From: Jan Kara <jack@suse.cz>
Subject: Re: [PATCH 1/6] writeback: fix writeback completion notifications
Date: Tue, 15 Jun 2010 19:25:15 +0200
Message-ID: <20100615172515.GF3347@quack.suse.cz>
References: <20100608161424.GA11735@lst.de>
 <20100608161434.GB11735@lst.de>
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Cc: axboe@kernel.dk, linux-fsdevel@vger.kernel.org
To: Christoph Hellwig <hch@lst.de>
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In-Reply-To: <20100608161434.GB11735@lst.de>
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On Tue 08-06-10 18:14:34, Christoph Hellwig wrote:
> The code dealing with bdi_work->state and completion of a bdi_work is a
> major mess currently.  This patch makes sure we directly use one set of
> flags to deal with it, and use it consistently, which means:
> 
>  - always notify about completion from the rcu callback.  We only ever
>    wait for it from on-stack callers, so this simplification does not
>    even cause a theoretical slowdown currently.  It also makes sure we
>    don't miss out on the notification if we ever add other callers to
>    wait for it.
>  - make earlier completion notification depending on the on-stack
>    allocation, not the sync mode.  If we introduce new callers that
>    want to do WB_SYNC_NONE writeback from on-stack callers this will
>    be nessecary.
> 
> Also rename bdi_wait_on_work_clear to bdi_wait_on_work_done and inline
  What I find slightly misleading on bdi_wait_on_work_done is that work
isn't always "done" when this returns. For WB_SYNC_NONE writeback this
function returns as soon as writeback thread starts the work... But I don't
have a better name.

								Honza

-- 
Jan Kara <jack@suse.cz>
SUSE Labs, CR