From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Prasad Joshi" Subject: Re: need for 3G/1G split Date: Thu, 22 Mar 2007 11:11:38 +0530 Message-ID: References: <7783925d0703202115j11dbf254nc916252e4cd98e8a@mail.gmail.com> <1174473501.9500.12.camel@localhost> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: DKIM-Signature: a=rsa-sha1; c=relaxed/relaxed; d=gmail.com; s=beta; h=domainkey-signature:received:received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=ef20OwqdXoAWlpYU5E4yl0lghyaB6bruQQcQNHoRtCp1//zOY+npoixHvrf2A9ci8u1mofSEytD6j8lI/DMeDH4b1XNwZ8TXHWUJMFW7bquJPE9o10boMF0Mq5LO95gMN2Usq4AtFamzORiGsRCoTBS9GBZApchvxVUdfEy+Hr8= In-Reply-To: <1174473501.9500.12.camel@localhost> Content-Disposition: inline Sender: linux-newbie-owner@vger.kernel.org List-Id: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: vivekutal@gmail.com Cc: Rick Brown , kernelnewbies , linux-newbie@vger.kernel.org 3/21/07, Vivek wrote: > > Why is kernel restricted to use virtual addresses of only 1 GB? Or > > what is the need to split up the virtual address space into user > > addresses and kernel addresses? > > We can have 4GB for kernel and 4GB for userspace but this has a overhead > of flushing of tlb for every syscall. > You can also make the split 2/2GB but this has a problem of having less > user address space. > 3/1 is a better choice. Does TLB size change 4, 3, or 2 GB virtual addresses are used? I though it would be same irrespective of whether virtual addresses are 4 or 1 GB. If the TLB size is at all same for any number of virtual addresses then what difference it make while flushing the TLB? > > -- > Vivek Kutal > > > > -- > To unsubscribe from this list: send an email with > "unsubscribe kernelnewbies" to ecartis@nl.linux.org > Please read the FAQ at http://kernelnewbies.org/FAQ > > - To unsubscribe from this list: send the line "unsubscribe linux-newbie" 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.linux-learn.org/faqs