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 DA29CC433E0 for ; Wed, 24 Jun 2020 03:27:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 92FC620767 for ; Wed, 24 Jun 2020 03:27:57 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="ipacoM1s" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388816AbgFXD14 (ORCPT ); Tue, 23 Jun 2020 23:27:56 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:20778 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2387985AbgFXD1y (ORCPT ); Tue, 23 Jun 2020 23:27:54 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1592969272; 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=LuTtoSGXJewNeG9sj4V/BG+fVb0iM20PQFKrLVPrSAI=; b=ipacoM1stEqjc/0SmMzYTQuYGyIdl9P7ArLtSeSRPKijV4ALW/LXqZJuxEKxuQbqgGN6Cn 4yolIuc6tqnTJUD4bg9uCtkLSYPlJaouIuaLzwYzxZxTbDz172TQCh77dKwFgOuMOCJrWI cKd4Z/LZy+IFH7dbbSyF4gxCcnfCAjc= 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-369-P7bqO8BOPtCyaMwSwRWzoQ-1; Tue, 23 Jun 2020 23:27:51 -0400 X-MC-Unique: P7bqO8BOPtCyaMwSwRWzoQ-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 9DB65464; Wed, 24 Jun 2020 03:27:49 +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 F115A60C1D; Wed, 24 Jun 2020 03:27:45 +0000 (UTC) From: Joel Savitz To: linux-kernel@vger.kernel.org Cc: Joel Savitz , Vlastimil Babka , John Hubbard , Andrew Morton , Rafael Aquini , linux-mm@kvack.org Subject: [PATCH] mm/page_alloc: fix documentation error and remove magic numbers Date: Tue, 23 Jun 2020 23:27:12 -0400 Message-Id: <20200624032712.23263-1-jsavitz@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 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. Suggested-by: John Hubbard Suggested-by: Vlastimil Babka Signed-off-by: Joel Savitz --- mm/page_alloc.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 48eb0f1410d4..f725addc2748 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 +7852,9 @@ void setup_per_zone_wmarks(void) * 8192MB: 11584k * 16384MB: 16384k */ +static const int MIN_FREE_KBYTES_LOWER_BOUND = 1 << 7; +static const int MIN_FREE_KBYTES_UPPER_BOUND = 1 << 18; + int __meminit init_per_zone_wmark_min(void) { unsigned long lowmem_kbytes; @@ -7862,10 +7865,10 @@ 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