Re: kmalloc() allocation.

From: Brian Gerst (bgerst@didntduck.org)
Date: Tue Oct 31 2000 - 01:11:29 EST


"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.

--

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