Date: Fri, 2 May 1997 11:04:33 +0100 (BST) From: Doug Rabson <dfr@nlsystems.com> To: Poul-Henning Kamp <phk@dk.tfs.com> Cc: current@freebsd.org Subject: Re: vnode->v_usage Message-ID: <Pine.BSF.3.95q.970502105721.331D-100000@herring.nlsystems.com> In-Reply-To: <207.862417862@critter>
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On Wed, 30 Apr 1997, Poul-Henning Kamp wrote: > In message <Pine.BSF.3.95q.970427143216.346G-100000@herring.nlsystems.com>, Dou > g Rabson writes: > >On Sun, 27 Apr 1997, Poul-Henning Kamp wrote: > >> > >> Unless somebody convinces me of the utility of this field, I will remove > >> it from the vnodes. > >> > >I think it is intended to be used to keep frequently used vnodes from > >being recycled by getnewvnode. > > Well, I've done it. Here is a patch that implements LRU for name-cache > hits on the vnode freelist. I doubt that it has any performance impact, > but it makes the vnode 4 bytes smaller, which is a good thing. > > Please test and report. I don't have any performance numbers but it seems to work fine. I think the cache should just call vtouch for all vnodes and not check the usage count. Also vtouch should take the v_interlock simple_lock before reading the v_usecount field as specified by vnode.h. I know we have a long way to go before we get to an SMP vfs but the Lite2 is a lot cleaner than the old code and we should try to keep to the rules when accessing fields of the vnode. -- Doug Rabson Mail: dfr@nlsystems.com Nonlinear Systems Ltd. Phone: +44 181 951 1891
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