K 10
svn:author
V 3
alc
K 8
svn:date
V 27
2003-11-17T18:22:24.000000Z
K 7
svn:log
V 778
 - Change the i386's sf_buf implementation so that it never allocates
   more than one sf_buf for one vm_page.  To accomplish this, we add
   a global hash table mapping vm_pages to sf_bufs and a reference
   count to each sf_buf.  (This is similar to the patches for RELENG_4
   at http://www.cs.princeton.edu/~yruan/debox/.)

   For the uninitiated, an sf_buf is nothing more than a kernel virtual
   address that is used for temporary virtual-to-physical mappings by
   sendfile(2) and zero-copy sockets.  As such, there is no reason for
   one vm_page to have several sf_bufs mapping it.  In fact, using more
   than one sf_buf for a single vm_page increases the likelihood that
   sendfile(2) blocks, hurting throughput.
   (See http://www.cs.princeton.edu/~yruan/debox/.)

END