Date: Sun, 24 Oct 2010 23:46:38 -0500 (CDT) From: Robert Bonomi <bonomi@mail.r-bonomi.com> To: freebsd-questions@freebsd.org, temporal@gmail.com Subject: Re: EVFILT_VNODE doesn't scale to large directory trees? Message-ID: <201010250446.o9P4kcid004004@mail.r-bonomi.com>
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> From owner-freebsd-questions@freebsd.org Sun Oct 24 22:17:42 2010 > Date: Sun, 24 Oct 2010 18:05:34 -0700 > From: Kenton Varda <temporal@gmail.com> > To: freebsd-questions@freebsd.org > Subject: EVFILT_VNODE doesn't scale to large directory trees? > > Hi all, > > I am trying to write some code which monitors a possibly-large directory > tree for changes. Specifically, it's a build system, and I want it to > automatically start rebuilding whenever I modify a source file. > > So far the approach I've taken is to use EVFILT_VNODE to watch every file > and directory in the tree. This seems to work OK so far, but it worries me > that I have to open() every single file. When I ran the same code on > Darwin, it promptly hit the open file descriptor limit, and I'm worried that > FreeBSD will do the same on larger code trees. > > Is there any better way to accomplish this? Hate to say it, but Linux's > inotify() seems more scalable here. From what I can tell from the docs, it > doesn't require opening the watched files and it will even watch all files > in a directory with one call. You're re-inventing the wheel. 1) Set up a 'makefile' for the entire tree. 2) set up a daemon task that a) cd's to the root direcory of the build tree, b) executes a loop, consisting of 1) the 'make all' command, 2) a reasonably short 'sleep' If 'efficiency' is a concern, then establish a procedure for checking-out/ checking-in files from the repository. When a file is checked in, check for (a) it being a new file, *OR* (b) having changes from the prior version. If either condition is true, fire off 'make' to do the necessary re-build. NOTE: 'cvs' has the above feature as a built-in option. simply specify 'make' as a program to be run when you do a 'cvs commit' to store changes back into the repository. Did I say soemthing about re-inventing the wheel?? <grin>
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