Date: Thu, 30 Apr 2009 21:20:09 +0000 (UTC) From: Hiroki Sato <hrs@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-releng@freebsd.org Subject: svn commit: r191705 - releng/7.2/release/doc/en_US.ISO8859-1/relnotes Message-ID: <200904302120.n3ULK9m2023130@svn.freebsd.org>
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Author: hrs Date: Thu Apr 30 21:20:09 2009 New Revision: 191705 URL: http://svn.freebsd.org/changeset/base/191705 Log: Revise entry for superpages. Suggested by: rwatson Approved by: re (implicit) Modified: releng/7.2/release/doc/en_US.ISO8859-1/relnotes/article.sgml Modified: releng/7.2/release/doc/en_US.ISO8859-1/relnotes/article.sgml ============================================================================== --- releng/7.2/release/doc/en_US.ISO8859-1/relnotes/article.sgml Thu Apr 30 19:25:44 2009 (r191704) +++ releng/7.2/release/doc/en_US.ISO8859-1/relnotes/article.sgml Thu Apr 30 21:20:09 2009 (r191705) @@ -296,15 +296,16 @@ <literal>VFS_AIO</literal>.</para> <para arch="amd64,i386">The &os; virtual memory subsystem now - supports <application>Superpages</application>. The - <application>Superpages</application> is a feature that - enables each entry in the TLB (translation lookaside buffer) - to map a large physical memory region into a virtual address - space in modern CPUs. This provides possible memory savings - for applications that share large amounts of memory between - the address spaces and performance improvements due to fewer - TLB misses. This is disabled by default and can be enabled by - setting a loader tunable + supports fully transparent use of + <application>superpages</application> for application memory; + application memory pages are dynamically promoted to or + demoted from superpages without any modification to + application code. This change offers the benefit of large + page sizes such as improved virtual memory efficiency and + reduced TLB (translation lookaside buffer) misses without + downsides like application changes and virtual memory + inflexibility. This is disabled by default and can be enabled + by setting a loader tunable <varname>vm.pmap.pg_ps_enabled</varname> to <literal>1</literal>.</para>
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