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From: Christoph Hellwig <hch@infradead.org>
To: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@infradead.org>,
	"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>
Subject: Re: [PATCH] block: fix -EAGAIN IOPOLL task/vm accounting
Date: Mon, 31 Aug 2020 15:12:37 +0100	[thread overview]
Message-ID: <20200831141237.GA13231@infradead.org> (raw)
In-Reply-To: <ebdb0929-782c-fb66-e3e9-86c077e3b710@kernel.dk>

On Mon, Aug 31, 2020 at 08:02:43AM -0600, Jens Axboe wrote:
> >> The use case is async submissions, going through ->read_iter() again.
> >> Or ->write_iter().
> > 
> > But how does a bio flag help there?  If we go through the file ops
> > again the next submission will be a new bio structure.
> 
> Yeah the patch is garbage, can't work. The previous suggestion is here:
> 
> https://lore.kernel.org/linux-block/395b4c19-cc80-eebb-f6ab-04687110c84a@kernel.dk/T/
> 
> which isn't super pretty either, but at least it works. Not sure there's
> a better solution, outside of marking the iocb as retry and then
> carrying that flag forward for the bio as well. And that seems a bit
> much for this case.

We'll still need a flag with the above to skip the submit_bio_noacct
bios.  But I think it is the right way to go.  Eventually we'll also
need to push the accounting down into the individual bio based drivers.

  reply	other threads:[~2020-08-31 14:12 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-29 16:51 [PATCH] block: fix -EAGAIN IOPOLL task/vm accounting Jens Axboe
2020-08-30  6:26 ` Christoph Hellwig
2020-08-30 15:09   ` Jens Axboe
2020-08-30 15:28     ` Christoph Hellwig
2020-08-31  3:12       ` Ming Lei
2020-08-31 14:02       ` Jens Axboe
2020-08-31 14:12         ` Christoph Hellwig [this message]
2020-08-31 14:18           ` Jens Axboe
2020-09-01  5:42             ` Christoph Hellwig
2020-09-01 14:01               ` Jens Axboe

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