From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andi Kleen Subject: Re: btrfs_tree_lock & trylock Date: Mon, 8 Sep 2008 16:20:52 +0200 Message-ID: <20080908142052.GK26079@one.firstfloor.org> References: <20080908111059.GA8902@basil.nowhere.org> <1220881666.8537.3.camel@think.oraclecorp.com> <20080908135414.GG26079@one.firstfloor.org> <1220882551.8537.5.camel@think.oraclecorp.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Andi Kleen , linux-btrfs@vger.kernel.org To: Chris Mason Return-path: In-Reply-To: <1220882551.8537.5.camel@think.oraclecorp.com> List-ID: On Mon, Sep 08, 2008 at 10:02:30AM -0400, Chris Mason wrote: > On Mon, 2008-09-08 at 15:54 +0200, Andi Kleen wrote: > > > The idea is to try to spin for a bit to avoid scheduling away, which is > > > especially important for the high levels. Most holders of the mutex > > > let it go very quickly. > > > > Ok but that surely should be implemented in the general mutex code then > > or at least in a standard adaptive mutex wrapper? > > That depends, am I the only one crazy enough to think its a good idea? Adaptive mutexes are classic, a lot of other OS have it. Gregory et.al. also saw big improvements in the RT kernel (they posted a patchkit a few times) But a lot of people don't like them for some reason. Anyways hiding them in a fs is probably wrong. -Andi -- ak@linux.intel.com