From: Tejun Heo <tj@kernel.org>
To: Dan Williams <dan.j.williams@intel.com>
Cc: linux-scsi@vger.kernel.org, linux-ide@vger.kernel.org
Subject: Re: [PATCH 02/24] workqueue: defer work to a draining queue
Date: Mon, 19 Dec 2011 14:08:41 -0800 [thread overview]
Message-ID: <20111219220841.GB6256@google.com> (raw)
In-Reply-To: <CAA9_cmffHn0tqjF55ZAYi_xG=JakwK28QP=Vj=irP9MwoqWBSw@mail.gmail.com>
Hello,
On Mon, Dec 19, 2011 at 02:01:47PM -0800, Dan Williams wrote:
> > Dan, as I replied before, I'm not a big fan of this approach.
>
> Sorry I must have missed it, I can't seem to find a reply in the archives?
Yeah, I can't find it either. I definitely remember writing it.
Hmmm... weird. Either I'm finally losing my mind or it didn't get out
for some reason. Sorry. :)
> > For
> > now, I think it would be best to add private wrapper in libsas to
> > support deferring unchained work items while draining.
>
> Ok, a form of this was nak'd by James before [1], but I can try again
> with pushing this chained submission checking down into scsi.
The issues I see with the proposed change is,
* There doesn't seem to be high demand for it.
* It isn't implemented the right way - it introduces unnecessary and
hidden ordering between chained work items being drained and newly
queued unchained ones. We can try to do it properly without
affecting new unchained work items but I'm not sure the added
complexity is justified given the first issue.
I don't think adding a wrapper which defers queueing while draining is
going on would be too complex, right?
Thank you.
--
tejun
next prev parent reply other threads:[~2011-12-19 22:08 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-17 2:33 [PATCH 00/24] libsas: eh reworks (ata-eh vs discovery, races, ...) Dan Williams
2011-12-17 2:33 ` [PATCH 01/24] workqueue: promote workqueue_lock to hard-irq safe Dan Williams
2011-12-17 2:33 ` [PATCH 02/24] workqueue: defer work to a draining queue Dan Williams
2011-12-19 21:49 ` Tejun Heo
2011-12-19 22:01 ` Dan Williams
2011-12-19 22:08 ` Tejun Heo [this message]
2011-12-19 22:25 ` Williams, Dan J
2011-12-17 2:33 ` [PATCH 03/24] scsi: use drain_workqueue Dan Williams
2011-12-17 2:33 ` [PATCH 04/24] libsas: remove unused ata_task_resp fields Dan Williams
2011-12-17 12:51 ` Sergei Shtylyov
2011-12-19 1:38 ` Jack Wang
2011-12-17 2:33 ` [PATCH 05/24] libsas: kill sas_slave_destroy Dan Williams
2011-12-17 2:33 ` [PATCH 06/24] libsas: fix domain_device leak Dan Williams
2011-12-19 2:32 ` Jack Wang
2011-12-17 2:33 ` [PATCH 07/24] libsas: fix leak of dev->sata_dev.identify_[packet_]device Dan Williams
2011-12-19 2:38 ` Jack Wang
2011-12-17 2:33 ` [PATCH 08/24] libsas: replace event locks with atomic bitops Dan Williams
2011-12-17 2:33 ` [PATCH 09/24] libsas: remove ata_port.lock management duties from lldds Dan Williams
2011-12-17 2:33 ` [PATCH 10/24] libsas: prevent domain rediscovery competing with ata error handling Dan Williams
2011-12-17 2:34 ` [PATCH 11/24] libsas: use ->set_dmamode to notify lldds of NCQ parameters Dan Williams
2011-12-17 2:34 ` [PATCH 12/24] libsas: kill invocation of scsi_eh_finish_cmd from sas_ata_task_done Dan Williams
2011-12-17 2:34 ` [PATCH 13/24] libsas: close error handling vs sas_ata_task_done() race Dan Williams
2011-12-17 2:34 ` [PATCH 14/24] libsas: prevent double completion of scmds from eh Dan Williams
2011-12-17 13:08 ` Sergei Shtylyov
2011-12-18 19:19 ` Dan Williams
2011-12-17 13:13 ` Sergei Shtylyov
2011-12-18 19:24 ` Dan Williams
2011-12-17 2:34 ` [PATCH 15/24] libsas: fix timeout vs completion race Dan Williams
2011-12-17 2:34 ` [PATCH 16/24] libsas: let libata handle command timeouts Dan Williams
2011-12-17 2:34 ` [PATCH 17/24] libsas: defer SAS_TASK_NEED_DEV_RESET commands to libata Dan Williams
2011-12-17 2:34 ` [PATCH 18/24] libsas: use libata-eh-reset for sata rediscovery fis transmit failures Dan Williams
2011-12-17 2:34 ` [PATCH 19/24] libsas: execute transport link resets with libata-eh via host workqueue Dan Williams
2011-12-17 2:34 ` [PATCH 20/24] libsas: sas_phy_enable via transport_sas_phy_reset Dan Williams
2011-12-17 2:34 ` [PATCH 21/24] libsas: Remove redundant phy state notification calls Dan Williams
2011-12-17 2:35 ` [PATCH 22/24] libsas: add mutex for SMP task execution Dan Williams
2011-12-17 2:35 ` [PATCH 23/24] libsas: async ata-eh Dan Williams
2011-12-17 2:35 ` [PATCH 24/24] libsas: poll for ata device readiness after reset Dan Williams
2011-12-20 6:18 ` Jack Wang
2011-12-20 7:08 ` Williams, Dan J
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