From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Subject: Re: [PATCH 2/4] Convert epoll to a bitlock Date: Tue, 3 Feb 2009 13:39:42 -0800 Message-ID: <20090203133942.2ecec281.akpm@linux-foundation.org> References: <1233598811-6871-1-git-send-email-corbet@lwn.net> <1233598811-6871-3-git-send-email-corbet@lwn.net> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1233598811-6871-3-git-send-email-corbet-T1hC0tSOHrs@public.gmane.org> Sender: linux-api-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, andi-Vw/NltI1exuRpAAqCnN02g@public.gmane.org, oleg-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, viro-3bDd1+5oDREiFSDQTTA3OLVCufUGDwFn@public.gmane.org, davidel-AhlLAIvw+VEjIGhXcJzhZg@public.gmane.org, davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org, hch-jcswGhMUV9g@public.gmane.org, linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, mpm-VDJrAJ4Gl5ZBDgjK7y7TUQ@public.gmane.org, alan-qBU/x9rampVanCEyBjwyrvXRex20P6io@public.gmane.org, corbet-T1hC0tSOHrs@public.gmane.org List-Id: linux-api@vger.kernel.org On Mon, 2 Feb 2009 11:20:09 -0700 Jonathan Corbet wrote: > Matt Mackall suggested converting epoll's ep_lock to a bitlock as a way of > saving space in struct file. This patch makes that change. hrm. bit_spin_lock() makes people upset (large penguiny people). iirc it doesn't have all the correct/well-understood memory/compiler ordering semantics which spinlocks have. And lockdep doesn't know about it. -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html