From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with ESMTP id 573A96B0098 for ; Mon, 31 Aug 2009 04:26:38 -0400 (EDT) Date: Mon, 31 Aug 2009 10:26:32 +0200 From: Ingo Molnar Subject: Re: [PATCH] x86: reuse the boot-time mappings of fixed_addresses Message-ID: <20090831082632.GB15619@elte.hu> References: <4A90AADE.20307@gmail.com> <20090829110046.GA6812@elte.hu> <4A997088.60908@zytor.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4A997088.60908@zytor.com> Sender: owner-linux-mm@kvack.org To: "H. Peter Anvin" 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: * H. Peter Anvin wrote: > 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. I guess it's still worth doing - what do you think? Ingo -- 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