Date: Thu, 19 Jun 2003 01:27:13 -0700 From: David Schultz <das@FreeBSD.ORG> To: Mike Silbersack <silby@FreeBSD.ORG> Cc: cvs-all@FreeBSD.ORG Subject: Re: cvs commit: src/sys/kern kern_descrip.c Message-ID: <20030619082713.GC79448@HAL9000.homeunix.com> In-Reply-To: <200306181857.h5IIvwfY075070@repoman.freebsd.org> References: <200306181857.h5IIvwfY075070@repoman.freebsd.org>
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On Wed, Jun 18, 2003, Mike Silbersack wrote: > silby 2003/06/18 11:57:58 PDT > > FreeBSD src repository > > Modified files: > sys/kern kern_descrip.c > Log: > Reserve the last 5% of file descriptors for root use. This should allow > systems to fail more gracefully when a file descriptor exhaustion situation > occurs. > > Original patch by: David G. Andersen <dga@lcs.mit.edu> > PR: 45353 http://www.FreeBSD.org/cgi/query-pr.cgi?pr=45353 Please allow me to re-make the point I believe I made when the patch was submitted. (Of course, you're welcome to ignore it.) The reserve should be a tunable constant, not a fixed percentage. The idea, as I understand, is to allow the administrator to log in and correct the problem. On a server with 50000 struct files, the reserve doesn't need to be 2000; a reserve on the order of 100 open files should be adequate for just about any system. In other words, the reserve doesn't need to scale with the size of the system. I'm glad to see that you made the keen observation that it's important to check the real UID for rootness rather than the effective UID. And thanks for subsequently adding the rate-limited ``file table full'' diagnostics.
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