Date: Sun, 1 Mar 1998 10:51:46 -0500 (EST) From: "John S. Dyson" <dyson@FreeBSD.ORG> To: dima@tejblum.dnttm.rssi.ru (Dmitrij Tejblum) Cc: tlambert@primenet.com, FreeBSD-current@FreeBSD.ORG Subject: Re: VM: Process hangs sleeping on vmpfw Message-ID: <199803011551.KAA02547@dyson.iquest.net> In-Reply-To: <199803011032.NAA02269@tejblum.dnttm.rssi.ru> from Dmitrij Tejblum at "Mar 1, 98 01:32:57 pm"
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Dmitrij Tejblum said: > > > > Unionfs. Specifically, the point is that the unionfs implementation > > should fan out to the correct underlying implementation. This means > > it shouldn't go into the default. > > But you must write correct getpages/putpages for unionfs in any case. > Or, better, make a bypass routine for unionfs, to avoid similar > problems with future new vnode operations :-). > Yes. FS types such as union and null where the files are exposed from multiple vantage points have severe coherency problems, and I will likely help take a look at those issues when this stuff all settles out. > > > Secondly, you can't make FS-specific optimizations. > > Nothing prevent a filesystem to implement its own getpages/putpages and > override the default. > Yes. The original scheme that we had implemented that, in a VM centric way (which was an expedient choice for me at the time.) The scheme was changed to look more VFS centric, and cannot say that is bad at all. I think that moving to a VFS centric approach is less "eccentric." :-). -- John | Never try to teach a pig to sing, dyson@freebsd.org | it just makes you look stupid, jdyson@nc.com | and it irritates the pig. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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