Re: stochastic fair queueing in the elevator [Re: [BENCHMARK]

Rik van Riel (riel@conectiva.com.br)
Mon, 10 Feb 2003 02:47:19 -0200 (BRST)

On Sun, 9 Feb 2003, Andrew Morton wrote:
> David Lang <david.lang@digitalinsight.com> wrote:
> >
> > note that issuing a fsync should change all pending writes to 'syncronous'
> > as should writes to any partition mounted with the sync option, or writes
> > to a directory with the S flag set.
>
> We know, at I/O submission time, whether a write is to be waited upon.
> That's in writeback_control.sync_mode.

An fsync might change already submitted asynchronous writes
into synchronous writes, but this is not something I'm going
to lose sleep over. ;)

> That, combined with an assumption that "all reads are synchronous" would
> allow the outgoing BIOs to be appropriately tagged.
>
> It's still approximate.

Sounds like a good enough approximation to me.

Rik

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