Re: [PATCH 03/15] writeback: introducewriteback_control.inodes_cleaned

From: Andrew Morton
Date: Tue Jun 07 2011 - 19:04:26 EST


On Wed, 08 Jun 2011 05:32:39 +0800
Wu Fengguang <fengguang.wu@xxxxxxxxx> wrote:

> The flusher works on dirty inodes in batches, and may quit prematurely
> if the batch of inodes happen to be metadata-only dirtied: in this case
> wbc->nr_to_write won't be decreased at all, which stands for "no pages
> written" but also mis-interpreted as "no progress".
>
> So introduce writeback_control.inodes_cleaned to count the inodes get
> cleaned. A non-zero value means there are some progress on writeback,
> in which case more writeback can be tried.

Yes, that makes sense. I had a workload which demonstrated/exploited
this nine years ago but I never got around to fixing it, never told
anyone and nobody noticed ;)

> + long inodes_cleaned; /* # of inodes cleaned */

nanonit: I'd call this inodes_written, because they may not actually be
clean.
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