Date: Sun, 18 Apr 1999 12:58:01 -0700 (PDT) From: Matthew Dillon <dillon@apollo.backplane.com> To: Peter Wemm <peter@netplex.com.au> Cc: "John S. Dyson" <toor@dyson.iquest.net>, dyson@iquest.net, dg@root.com, hackers@freebsd.org Subject: Re: Directories not VMIO cached at all! Message-ID: <199904181958.MAA81828@apollo.backplane.com> References: <19990418164232.4DC7C1F2A@spinner.netplex.com.au>
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:> the amount of memory used for caching directories. The disadvantage
:> is the potentially gross amount of internal fragmentation of memory.
:>
:> Perhaps before getting rid of B_MALLOC, take a look at the standard
:> mix of directory sizes (don't just look at news servers.) If there is an
:> extreme bias towards 512 or 2048, then you might consider keeping B_MALLOC.
:
:Would small block devices/filesystems likely be affected? (ie: msdos,
:ext2fs etc)
:
:Cheers,
:-Peter
Remember all those VFS/BIO fixes Luoqi made a few weeks ago? They
were mainly to fix bugs in VFS/BIO relating to small block filesystems.
small block filesystems use VMIO, but since the block size is less then
a page the base offset in the struct buf for any given small-block buffer
is *NOT* the same as the base offset the page being mapped to that
struct buf.
We could conceivably do the same thing with directories, but it probably
would not be worth the hassle.
-Matt
Matthew Dillon
<dillon@backplane.com>
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