From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756992Ab3BFCJj (ORCPT ); Tue, 5 Feb 2013 21:09:39 -0500 Received: from LGEMRELSE6Q.lge.com ([156.147.1.121]:51631 "EHLO LGEMRELSE6Q.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754836Ab3BFCJg (ORCPT ); Tue, 5 Feb 2013 21:09:36 -0500 X-AuditID: 9c930179-b7c24ae00000119c-1e-5111bb5e54aa Date: Wed, 6 Feb 2013 11:09:42 +0900 From: Joonsoo Kim To: Santosh Shilimkar Cc: Russell King , Nicolas Pitre , Catalin Marinas , Will Deacon , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v5 0/3] introduce static_vm for ARM-specific static mapped area Message-ID: <20130206020942.GD4325@lge.com> References: <1360024314-1895-1-git-send-email-iamjoonsoo.kim@lge.com> <5110CA8E.5020606@ti.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5110CA8E.5020606@ti.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-Brightmail-Tracker: AAAAAA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, Santosh. On Tue, Feb 05, 2013 at 02:32:06PM +0530, Santosh Shilimkar wrote: > On Tuesday 05 February 2013 06:01 AM, Joonsoo Kim wrote: > >In current implementation, we used ARM-specific flag, that is, > >VM_ARM_STATIC_MAPPING, for distinguishing ARM specific static mapped area. > >The purpose of static mapped area is to re-use static mapped area when > >entire physical address range of the ioremap request can be covered > >by this area. > > > >This implementation causes needless overhead for some cases. > >For example, assume that there is only one static mapped area and > >vmlist has 300 areas. Every time we call ioremap, we check 300 areas for > >deciding whether it is matched or not. Moreover, even if there is > >no static mapped area and vmlist has 300 areas, every time we call > >ioremap, we check 300 areas in now. > > > >If we construct a extra list for static mapped area, we can eliminate > >above mentioned overhead. > >With a extra list, if there is one static mapped area, > >we just check only one area and proceed next operation quickly. > > > >In fact, it is not a critical problem, because ioremap is not frequently > >used. But reducing overhead is better idea. > > > >Another reason for doing this work is for removing vm_struct list management, > >entirely. For more information, look at the following link. > >http://lkml.org/lkml/2012/12/6/184 > > > > [..] > > > > >Joonsoo Kim (3): > > ARM: vmregion: remove vmregion code entirely > > ARM: ioremap: introduce an infrastructure for static mapped area > > ARM: mm: use static_vm for managing static mapped areas > > > > arch/arm/mm/Makefile | 2 +- > > arch/arm/mm/ioremap.c | 135 +++++++++++++++++++++---------- > > arch/arm/mm/mm.h | 12 +++ > > arch/arm/mm/mmu.c | 34 ++++---- > > arch/arm/mm/vmregion.c | 205 ------------------------------------------------ > > arch/arm/mm/vmregion.h | 31 -------- > > 6 files changed, 123 insertions(+), 296 deletions(-) > > delete mode 100644 arch/arm/mm/vmregion.c > > delete mode 100644 arch/arm/mm/vmregion.h > > > Nice Clean-up. I tested this series on OMAP which uses few static > mappings. Feel free to add, > > Tested-by: Santosh Shilimkar I will re-send v6 with your Tested-by. Thanks for testing this. > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/