Date: Wed, 25 Mar 2015 12:06:46 +0100 From: Hans Petter Selasky <hps@selasky.org> To: Gleb Smirnoff <glebius@FreeBSD.org> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r280495 - head/sys/kern Message-ID: <551296C6.9070402@selasky.org> In-Reply-To: <20150325105409.GS64665@FreeBSD.org> References: <201503250855.t2P8tZFp038467@svn.freebsd.org> <20150325105409.GS64665@FreeBSD.org>
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On 03/25/15 11:54, Gleb Smirnoff wrote: > On Wed, Mar 25, 2015 at 08:55:35AM +0000, Hans Petter Selasky wrote: > H> Author: hselasky > H> Date: Wed Mar 25 08:55:34 2015 > H> New Revision: 280495 > H> URL: https://svnweb.freebsd.org/changeset/base/280495 > H> > H> Log: > H> Implement a simple OID number garbage collector. Given the increasing > H> number of dynamically created and destroyed SYSCTLs during runtime it > H> is very likely that the current new OID number limit of 0x7fffffff can > H> be reached. Especially if dynamic OID creation and destruction results > H> from automatic tests. Additional changes: > H> > H> - Optimize the typical use case by decrementing the next automatic OID > H> sequence number instead of incrementing it. This saves searching time > H> when inserting new OIDs into a fresh parent OID node. > H> > H> - Add simple check for duplicate non-automatic OID numbers. > > Why didn't you use alloc_unr(9) for that? > Hi Gleb, I thought about using alloc_unr(). The problem is that sysctls have no clear concept of freeing. For example in some existing code sysctl are unregistered and registered again assuming that the oid_number will be preserved. I didn't want touch those parts. Also, hence we are already traversing a list to insert an SYSCTL object in an ordered fashion, the benefit of alloc_unr() is not that big. What do you think? --HPS
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