Re: [PATCH] ide write barrier support

From: Jens Axboe
Date: Thu Oct 16 2003 - 02:12:10 EST


On Tue, Oct 14 2003, Greg Stark wrote:
>
> Jens Axboe <axboe@xxxxxxx> writes:
>
> > Hi,
> >
> > Forward ported and tested today (with the dummy ext3 patch included),
> > works for me. Some todo's left, but I thought I'd send it out to gauge
> > interest. TODO:
>
>
> Is there a user-space interface planned for this?

I don't have one planned.

> One possibility may be just to hang it off fsync(2) so fsync doesn't
> return until until all the buffers it flushed are actually synced to
> disk. That's its documented semantics anyways.

Makes sense, indeed.

> There's also the case of files opened with O_SYNC. Would inserting a
> write barrier after every write to such a file destroy performance?

If it's mainly sequential io, then no it won't destroy performance. It
will be lower than without the cache flush of course.

--
Jens Axboe

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