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 X-Spam-Level: X-Spam-Status: No, score=-7.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B60DCC433DF for ; Wed, 24 Jun 2020 16:52:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 904FE2073E for ; Wed, 24 Jun 2020 16:52:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="C3Aq1EOx" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2405274AbgFXQw2 (ORCPT ); Wed, 24 Jun 2020 12:52:28 -0400 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:35974 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2404017AbgFXQw1 (ORCPT ); Wed, 24 Jun 2020 12:52:27 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1593017546; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=YgOG3Qn9UrbkC82Csvd2S1YBbX7wsXZhXBrd7kB7GaE=; b=C3Aq1EOxuQXfzCxHMRimNJ+GXjogDz2LvE7uonKeZwnQqWLNMMHAX240bo06L360qLJeia Jwk+i62GJ9eAnMeMb6grGCoAwCgKEGzplRcDWuIMUUH4W6CSnuSZFLUcOcva+7RkFK/1BO NtL/Pd57oecoq0dB17BNYgTunDsYClw= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-299-9XDBz30yN5y-jP_osSf3Ow-1; Wed, 24 Jun 2020 12:52:24 -0400 X-MC-Unique: 9XDBz30yN5y-jP_osSf3Ow-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id AE81A107ACF4; Wed, 24 Jun 2020 16:52:22 +0000 (UTC) Received: from jsavitz.bos.com (ovpn-112-219.rdu2.redhat.com [10.10.112.219]) by smtp.corp.redhat.com (Postfix) with ESMTP id C8C552B4AB; Wed, 24 Jun 2020 16:52:18 +0000 (UTC) From: Joel Savitz To: linux-kernel@vger.kernel.org Cc: Joel Savitz , Vlastimil Babka , John Hubbard , Andrew Morton , Rafael Aquini , Fabrizio D'Angelo , linux-mm@kvack.org Subject: [PATCH v2] mm/page_alloc: fix documentation error and remove magic numbers Date: Wed, 24 Jun 2020 12:49:43 -0400 Message-Id: <20200624164943.32048-1-jsavitz@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When I increased the upper bound of the min_free_kbytes value in ee8eb9a5fe863, I forgot to tweak the above comment to reflect the new value. This patch fixes that mistake. In addition, this patch replaces the magic number bounds with symbolic constants to clarify the logic. changes from v1: - declare constants via enum instead of separate integers Suggested-by: John Hubbard Suggested-by: Vlastimil Babka Signed-off-by: Joel Savitz --- mm/page_alloc.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 48eb0f1410d4..733c81678b0e 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -7832,7 +7832,7 @@ void setup_per_zone_wmarks(void) * Initialise min_free_kbytes. * * For small machines we want it small (128k min). For large machines - * we want it large (64MB max). But it is not linear, because network + * we want it large (256MB max). But it is not linear, because network * bandwidth does not increase linearly with machine size. We use * * min_free_kbytes = 4 * sqrt(lowmem_kbytes), for better accuracy: @@ -7852,6 +7852,8 @@ void setup_per_zone_wmarks(void) * 8192MB: 11584k * 16384MB: 16384k */ +static enum { MIN_FREE_KBYTES_LOWER_BOUND = 1 << 7, MIN_FREE_KBYTES_UPPER_BOUND = 1 << 18 }; + int __meminit init_per_zone_wmark_min(void) { unsigned long lowmem_kbytes; @@ -7862,10 +7864,10 @@ int __meminit init_per_zone_wmark_min(void) if (new_min_free_kbytes > user_min_free_kbytes) { min_free_kbytes = new_min_free_kbytes; - if (min_free_kbytes < 128) - min_free_kbytes = 128; - if (min_free_kbytes > 262144) - min_free_kbytes = 262144; + if (min_free_kbytes < MIN_FREE_KBYTES_LOWER_BOUND) + min_free_kbytes = MIN_FREE_KBYTES_LOWER_BOUND; + if (min_free_kbytes > MIN_FREE_KBYTES_UPPER_BOUND) + min_free_kbytes = MIN_FREE_KBYTES_UPPER_BOUND; } else { pr_warn("min_free_kbytes is not updated to %d because user defined value %d is preferred\n", new_min_free_kbytes, user_min_free_kbytes); -- 2.23.0