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Date: Tue, 31 Oct 2000 01:11:29 -0500
From: Brian Gerst <bgerst@didntduck.org>
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To: "H. Peter Anvin" <hpa@zytor.com>
CC: linux-kernel@vger.kernel.org
Subject: Re: kmalloc() allocation.
In-Reply-To: <E13qJZL-00076K-00@the-village.bc.nu> <Pine.LNX.3.95.1001030133720.3346A-100000@chaos.analogic.com> <8tll94$hc9$1@cesium.transmeta.com>
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"H. Peter Anvin" wrote:
> 
> Followup to:  <Pine.LNX.3.95.1001030133720.3346A-100000@chaos.analogic.com>
> By author:    "Richard B. Johnson" <root@chaos.analogic.com>
> In newsgroup: linux.dev.kernel
> >
> > > 64K probably less. kmalloc allocates physically linear spaces. vmalloc will
> > > happily grab you 2Mb of space but it will not be physically linear
> > >
> >
> > Okay. Thanks.
> >
> 
> FWIW, vmalloc()-allocated pages are definitely pinned-down and
> available to interrupts.  However, you should keep in mind that the
> vmalloc() call *itself* is quite expensive on SMP machines (have to
> interrupt all CPUs and flush their TLBs!!) so if you're using
> vmalloc(), be careful with the number of calls you make.  Of course,
> this is usually not a problem.

This was just changed in 2.4 so that vmalloced pages are faulted in on
demand.

--

					Brian Gerst
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