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From: Eric Wong <normalperson@yhbt.net>
To: Simon Jeons <simon.jeons@gmail.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Alan Cox <alan@lxorguk.ukuu.org.uk>,
	Dave Chinner <david@fromorbit.com>,
	Zheng Liu <gnehzuil.liu@gmail.com>
Subject: Re: [PATCH v2] fadvise: perform WILLNEED readahead asynchronously
Date: Thu, 10 Jan 2013 04:05:46 +0000	[thread overview]
Message-ID: <20130110040546.GA23797@dcvr.yhbt.net> (raw)
In-Reply-To: <1357386394.9001.0.camel@kernel.cn.ibm.com>

Simon Jeons <simon.jeons@gmail.com> wrote:
> On Tue, 2012-12-25 at 02:22 +0000, Eric Wong wrote:
> 
> Please add changelog.

Changes since v1:

* separate unbound workqueue for high-priority tasks

* account for inflight readahead to avoid denial-of-service

* limit concurrency for non-high-priority tasks (1 per CPU, same as aio)

* take IO priority of requesting process into account when in workqueue.

* process queued readahead in 2M chunks to help ensure fairness between
  multiple requests with few CPUs/workqueues.  Idle tasks get smaller
  256K chunks.

* stops readahead for idle tasks on read congestion

Will try to benchmark with Postgres when I get the chance.

Any other (Free Software) applications that might benefit from
lower FADV_WILLNEED latency?

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WARNING: multiple messages have this Message-ID (diff)
From: Eric Wong <normalperson@yhbt.net>
To: Simon Jeons <simon.jeons@gmail.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Alan Cox <alan@lxorguk.ukuu.org.uk>,
	Dave Chinner <david@fromorbit.com>,
	Zheng Liu <gnehzuil.liu@gmail.com>
Subject: Re: [PATCH v2] fadvise: perform WILLNEED readahead asynchronously
Date: Thu, 10 Jan 2013 04:05:46 +0000	[thread overview]
Message-ID: <20130110040546.GA23797@dcvr.yhbt.net> (raw)
In-Reply-To: <1357386394.9001.0.camel@kernel.cn.ibm.com>

Simon Jeons <simon.jeons@gmail.com> wrote:
> On Tue, 2012-12-25 at 02:22 +0000, Eric Wong wrote:
> 
> Please add changelog.

Changes since v1:

* separate unbound workqueue for high-priority tasks

* account for inflight readahead to avoid denial-of-service

* limit concurrency for non-high-priority tasks (1 per CPU, same as aio)

* take IO priority of requesting process into account when in workqueue.

* process queued readahead in 2M chunks to help ensure fairness between
  multiple requests with few CPUs/workqueues.  Idle tasks get smaller
  256K chunks.

* stops readahead for idle tasks on read congestion

Will try to benchmark with Postgres when I get the chance.

Any other (Free Software) applications that might benefit from
lower FADV_WILLNEED latency?

  reply	other threads:[~2013-01-10  4:05 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-12-25  2:22 [PATCH v2] fadvise: perform WILLNEED readahead asynchronously Eric Wong
2012-12-25  2:22 ` Eric Wong
2012-12-27  7:01 ` Zheng Liu
2012-12-27  7:01   ` Zheng Liu
2013-01-05 11:46 ` Simon Jeons
2013-01-05 11:46   ` Simon Jeons
2013-01-10  4:05   ` Eric Wong [this message]
2013-01-10  4:05     ` Eric Wong
2013-01-10  9:35 ` [v2] " Riccardo Magliocchetti
2013-01-10  9:35   ` Riccardo Magliocchetti
2013-01-10 11:14   ` Eric Wong
2013-01-10 11:14     ` Eric Wong

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