Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley
	Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United
	Kingdom.
	Registered in England and Wales under Company Registration No. 3798903
From: David Howells <dhowells@redhat.com>
In-Reply-To: <4B7B2F4E.5090803@kernel.org>
References: <4B7B2F4E.5090803@kernel.org> <4B7A13C6.4060402@kernel.org> <4B763C17.5080707@kernel.org> <1263776272-382-36-git-send-email-tj@kernel.org> <1263776272-382-1-git-send-email-tj@kernel.org> <24913.1265997809@redhat.com> <27102.1266246296@redhat.com> <28151.1266343557@redhat.com>
To: Tejun Heo <tj@kernel.org>
Cc: dhowells@redhat.com, torvalds@linux-foundation.org, mingo@elte.hu,
       peterz@infradead.org, awalls@radix.net, linux-kernel@vger.kernel.org,
       jeff@garzik.org, akpm@linux-foundation.org, jens.axboe@oracle.com,
       rusty@rustcorp.com.au, cl@linux-foundation.org, arjan@linux.intel.com,
       avi@redhat.com, johannes@sipsolutions.net, andi@firstfloor.org
Subject: Re: [PATCH 35/40] fscache: convert object to use workqueue instead of slow-work
Date: Thu, 18 Feb 2010 11:50:16 +0000
Message-ID: <26902.1266493816@redhat.com>
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 869
Lines: 19

Tejun Heo <tj@kernel.org> wrote:

> The waiting workers are woken up in slow_work_enqueue() when a new
> work is enqueued regardless of how many workers are currently in use,
> right?  So, it ends up yielding on any queue activity rather than only
> under resource pressure.

It depends how you define resource pressure, I suppose.  There's someone now
waiting for the resource, and there's someone blocking that resource who can
yield it as they're waiting on something else.  The question is if it's
cheaper to create a new thread, assuming we're under the limit, or if it's
cheaper to steal someone else's thread?

David
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/