From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755971AbdCGSoO (ORCPT ); Tue, 7 Mar 2017 13:44:14 -0500 Received: from bombadil.infradead.org ([65.50.211.133]:47713 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755781AbdCGSoI (ORCPT ); Tue, 7 Mar 2017 13:44:08 -0500 Date: Tue, 7 Mar 2017 10:28:41 -0800 From: Matthew Wilcox To: Michal Hocko Cc: Andrew Morton , Al Viro , Vlastimil Babka , David Rientjes , Cristopher Lameter , linux-mm@kvack.org, LKML , Michal Hocko Subject: Re: [PATCH] mm, vmalloc: use __GFP_HIGHMEM implicitly Message-ID: <20170307182841.GS16328@bombadil.infradead.org> References: <20170307141020.29107-1-mhocko@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170307141020.29107-1-mhocko@kernel.org> User-Agent: Mutt/1.7.1 (2016-10-04) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Mar 07, 2017 at 03:10:20PM +0100, Michal Hocko wrote: > From: Michal Hocko > > __vmalloc* allows users to provide gfp flags for the underlying > allocation. This API is quite popular > $ git grep "=[[:space:]]__vmalloc\|return[[:space:]]*__vmalloc" | wc -l > 77 > > the only problem is that many people are not aware that they really want > to give __GFP_HIGHMEM along with other flags because there is really no > reason to consume precious lowmemory on CONFIG_HIGHMEM systems for pages > which are mapped to the kernel vmalloc space. About half of users don't > use this flag, though. This signals that we make the API unnecessarily > too complex. > > This patch simply uses __GFP_HIGHMEM implicitly when allocating pages to > be mapped to the vmalloc space. Current users which add __GFP_HIGHMEM > are simplified and drop the flag. > > Signed-off-by: Michal Hocko Reviewed-by: Matthew Wilcox