From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail202.messagelabs.com (mail202.messagelabs.com [216.82.254.227]) by kanga.kvack.org (Postfix) with ESMTP id 8A4386B004F for ; Sat, 29 Aug 2009 14:17:45 -0400 (EDT) Message-ID: <4A997088.60908@zytor.com> Date: Sat, 29 Aug 2009 11:16:40 -0700 From: "H. Peter Anvin" MIME-Version: 1.0 Subject: Re: [PATCH] x86: reuse the boot-time mappings of fixed_addresses References: <4A90AADE.20307@gmail.com> <20090829110046.GA6812@elte.hu> In-Reply-To: <20090829110046.GA6812@elte.hu> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Ingo Molnar Cc: Xiao Guangrong , Andrew Morton , Rusty Russell , Jens Axboe , Xiao Guangrong , LKML , linux-mm@kvack.org, x86@kernel.org, Jeremy Fitzhardinge , Thomas Gleixner List-ID: Ingo Molnar wrote: > * Xiao Guangrong wrote: > >> From: Xiao Guangrong >> >> Some fixed_addresses items are only used when system boot, after >> boot, they are free but no way to use, like early ioremap area. >> They are wasted for us, we can reuse them after system boot. >> >> In this patch, we put them in permanent kmap's area and expand >> vmalloc's address range. In boot time, reserve them in >> permanent_kmaps_init() to avoid multiple used, after system boot, >> we unreserved them then user can use it. >> >> Signed-off-by: Xiao Guangrong >> --- >> arch/x86/include/asm/fixmap.h | 2 ++ >> arch/x86/include/asm/pgtable_32_types.h | 4 ++-- >> arch/x86/mm/init_32.c | 8 ++++++++ >> include/linux/highmem.h | 2 ++ >> mm/highmem.c | 26 ++++++++++++++++++++++++++ >> 5 files changed, 40 insertions(+), 2 deletions(-) > > I'm wondering, how much space do we save this way, on a typical > bootup on a typical PC? > Not a huge lot... a few dozen pages. -hpa -- 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