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Date: Thu, 8 Dec 2016 16:01:11 +0300
From: Slawa Olhovchenkov <slw@zxy.spb.ru>
To: Alan Cox <alc@FreeBSD.org>
Cc: src-committers@freebsd.org, svn-src-all@freebsd.org,
 svn-src-head@freebsd.org
Subject: Re: svn commit: r309703 - in head/sys: amd64/amd64 arm64/arm64
 i386/i386 vm
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On Thu, Dec 08, 2016 at 04:29:29AM +0000, Alan Cox wrote:

> Author: alc
> Date: Thu Dec  8 04:29:29 2016
> New Revision: 309703
> URL: https://svnweb.freebsd.org/changeset/base/309703
> 
> Log:
>   Previously, vm_radix_remove() would panic if the radix trie didn't
>   contain a vm_page_t at the specified index.  However, with this
>   change, vm_radix_remove() no longer panics.  Instead, it returns NULL
>   if there is no vm_page_t at the specified index.  Otherwise, it
>   returns the vm_page_t.  The motivation for this change is that it
>   simplifies the use of radix tries in the amd64, arm64, and i386 pmap
>   implementations.  Instead of performing a lookup before every remove,
>   the pmap can simply perform the remove.

Is this performance improvement?