Date: Wed, 8 Nov 2000 01:08:14 +0000 (GMT) From: Terry Lambert <tlambert@primenet.com> To: phk@critter.freebsd.dk (Poul-Henning Kamp) Cc: drosih@rpi.edu (Garance A Drosihn), dillon@earth.backplane.com (Matt Dillon), bde@zeta.org.au (Bruce Evans), mckusick@mckusick.com (Kirk McKusick), arch@FreeBSD.ORG Subject: Re: softdep panic due to blocked malloc (with traceback) Message-ID: <200011080108.SAA01195@usr08.primenet.com> In-Reply-To: <27538.973633262@critter> from "Poul-Henning Kamp" at Nov 07, 2000 10:41:02 PM
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> >>Could we please have an eventhandler chain which gets called when > >>we are short of KVM ? There are code which can free KVM with no > >>significant loss of anything but performance, if only we bother to > >>tell it to do so. > > > >Do you mean something like the SIGDANGER signal, which is available > >under aix? (I'm just wondering) > > That too might be a very good idea. It's a user space signal, which can be caught to prevent termination of "precious" processes. It is also (infrequently) used for self checkpoint/restart, so it's caught to shutdown, rather than terminate processes. I haven't seen an occurrance of one in nature (well, AIX) in at least 5 years. A kernel event handler chain is probably a good idea (see previous notes on NT and Windows). The way it's usually handled is by not giving anyone who pools resources any allocations, unless they register a "give back as much as you can" handlers. It's amusing to note that VFAT only ever gave back exactly one page (some pigs are more equal than others). Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message
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