vfs.ffs.rawreadahead

[Sujit Karataparambil]

These are Journalling File System. Some thing like WAPBL
which stands for Write-Ahead Physical Block Logging. These
are built on Generic kernel components.

On 9/3/08, Igor Sysoev <is at rambler-co.ru> wrote:
> On Wed, Sep 03, 2008 at 04:03:59PM +0530, Sujit Karataparambil wrote:
>
> > The VFS was designed to be Object abtraction of the Berkeley Fast File System.
> > This has been since an terminology with journalling filesystem to have
> > functionality to added on request.
>
> In src/sys/ufs/ffs/ffs_rawread.c I see that rawreadahead is used.
> However, I do not understand whether rawreadahead starts a second
> parallel ahead disk transaction with supplied userland buffer or not.
>
>
> --
> Igor Sysoev
> http://sysoev.ru/en/
>
> > On 9/3/08, Igor Sysoev <is at rambler-co.ru> wrote:
> > > Hi,
> > >
> > > could anyone tell what does vfs.ffs.rawreadahead enable ?
> > > As I understand it's used in DIRECTIO code that allows read data
> > > directly to an userland buffer bypassing the buffer cache.
> > > What I can not understand where the read ahead data can be placed in ?
> > >
> > >
> > > --
> > > Igor Sysoev
> > > http://sysoev.ru/en/
>


-- 
--linux(2.4/2.6),bsd(4.5.x+),solaris(2.5+)