Re: Patch nag: Bug #363400

[Hans Petter Jansson <hpj novell com>]

On Mon, 2007-03-26 at 10:50 +0200, Alexander Larsson wrote:
> On Wed, 2007-03-21 at 14:28 -0600, Hans Petter Jansson wrote:

> > http://bugzilla.gnome.org/show_bug.cgi?id=363400
> > 
> > Has a gnome-vfs patch that I believe to be correct. It works around a
> > serious performance issue on XFS file systems. It has been tested by at
> > least two users.

> That patch removes the size limit for when using fadvice. I don't think
> this is right. For small files we don't want to flush them from the
> cache, as that could cause performance issues (we might be copying a
> commonly used file).

No. The following condition:

if (bytes_to_write == 0 &&
    total_bytes_read - last_cache_drop_point >= DROP_CACHE_BATCH_SIZE)

Will trigger for the first time once DROP_CACHE_BATCH_SIZE has been
reached. fadvise() will be triggered at the end of each batch, not at
the beginning.

-- 
Hans Petter