LKML Archive on
help / color / mirror / Atom feed
From: Jeff Garzik <>
To: Ed Lin <>
Cc: Jens Axboe <>,
	David Somayajulu <>,
	Michael Reed <>,
	linux-scsi <>,
	linux-kernel <>,
	"james.Bottomley" <>,
	Promise_Linux <>
Subject: Re: [patch] scsi: use lock per host instead of per device for shared queue tag host
Date: Thu, 25 Jan 2007 20:21:01 -0500	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

Ed Lin wrote:
> There may possibly be some other errors. So we need a lock here.
> I think the simple but reliable way to do it is just to replace
> queue lock with a host lock. James pointed out that there may be
> performance slow down when many devices are accessed at the
> same time. But I think the major part is still on the hardware,
> and a host lock is the price these kind of controllers must pay.

I agree.

Further, a host lock is (a) common across many controllers, to protect 
host-wide resources and (b) only limits us when the controller is 
CPU-limited, a very rare scenario.


  reply	other threads:[~2007-01-26  1:21 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-01-26  1:15 Ed Lin
2007-01-26  1:21 ` Jeff Garzik [this message]
  -- strict thread matches above, loose matches on Subject: below --
2007-01-25  3:14 Ed Lin
2007-01-25 15:34 ` Jens Axboe
2007-01-25 15:47   ` Jens Axboe
2007-01-24 23:33 Ed Lin
2007-01-25  1:02 ` David Somayajulu
2007-01-24  0:53 Ed Lin
2007-01-24 15:59 ` Michael Reed
2007-01-24 16:59 ` James Bottomley

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \ \ \ \ \ \ \ \ \ \ \
    --subject='Re: [patch] scsi: use lock per host instead of per device for shared queue tag host' \

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).