() case. And also clean up the outdated code comment above free_area_init_core(). And free_area_init_core() is easy to understand now, no need to add words to explain. Signed-off-by: Baoquan He Reviewed-by: Mike Rapoport (IBM) --- mm/mm_init.c | 46 +++++----------------------------------------- 1 file changed, 5 insertions(+), 41 deletions(-) diff --git a/mm/mm_init.c b/mm/mm_init.c index c57a7fc97a16..7f71e56e83f3 100644 --- a/mm/mm_init.c +++ b/mm/mm_init.c @@ -1565,15 +1565,6 @@ void __ref free_area_init_core_hotplug(struct pglist= _data *pgdat) } #endif =20 -/* - * Set up the zone data structures: - * - mark all pages reserved - * - mark all memory queues empty - * - clear the memory bitmaps - * - * NOTE: pgdat should get zeroed by caller. - * NOTE: this function is only called during early init. - */ static void __init free_area_init_core(struct pglist_data *pgdat) { enum zone_type j; @@ -1584,41 +1575,13 @@ static void __init free_area_init_core(struct pglis= t_data *pgdat) =20 for (j =3D 0; j < MAX_NR_ZONES; j++) { struct zone *zone =3D pgdat->node_zones + j; - unsigned long size, freesize, memmap_pages; - - size =3D zone->spanned_pages; - freesize =3D zone->present_pages; - - /* - * Adjust freesize so that it accounts for how much memory - * is used by this zone for memmap. This affects the watermark - * and per-cpu initialisations - */ - memmap_pages =3D calc_memmap_size(size, freesize); - if (!is_highmem_idx(j)) { - if (freesize >=3D memmap_pages) { - freesize -=3D memmap_pages; - if (memmap_pages) - pr_debug(" %s zone: %lu pages used for memmap\n", - zone_names[j], memmap_pages); - } else - pr_warn(" %s zone: %lu memmap pages exceeds freesize %lu\n", - zone_names[j], memmap_pages, freesize); - } - - if (!is_highmem_idx(j)) - nr_kernel_pages +=3D freesize; - /* Charge for highmem memmap if there are enough kernel pages */ - else if (nr_kernel_pages > memmap_pages * 2) - nr_kernel_pages -=3D memmap_pages; - nr_all_pages +=3D freesize; + unsigned long size =3D zone->spanned_pages; =20 /* - * Set an approximate value for lowmem here, it will be adjusted - * when the bootmem allocator frees pages into the buddy system. - * And all highmem pages will be managed by the buddy system. + * Initialize zone->managed_pages as 0 , it will be reset + * when memblock allocator frees pages into buddy system. */ - zone_init_internals(zone, j, nid, freesize); + zone_init_internals(zone, j, nid, 0); =20 if (!size) continue; @@ -1915,6 +1878,7 @@ void __init free_area_init(unsigned long *max_zone_pf= n) check_for_memory(pgdat); } =20 + calc_nr_kernel_pages(); memmap_init(); =20 /* disable hash distribution for systems with a single node */ --=20 2.41.0