From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qt0-f200.google.com (mail-qt0-f200.google.com [209.85.216.200]) by kanga.kvack.org (Postfix) with ESMTP id EBBA66B0033 for ; Tue, 3 Oct 2017 17:05:44 -0400 (EDT) Received: by mail-qt0-f200.google.com with SMTP id a11so1335044qti.20 for ; Tue, 03 Oct 2017 14:05:44 -0700 (PDT) Received: from mail-sor-f41.google.com (mail-sor-f41.google.com. [209.85.220.41]) by mx.google.com with SMTPS id b200sor6004176itc.42.2017.10.03.14.05.44 for (Google Transport Security); Tue, 03 Oct 2017 14:05:44 -0700 (PDT) Date: Tue, 3 Oct 2017 14:05:40 -0700 From: Tejun Heo Subject: Re: [PATCH] mm/percpu.c: use smarter memory allocation for struct pcpu_alloc_info Message-ID: <20171003210540.GM3301751@devbig577.frc2.facebook.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: Nicolas Pitre Cc: Christoph Lameter , linux-mm@kvack.org, linux-kernel@vger.kernel.org On Tue, Oct 03, 2017 at 04:57:44PM -0400, Nicolas Pitre wrote: > This can be much smaller than a page on very small memory systems. > Always rounding up the size to a page is wasteful in that case, and > required alignment is smaller than the memblock default. Let's round > things up to a page size only when the actual size is >= page size, and > then it makes sense to page-align for a nicer allocation pattern. Isn't that a temporary area which gets freed later during boot? Thanks. -- tejun -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751673AbdJCVFp (ORCPT ); Tue, 3 Oct 2017 17:05:45 -0400 Received: from mail-it0-f50.google.com ([209.85.214.50]:54828 "EHLO mail-it0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751214AbdJCVFo (ORCPT ); Tue, 3 Oct 2017 17:05:44 -0400 X-Google-Smtp-Source: AOwi7QB0UOn8ZDRXQkhfteOaQ1cQQm1XHEgDgQxQxMbQrKBUQjBf/HkFJ/gPQz9pSAg52bVcqfoxbQ== Date: Tue, 3 Oct 2017 14:05:40 -0700 From: Tejun Heo To: Nicolas Pitre Cc: Christoph Lameter , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm/percpu.c: use smarter memory allocation for struct pcpu_alloc_info Message-ID: <20171003210540.GM3301751@devbig577.frc2.facebook.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Oct 03, 2017 at 04:57:44PM -0400, Nicolas Pitre wrote: > This can be much smaller than a page on very small memory systems. > Always rounding up the size to a page is wasteful in that case, and > required alignment is smaller than the memblock default. Let's round > things up to a page size only when the actual size is >= page size, and > then it makes sense to page-align for a nicer allocation pattern. Isn't that a temporary area which gets freed later during boot? Thanks. -- tejun